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Annual Report 2006 Jahresforschungsbericht 2006 Berichte des IGB Heft 24/2007 Leibniz-Institut für Gewässerökologie und Binnenfischerei Leibniz-Institute of Freshwater Ecology and Inland Fisheries im Forschungsverbund Berlin e.V. Annual Report 2006 Jahresforschungsbericht 2006 Herausgeber Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB) im Forschungsverbund Berlin e. V. Müggelseedamm 310, 12587 Berlin Direktor (kommissarisch) Prof. Dr. Gunnar Nützmann Gestaltung Antje Herrmann, Götz Greiner (Weimar) Druck ebert-druck + werbung Berlin ISSN Nr. 1432-508X © 2007 IGB Content Inhalt Preface Vorwort 1 The IGB – Structure and Services 12 Das IGB – Struktur und Service 1.1 Structure 12 Struktur 1.2 Administration 14 Institutsleitung 1.3 Scientific Advisory Board 15 Wissenschaftlicher Beirat 1.4 Staff 18 Mitarbeiter 1.5 Works Committee, Ombudsman and Equal Opportunity Commissioner 21 Betriebsrat, Ombudsmann und Gleichstellungsbeauftragte 1.6 Research Services 22 Service 2 Research Program 2005-2007 27 FE-Programm 2005-2007 3 Research Reports – Selected papers 31 Forschungsberichte – Ausgewählte Publikationen 3.1 Research Topic 1 Forschungsschwerpunkt 1 31 Environmental signalling Umweltbedingte chemische Kommunikation 3.1.1 Environmental pollution by bisphenol A: sources and fate in the Elbe basins and biological effects Umweltverschmutzung durch Bisphenol A: Einträge und Stoffverhalten im Elbe-Einzugsgebiet sowie biologische Wirkungen JAGNYTSCH , O., KRÜGER , A., O PITZ , R., LUTZ , I., B EHRENDT, H., KLOAS , W. 33 3.2 Research Topic 2 Forschungsschwerpunkt 2 43 Processes at interfaces Prozesse an Grenzflächen 3.2.1 Reconstruction of pristine morphology, flow, nutrient 45 conditions and submerged vegetation of lowland River Spree (Germany) from palaeomeanders Rekonstruktion der Referenzbedingungen der Unteren Spree hinsichtlich Morphologie, Abfluss, Nährstoffkonzentrationen und Unterwasservegetation aus Paläomäandern HILT, S., S CHÖNFELDER , I., RUDNICKA, A., CARLS , R., N IKOLAEVICH, N., S UKHODOLOV, A., E NGELHARDT , C. 3.2.2 Infiltration of surface water into ground-water 55 under transient pressure gradients Infiltration von Oberflächenwasser in den Grundwasserleiter bei instationären Druckgradienten W IESE , B., N ÜTZMANN ,G.. 3.2.3 Modelling dissolved oxygen dynamics in ice-covered 65 shallow lakes Modellierung des dynamischen Sauerstoffverbrauchs in zugefrorenen Flachseen G OLOSOV, S., K IRILLIN, G.. 3.3 Research Topic 3 Forschungsschwerpunkt 3 75 Adaptation, plasticity, and dynamics of communities Adaptation, Plastizität und Dynamik von Biozönosen 3.3.1 Detection and phylogenetic characterization of 77 polyphosphate accumulating bacteria in lake sediments Nachweis und phylogenetische Charakterisierung von Polyphosphat-akkumulierenden Bakterien in Seesedimenten G LOESS , S., HUPFER , M., R ATERING, S., G ROSSART, H.-P.. 3.3.2 Depth distribution of abundant benthic invertebrates in Lake Stechlin Tiefenverteilung von häufigen benthischen Wirbellosen im Stechlinsee HELLAND, I.P., B RAUNS , M., F REYHOF ,J. 89 3.4 Research Topic 4 Forschungsschwerpunkt 4 97 Sustainable management of aquatic ecosystems Nachhaltiges Gewässermanagement 3.4.1 Do littoral habitats with high structural complexity mitigate 99 the impact of ship-induced waves on benthic invertebrates? Reduzieren literorale Habitate mit hoher struktureller Komplexität die Auswirkungen schiffsinduzierten Wellenschlags auf benthische Wirbellose? G ARCIA , X.-F., G ABEL , F., H OCHMUTH , H., B RAUNS , M., S UKHODOLOV, A., P USCH , M.. 3.4.2 Integrated protection of surface waters 109 Integrierter Gewässerschutz von Binnengewässern K OSCHEL , R., B EHRENDT, H., HUPFER , M.. 3.4.3 Dissolved organic matter (DOM) modulates the cadmium 121 accumulation in zebrafish (Danio rerio) embryos Huminstoffe beeinflussen die Cadmium-Akkumulation in Zebrabärblingsembryonen (Danio rerio) M EINELT, T., B URNISON, B. K., P LAYLE , R., P IETROCK , M., W IENKE , A., S TEINBERG , C.E.W. 3.4.4 Towards improved management of infection in 131 aquaculture: strategies arising from the host-parasite interactions in rainbow trout Oncorhynchus mykiss and the pathogenic flagellate Spironucleus salmonis Wege zu einem verbesserten Management von Infektionskrankheiten in der Aquakultur: Strategien basierend auf der Wirt-Parasit Interaktion zwischen der Regenbogenforelle Oncorhynchus mykiss und dem pathogenen Flagellaten Spironucleus salmonis P OYNTON, S.L., S AGHARI F ARD, M.R., B LEISS , W., J ØRGENSEN , A., W EISHEIT, C., M EINELT , T., RENNERT, B., C HENG , J., K IRSCHBAUM , F., KNOPF , K. 3.4.5 Growth performance and body composition of carp (Cyprinus carpio) fed diets containing housefly maggot meal (magmeal) Wachstum und Körperzusammensetzung von Karpfen (Cyprinus carpio) denen Futtermittel mit Fliegenmadenmehl verabreicht wurden O GUNJI , J.O., S UTTER , D., RENNERT, B., KLOAS , W., S CHULZ , C. 140 4 Statistics Statistik 149 4.1 Peer-reviewed papers 151 Artikel in referierten Zeitschriften 4.2 Non-reviewed papers, books, book chapters and reports 161 Artikel in nichtreferierten Zeitschriften, Bücher, Buchbeiträge und Berichte 4.3 Degrees 168 Abschlüsse 4.3.1 Bachelor and Master Theses 168 Bachelor- und Diplomarbeiten 4.3.2 PhD Theses 169 Doktorarbeiten 4.3.3 Pre-Professional Theses 170 Habilitationen 4.4 Lectures at universities 171 Vorlesungen an Universitäten 4.5 Memberships in Scientific and Editorial Boards 174 Verantwortliche Positionen in Fachgesellschaften oder Gremien 4.6 Projects and Grants 176 Projekte und Stipendien 4.7 Summary 184 Gesamtübersicht 4.8 List of published IGB reports Liste der bisher veröffentlichten Berichte des IGB 185 Preface Vorwort Freshwater is the earth’s most valuable natural resource. The main challenge of our century is to reconcile the needs for water in human societies with the requirements for healthy freshwater ecosystems. Management of these resources must rely upon the best available scientific knowledge including the factors controlling the structure, function, quality, and quantity of freshwaters. Based on these premises the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB, established on 1 January 1992) is engaged in studies comprizing the functioning, diversity, and management of freshwater ecosystems based on multidisciplinary research activities. Research areas typically located in NE Germany and adjoining regions include: interactions between surface and groundwater, deep stratified and shallow lakes, shallow lakes interconnected with lowland rivers, river stretches and ponds. The state Brandenburg e.g., is characterized by more than 3.000 lakes of various sizes and characteristics indicating the need for substantial research. The IGB’s national and international reputation in the field of aquatic ecology has grown steadily and the Institute - comprising approximately 150 staff members and about 50 PhD-students - houses now many prestigious hydrological, limnological, and fish ecological research groups. During the year 2006 the completion of the new aquarium hall – the inauguration ceremony took place on the 4th of October – marked a further step towards the development of a modern research Institute. The facilities comprise several independent re-circulatory systems and facilities for various experimental research activities; these potentials which will further tighten the cooperation with institutions at the national and international level. At the end of 2006 the candidates for the open post of the director of the Institute have presented their ideas on the scientific development of the IGB. The final decision concerning the open post will be taken in 2007 and this new personal situation will certainly also have impact on the future research program of the IGB. The scientific activities of our Institute are summarized in annual research reports. We have selected 11 topics from our research programme comprising four key areas: 1) environmental signalling, 2) processes at aquatic interfaces, 3) adaptation, plasticity, and dynamics of aquatic communities and 4) sustainable management of aquatic ecosystems. From 1997 to 2005 the annual reports were prepared by the departments of the IGB. The report for 2006 for the first time has been managed in part by the department IV (Dr. Wolter), and by the head of the library, Mrs. Grosse. We would like to thank them for their effort and all colleagues for the work accomplished in 2006. © IGB 2007 Frank Kirschbaum Gunnar Nützmann Department of Biology and Ecology of Fishes Director (in charge) 9 Improved experimental facilities – the new aquaria hall After two years of construction work IGB’s new aquaria hall was solemnly inaugurated on October 04, 2006. The architecturally strict and functional building is situated at Müggelseedamm 310. On two floors it has a main usable space of more than 1000 m², climate chambers, labs, a dissection lab and a modern seminar room for lectures and conferences. The largest basins have a volume of 36000 l each, and therein swim among others mature sturgeons. Other aquaria and circulation systems contain pike perch, carp, roach, eel, zebra fish and striped mullets used in several distinct experiments and projects. The total costs of 2.46 billion Euros have been financed to equal parts (985,000 € each) by the Berlinean Senate and the Federal Ministry of Education and Research as well as by the European Union (EFRE 460,000 €). On the other hand, the new improved experimental facilities enabled the raising of 10 projects with a total budget of 2.43 billion Euros and 17.5 temporary positions since 2005. 10 The main aquaria hall in the basement has nine separate, closed circulation systems used for harvesting the sturgeon breeding stock, as well as for various experiments with eels (previous page), carp, tilapia and other fish species. Photos IGB/Ralf Günter Each circulation system has its own prufication unit, with mechanical and biological treatment. In addition ozonisation and UV-desinfection are possible. © IGB 2007 11 12 Administration Director Rivers Prof. Dr. N. Walz Prof. Dr. R. Koschel Shallow Lakes Prof. Dr. G. Nützmann Stratified Lakes Limnology of and Lowland Limnology of Department II Department I Ecohydrology Prof. Dr. F. Kirschbaum Fishes Ecology of Biology and Department IV Prof. Dr. W. Kloas Inland Fisheries Department V Dr. J. Gelbrecht Laboratory Chemical Central G. Krätsch M. Sieber J. Hochschild Department III Administration Team Technical Team Dr. F. Fabich Library Prof. Dr. G. Nützmann Director (in charge) Information Technology Team Prof. Dr. H. E. Segner (chair) Scientific Advisory Committee Board of Directors of the Research Association Berlin e. V. Structure Board of Trustees General Meeting 1.1 Member of the Research Association Berlin e.V. Leibniz-Institute of Freshwater Ecology and Inland Fisheries 1 The IGB – Structure and Services Das IGB – Struktur und Service Struktur Further Information Weitere Informationen Supporting Organisations Federal Government (BMBF) and Country of Berlin each 50% Organisation The institute is a member of the Research Association Berlin e.V. (see structure of IGB) Staff (from 31.12.2006) 39 24 11 26 68 5 Scientists (internally funded) Scientists (project or grant funded) Ph.D. students (internally funded) Ph.D. students (project or grant funded) Technical and administrative staff (internally funded) Technical staff (project or grant funded) Annual budget 8,500,000 € Publications The scientific results are continuously published in national and international journals. Lists of all publications in which staff members are involved are published regularly in the “Berichte des IGB” / Annual Reports Journals „International Review of Hydrobiology” (ISSN 1434-2944) „Limnologica” (ISSN 0075-9511) „Berichte des IGB“ (ISSN 1432-508X) © IGB 2007 13 1.2 Administration Institutsleitung Director (in charge) Prof. Dr. Gunnar Nützmann Müggelseedamm 310 12587 Berlin phone: +49 (0) 30 - 64 181 661 fax: +49 (0) 30 - 64 181 663 e-mail: [email protected] 14 Head of Administration G. Krätsch Müggelseedamm 310 12587 Berlin phone: +49 (0) 30 - 64 181 603 fax: +49 (0) 30 - 64 181 600 e-mail: [email protected] Secretary B. Spieler Müggelseedamm 310 12587 Berlin phone: +49 (0) 30 - 64 181 602 fax: +49 (0) 30 - 64 181 600 e-mail: [email protected] Head of Department I Ecohydrology Prof. Dr. G. Nützmann Müggelseedamm 310 12587 Berlin phone: +49 (0) 30 - 64 181 661 fax: +49 (0) 30 - 64 181 663 e-mail: [email protected] Head of Department II Limnology of Shallow Lakes and Lowland Rivers Prof. Dr. N. Walz Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 - 64 181 680 fax: +49 (0) 30 - 64 181 682 e-mail: [email protected] Head of Department III Limnology of Stratified Lakes Prof. Dr. R. Koschel Alte Fischerhütte 2 16775 Stechlin-Neuglobsow phone: +49 (0) 330 82 - 69 90 fax: +49 (0) 330 82 - 69 917 e-mail: [email protected] Head of Department IV Biology and Ecology of Fishes Prof. Dr. F. Kirschbaum Müggelseedamm 310 12587 Berlin phone: +49 (0) 30 - 64 181 610 fax: +49 (0) 30 - 64 181 750 e-mail: [email protected] Head of Department V Inland Fisheries Prof. Dr. W. Kloas Müggelseedamm 310 12587 Berlin phone: +49 (0) 30 - 64 181 630 fax: +49 (0) 30 - 64 181 799 e-mail: [email protected] Head of Central Chemical Laboratory Dr. J. Gelbrecht Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 - 64 181 730 fax: +49 (0) 30 - 64 181 682 e-mail: [email protected] 1.3 Scientific Advisory Committee Wissenschaftlicher Beirat Prof. Dr. H. E. Segner address: phone: fax: e-mail: member since: Prof. Dr. H. Rosenthal address: phone: fax: e-mail: member since: Prof. Dr. E. van Donk address: phone: fax: e-mail: member since: Prof. Dr. W. Endlicher address: phone: fax: e-mail: member since: © IGB 2007 Chair of Advisory Committee Zentrum für Fisch- und Wildtiermedizin am Institut für Tierpathologie Universität Bern Länggass Straße 122 CH-3012 Bern +41 (0) 31 – 63 12 441 +41 (0) 31 – 63 12 611 [email protected] 01.01.2002 Deputy Chair of Advisory Committee Schöfferstraße 48 21629 Neu Wulmsdorf +49 (0) 40 – 70 06 514 +49 (0) 40 – 67 01 02 676 [email protected] 01.12.2000 Department of Food Web Studies Institute of Ecology Rijksstraatweg 6 3631 Nieuwersluis The Netherlands +31 (0) 294 – 239 353 +31 (0) 294 – 232 224 [email protected] 01.12.2004 Humboldt-Universität zu Berlin, Mathem.-Naturwissensch. Fakultät II Geographisches Institut Unter den Linden 6 Sitz: Rudower Chaussee 16 10099 Berlin +49 (0) 30 – 20 93 68 08 +49 (0) 30 – 20 93 68 44 [email protected] 01.01.2003 15 Dr. K. Fent address: phone: fax: e-mail: member: Prof. Dr. F. Frimmel address: phone: fax: e-mail: member since: Prof. Dr. U. Grünewald address: phone: fax: e-mail: member since: Prof. Dr. E. A. Huisman address: phone: e-mail: member: 16 Institut für Umwelttechnik Fachhochschule beider Basel St. Jakobs-Strasse 84 CH-4132 Muttenz +41-(0)61-467 45 05 +41-(0)61-467 42 90 [email protected] [email protected] 01.12.1998 - 30.11.2006 Universität Karlsruhe (TH), Engler-Bunte-Institut, Lehrstuhl für Wasserchemie Richard-Willstätter-Allee 5 76131 Karlsruhe +49 (0) 721 – 60 82 581 +49 (0) 721 – 69 91 54 [email protected] 01.12.2000 Brandenburgische Technische Universität Cottbus, Fakultät Umweltwissenschaften und Verfahrenstechnik Postfach 10 13 44 03013 Cottbus +49 (0) 355 69 42 33 +49 (0) 355 69 42 35 [email protected] 01.12.2004 Institute of Animal Sciences Wageningen c/o Koningsweg 6 NL-66 55 AC Puiflijk +31 (0) 487 – 51 56 79 [email protected] 01.12.2000 - 06.10.2006 Prof. Dr. W. Lampert address: phone: fax: e-mail: member: Prof. Dr. S. Peiffer address: phone: fax: e-mail: member since: Prof. Dr. K.-J. Peters address: phone: fax: e-mail: member since: Prof. Dr. Th. Weisse address: phone: fax: e-mail: member since: © IGB 2007 Max-Planck-Institut für Limnologie Plön Postfach 165 24302 Plön +49 (0) 45 22 – 76 32 70 +49 (0) 45 22 – 76 33 10 [email protected] 01.12.1998 - 30.11.2006 Universität Bayreuth Lehrstuhl für Hydrologie 95440 Bayreuth +49 (0) 921 55 22 51 +49 (0) 921 55 23 66 [email protected] 01.12.2004 Humboldt-Universität zu Berlin Institut für Nutztierwissenschaften Phillippstr. 13 10115 Berlin +49 (0) 30 – 20 93 63 63 oder -62 +49 (0) 30 – 20 93 63 70 [email protected] 01.01.2003 Institut für Limnologie Österreichische Akademie der Wissenschaften Mondseestr. 9 A-5310 Mondsee +43 (0) 6232 - 3125 +43 (0) 6232 - 3578 [email protected] 01.12.2004 17 1.4 Staff (December 31, 2006) Mitarbeiter (31. Dezember 2006) Director Internally funded Nützmann, Gunnar Sakowsky, Alexandra Spieler, Brigitte Administration and Technical Team Internally funded Albrecht, Gerda Bednarz, Stefan Gaertner, Hartmut Gürtler, Frido Krätsch, Gisela Schäricke, Kerstin Schmidt, Mathias Information Technology Team Internally funded Henke, Vera Hochschild, Johannes Kalberg, Christian Voß, Astrid Library Internally funded Große, Christine (since 09/2006) Hentschel, Ute Sieber, Magdalena (till 07/2006) Central Chemical Laboratory 18 Internally funded Project or grant funded Exner, Hans-Jürgen Gelbrecht, Jörg Guder, Sylvia Herzog, Christiane Hupfer, Michael Krüger, Angela Lüder, Antje Rossoll, Thomas Schütze, Bernd Zwirnmann, Elke Kleeberg, Andreas Żak, Dominik Ecohydrology (Dept. I) Internally funded Project or grant funded Brüggemann, Rainer Bungartz, Heinz Engelhardt, Christof Friedrich, Hans-Jörg Kobisch, Barbara Lewandowski, Jörg Nützmann, Gunnar Schwamm, Dagmar Siegert, Grit Sukhodolov, Alexander Ginzel, Gerhard Golosov, Sergey Hamann, Enrico Horner, Christoph Kirillin, Georgiy Molkenthin, Christian Schnauder, Ingo Suhodolova, Tatiana Limnology of Shallow Lakes and Lowland Rivers (Dept. II) Internally funded Project or grant funded Adrian, Rita Behrendt, Horst Graupe, Marianne Hintze, Thomas Hölzel, Reinhard Klockau-Raddatz, Sylvia Köhler, Jan Kozerski, Hans-Peter Lehmann, Katrin Meinck, Barbara Newen, Ursula Pusch, Martin Täuscher, Helgard Walz, Norbert Winkler, Hanna Bauer, Nadine Brauns, Mario Carl, Peter Gericke, Andreas Hilt, Sabine Hirt, Ulrike Hofmann, Jürgen Huber, Veronika Leszinski, Marc Mischke, Ute Opitz, Dieter Strube, Torsten Venohr, Markus Wagner, Carola Wilhelm, Susann (till 10/2006) Limnology of Stratified Lakes (Dept. III) © IGB 2007 Internally funded Project or grant funded Allgaier, Martin Beyer, Ute Casper, Peter Dalchow, Johanna Degebrodt, Monika Degebrodt, Roman Glöß, Stefanie Grossart, Hans-Peter Kasprzak, Carola Kasprzak, Peter Koschel, Rainer Krienitz, Lothar Mach, Elke Mallok, Uta Papke, Monika Pommerening, Eleonore Roßberg, Reingard Sachtleben, Michael Scheffler, Adelheid Schulz, Marina Tesch, Edith Wiedner, Claudia Dziallas, Claudia Eixler, Sebastian Hutalle, Kristine Michelle L. Jander, Jörn Koppe, Cathleen Rychla, Anna Sergelen, Gongor Stüken, Anke Wauer, Gerlinde 19 Biology and Ecology of Fishes (Dept. IV) Internally funded Project or grant funded Arlinghaus, Robert Daedlow, Katrin Faller, Markus Fischer, Leonore Freyhof, Jörg Helms, Christian Kirschbaum, Frank Kuntze, Karena Löschau, Peter Mehner, Thomas Ohlberger, Jan Osman, Alaa Gad El-Karim Mahmoud Pohlmann, Kirsten Rohde, Titus Simon, Marcel Staaks, Georg Stelbrink, Björn Türck, Alexander Uusi-Heikkilä, Silva Wolter, Christian Zwadlo, Henrik Baganz, Daniela Beardmore, Alan Benedict Dorow, Malte Garcia, Xavier-Francois Geßner, Jörn Helland, Palm Ingeborg Huckstorf, Volker Lewin, Wolf-Christian Würtz, Sven-Holger Inland Fisheries (Dept. V) 20 Internally funded Project or grant funded Ballegooy, Christoph van Cuppok, Ingo Hübner, Bettina Kersten, Petra Kloas, Werner Knopf, Klaus Kohlmann, Klaus Kunow, Mathias Lorenz, Claudia Lutz, Ilka Meinelt, Thomas Neumann, Nadja Nimptsch, Jorge Pflugmacher, Stephan Pietsch, Constanze Rennert, Bernhard Schumacher, Wibke Stüber, Angelika Tillack, Antje Urbatzka, Ralph Vassilakaki, Maria Viehmann, Viola Wiedemann, Caterina Wiegand, Claudia Ballot, Andreas Contardo Jara, Valeska Fard, Mohammad Reza Saghari Frank, Sabrina Grigutyte, Reda Jagnytsch, Oana Kamara, Sheku Menzel, Ralph Opitz, Robert Peuthert, Anja Rienau, Stefanie Trubiroha, Achim 1.5 Works Committee, Ombudsman and Equal Opportunity Commissioner Betriebsrat, Ombudsmann und Gleichstellungsbeauftragte Chairman E. Zwirnmann Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 – 64 181 735 e-mail: [email protected] P. Casper Alte Fischerhütte 2 16775 Stechlin-Neuglobsow phone: +49 (0) 33 082 – 69 929 e-mail: [email protected] C. Engelhardt Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 – 64 181 664 e-mail: [email protected] M. Kunow Müggelseedamm 310 12587 Berlin phone: +49 (0) 30 – 64 181 702 e-mail: [email protected] Th. Hintze Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 – 64 181 689 e-mail: [email protected] J. Dalchow Alte Fischerhütte 2 16775 Neuglobsow phone: +49 (0) 33 082 – 69 916 e-mail: [email protected] K. Wagner Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 – 64 181 693 e-mail: [email protected] Ombudsman “Safeguarding good scientific practice” M. Hupfer Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 – 64 181 605 e-mail: [email protected] Equal Opportunity Commissioner A. Krüger Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 – 64 181 735 e-mail: [email protected] © IGB 2007 21 H OCHSCHILD , J. 1.6 Research Services Service 1.6.1 Information Technology Team Informatik und Rechentechnik The Information Technology Team (ITT) of the IGB provides computer, software and net equipment for all research departments, management offices, and the library in our institute. That means to design, to set up and to maintain the intra-network, file and application services and, last but not least, the connection to the internet (e-mail, www, ftp, vpn, etc). The largest part of ITT’s task spectrum is the maintenance of the workplace computer pool (Intel PCs, mostly running MS-Windows, W2K), which consists of approximately 500 PCs, including 100 computers for special jobs in the laboratories and 80 notebooks. In addition to the hardware and operating system oriented activities, ITT has also to purchase, install, set up and evaluate standard and special software. In a lot of cases ITT is even developing new software solutions, e.g. a measurement database, interface software for measuring devices, and a cgi access to the IGB literature catalogue for the IGB website. The next, just as important, part of ITT’s area of responsibility is the administration and maintenance of the big fileservers and the pool of special servers. A very important field to do it is the safeguarding of the data stored on the servers, against any loss or destruction. For this purpose ITT developed a novel system with a special magnetic tape library, so that data can be restored up to three month backdated. For higher security and good availability of IGB’s data pool, in 2004 began the use of Server-RAIDsystems. In the following years the use of RAID-systems was powerful expanded. Beginning in the October 2006 in the IGB was installed a Wireless Local Area Network. The scientists and students have now easy accesses to the internet and the common IGB network with their notebooks on any places in the IGB buildings. For the other services, such as email, databases, etc. the server pool still containing several HP, IBM RS6000, SUN, Compaq Alpha, and Intel/Linux servers. Some SUN and Intel workstations perform special jobs for simulations and special numerical calculations. ITT also maintains some web servers e.g. "www.igb-berlin.de" or “www.adaptfish.igb-berlin.de” or “www.flake.igb-berlin.de” and supports the activities of the research departments in developing their own homepages, and guarantees the web presentation of the IGB, which is of great importance for the publicity of the institute. With the ever growing expansion of the internet, we are permanently faced with different security problems in the IGB network. By setting up and maintaining a firewall router, we spend a great deal of our resources on the protection of the systems from actions of foreign hackers. 22 The IGB has its own internet domain, named "igb-berlin.de". All scientists, staff and guest researchers and the technical staff can use the internet and e-mail services, web browsers and FTP-tools directly from their workplaces. Incoming and outgoing e-mails are collected in a common mail host, where viruses and spam mails are filtered out, so that only checked mails are distributed to the recipients. Infected mails are returned to the senders. In order to print documents and graphics, members of the institute have access to more than 80 greyscale and colour laser printers. Posters can be designed and printed with equipment consisting of a graphic workstation and a DIN-A0-HP-Posterjet 5000. Other periphal devices include scanners, slide exposers, digitalising tablets, projectors and notebooks. The IGB administration is working with a SAP/R3 database. Seven PCs are connected by X21/ISDN wires with a central SAP system. The most used software applications in the IGB are MS-Office, CorelDraw 12, Havard-Graphics 4.0, SigmaPlot, Origin, Mathlab, ModelMaker, SPSS, SAS, AVS, Esri’s GIS “ArcInfo/ArcView”, Reference Manager, BISLOK and the programming languages C/C++, Java, Fortran, Simula and Pascal. In 2006 for the first time was provided a “Windows 2003 Server” configured as a terminal server to make available comprehensive statistical and other special software to the workplace pcs. The freeware SAMBA, running on the UNIX-machines, is used to resolve the network file services. © IGB 2007 23 G ROSSE , C H . 1.6.2 Library Bibliothek General information The library is a special scientific library providing the central information supply for the Leibniz-Institute of Freshwater Ecology and Inland Fisheries. The information transfer is determined by the research profile of the institute, and subject specialisations in limnology, ecohydrology, geohydrodynamics, fishery sciences and water management. While the library mainly serves to support the employees of the IGB with literature, visitors and students can also use the library, under slightly restricted conditions. Tasks and services acquisitions (literature selection and literature procurement by - purchase, exchanges and gifts) bibliographical search through international and external data bases documentation of IGB publications literature supply from other facilities via inter-library loan publications: list of periodicals, new acquisitions list supply of books Library software BIS-LOK Version 5, Alephino 3.0 (change 09/2006) Search possibilities In the library: alphabetical and classified catalogues (accessioning of the bookstock before 2002) OPAC =Online Public Access Catalogue (proof of all bookstock) ASFA = Aquatic Science and Fisheries Abstracts (for 1978 to 2002, CD-ROM) Online: ISI/JCR = Institute for Scientific Information/Journal Citation Reports ISI/WoS = Institute for Scientific Information/Web of Sciences Use - 24 open access library reference collection – loan to employees Technical provision 18 reading seats - 3 PC work stations with internet access 2 microfilm readers photocopier Users employees of the institute, guests researchers, students and other - external users Opening hours for employees and guests during normal working hours at the - institute external users according to agreement by telephone Staff Magdalena Sieber (till 08/2006) Christine Große (since 09/2006) Head of Library phone: 030/64 181 655 fax: 030/64 181 676 e-mail: [email protected] [email protected] © IGB 2007 Ute Hentschel Librarian phone: 030/64 181 656 fax: 030/64 181 676 e-mail: [email protected] 25 P OYNTON , S. L. 1.6.3 Scientific Communications Skills: Advanced Course Wissenschaftliche Kommunikation: Kurse für Fortgeschrittene The commitment of IGB to supporting the professional development of its members was shown again in summer 2006, when scientists in Berlin had the opportunity to participate in a course entitled “Scientific Communication Skills: Advanced Level”. The intensive course, taught in English, focussed on the strategies and skills needed to make the transition from good to excellent scientific communications. The course began with a brief review of the history of scientific communication, and recognised that over the millennia, many different languages have been dominant, including Latin, Greek, Chinese, German, French, and currently English. Special consideration was then given to some stylistic differences in writing styles between German and English, and avoidance of common errors in usage. When examining the art of scientific writing, participants learned how to craft effective – audience specific –titles, how to write persuasive introductions and discussions, the importance of strong opening and closing sentences and paragraphs, and how to write smoothly flowing elegant texts. By comprehensive class critique of published texts, and those currently being written by the participants, the class learned to recognise strong and weak writing styles, and began to develop skills for editing texts for content, form and style. In addressing spoken communication skills, emphasis was placed not only on the content of a presentation, but also on the crucial importance of effective delivery. Participants had many opportunities to practice giving presentations on different topics, and in a variety of formats. In each class, feedback was given on correct vocabulary, grammar and pronunciation. For this advanced course, attention was also drawn to broad aspects of professional development, such as networking, leadership, and active and effective participation in conferences. The participants brought to the course, a diversity of research expertise, levels of experience, and language skills, which greatly enriched the learning environment. The small class size ensured intense interaction, individual attention, and many opportunities to speak English. The course was taught by Dr. Sarah Poynton, an experienced research scientist and international educator, who has directed and taught the Scientific Communications Skills program in IGB for nearly 10 years. Classes were competently supported by Dr. Poynton’s teaching assistant, Mr. M. Reza Saghari Fard, a Ph.D. student from Department V. 26 2 Research Program 2005-2007 FE-Programm 2005-2007 2.1 Focus 1: Environmental signalling Focust 1: Umweltbedingte chemische Kommunikation Co-ordinator: Werner Kloas The highly evolved sensitivity of signal receptors to exogenous chemical stimuli can make organisms vulnerable to natural compounds and man-made chemicals that mimic specific chemical cues or interfere with receptors. The environmental signalling research programme will focus upon the stimuli emitted by cyanobacterial secondary metabolites, natural biogeochemicals and endocrine disrupters, and will determine their effects on molecular modes of action, organisms and ecosystems. We investigate various aspects of signalling, biotransformation processes, signal pathways via reactive oxygen species (ROS), receptor signal transduction and gene expression, in a range of aquatic organisms from cyanobacteria to vertebrates, thus encompassing multiple compartments of lake ecosystems. The studies emphasize broadening and deepening our understanding of how aquatic organisms perceive and respond to both internal and external signals in order to ensure appropriate changes in their cellular metabolism, energy allocation, growth, development, reproduction and behaviour. Since many effects of environmental signalling are phenomenological, the major research effort will elucidate the corresponding modes of action. The central focus of our research will seek to determine if environmental signalling by natural compounds (cyanobacterial secondary metabolites and humic substances), as well as by natural and man-made endocrine disrupters, have the potential to significantly impact individual organisms and, in turn, also populations. Thus these mechanistic approaches to research will create information for potential risk assessment of aquatic ecosystems. 2.2 Focus 2: Processes at interfaces Focus 2: Prozesse an Grenzflächen Co-ordinators: Gunnar Nützmann, Norbert Walz In the glacially formed landscape of North-Eastern Germany, nutrients and energy are mutually transformed and transported at the interfaces between groundwater and sediment and between sediment and surface water. This situation raises the question as to how the amount and the velocities of these transformations underlie biological, chemical or physical processes. We will focus on quantifying the exchange processes at these interfaces in order to better understand the underlying mechanisms and to provide a foundation for better modelling. © IGB 2007 27 In this subject group, we focus on a unique combination of expertise in different disciplines (hydrology, mathematical modelling, water chemistry, macrophyte- plankton-and benthos-ecology) as wellas on the hydrology and biogeochemistry of this landscape. Project 2.1 (Hydrodynamic control of fluxes and biota) is desiqued to study the turbulent currents in rivers and lakes which influence all processes at the interfaces between open water and the biota. In projects 2.2, 2.3 and 2.4 processes occurring at specific interfaces are examined: the exchange of ground and surface water through the sediment (Project 2.2, Connectivity between ground and surface waters), the biogeochemical transformations between sediment and surface water, especially their promotion by biological factors (Project 2.3, Biogeochemical processes in microzones) and the biological exchange between benthic structures and open water that determine the ecological status of shallow waters (Project 2.4, Benthic pelagic coupling and bistability in shallow systems). 2.3 Focus 3: Adaptation, plasticity, and dynamics of communities Focus 3: Adaptation, Plastizität und Dyanmik von Biozönosen Co-ordinator: Rainer Koschel Research focus 3 will identify ecological and evolutionary based optimisation strategies of speciation and of biodiversity. A better understanding of adaptation, plasticity and dynamics of microorganisms, plankton and fish communities will lay a new theoretical foundation for the sustainable management of aquatic ecosystems. Our research builds upon previous IGB investigations of lowland ecosystems as the lakes Müggelsee, Stechlin and Breiter Luzin and the rivers Spree and Oder. Project 3.1 “Structuring of microbiota by biological interactions” will examine the genotype and chemotype diversity and phenotypic plasticity of bacteria, methanogenic archaea, cyanobacteria and algae. Project 3.2 “Regulation of fish diversity in running waters” is focused on key abiotic factors, life history differentiation and hybridisation of sturgeon species. Project 3.3 “Ecological factors in speciation of fishes” will address differential ecological adaptation and sympatric speciation of cisco species (Coregonus spp.). Project 3.4, directed to “Climate change biology”, is guided by the hypothesis that climate changes induce long-term changes in the phenology of plankton and subsequent pertubations in species interactions. 28 2.4 Focus 4: Sustainable management of aquatic ecosystems Focus 4: Nachhaltiges Gewässermanagement Coordinator: Christian Wolter Research focus 4 was established in 2000 to develop scientifically rigorous approaches for adaptive and sustainable water and ecosystem management strategies in freshwaters. The individual projects are primarily designed to facilitate sustainable use and to expand our knowledge of the structure and functioning of freshwater ecosystems. This approach supports the statutory mission of the IGB, which includes transfer of the results of basic ecologic research into applied science. Our results include the development of in-lake restoration techniques, assessment schemes for biological classifications of lakes and rivers, and a characterization of recreational fisheries as one of the major users of fish stocks. In future, integrative management options will be analysed and evaluated, such as reduction of external nutrient loading combined with in-lake ecological engineering, biodiversity protection and conservation-driven fisheries management, to maximize stakeholder benefits and minimize environmental impacts. The response of stagnant and running freshwater systems to restoration measures will be used as large-scale scientific experiments to improve the ecosystem theory of degraded water systems and to promote the costs-by-cause principle in conservation. In urban areas, the ecological potential of heavily modified water bodies will be assessed to aid in the implementation of the Water Framework Directive (WFD). Beyond 2008 we will attempt to integrate ecological and socio-economic studies to reflect the human dimensions in natural resource management. This work will be done in co-operation with social and economic research institutes and by expanding our own scientific expertise. Research focus 4 comprises the following projects: 4.1 Management of river systems: development of ecological knowledge to support sustainable restoration and management concepts for running waters. 4.2 Ecological engineering and lake ecosystem development: long-term analyses of manipulated and restored, deep, thermally-stratified lakes and drainage basins in Germany’s Baltic Lake District. 4.3 Inland Fisheries: development of sustainable aquaculture strategies to support the improvement of fish culture while minimising environmental impacts. Furthermor, we seek a holistic understanding of the human and biological component of fisheries systems and their management. © IGB 2007 29 30 3 Research Reports – Selected Papers Forschungsberichte – Ausgewählte Publikationen 3.1 Research Topic 1 Forschungsschwerpunkt 1 Environmental signalling Umweltbedingte chemische Kommunikation © IGB 2007 31 32 J AGNYTSCH , O., K RÜGER , A., O PITZ , R., L UTZ , I., B EHRENDT , H., K LOAS , W. 3.1.1 Environmental pollution by bisphenol A: sources and fate in the Elbe basins and biological effects Umweltverschmutzung durch Bisphenol A: Einträge und Stoffverhalten im Elbe-Einzugsgebiet sowie biologische Wirkungen Key words: bisphenol A, emission, retention, endocrine disruptor, Xenopus laevis, thyroid system, reproductive system Abstract Households and industrial discharges are the main sources of bisphenol A (BPA), an environmental chemical suspected to cause severe effects on endocrine systems, in surface waters. The emissions are realised by waste water treatment plants (WWTP) and combined sewer systems as well as industrial direct discharges. It was estimated that the total inputs into the river system of Elbe are about 970 kg/a by WWTP, 70 kg/a by sewer systems and 510 by two industrial discharges in the Czech part of Elbe. The retention within the surface waters of Elbe is 790 kg/a or 51%. Xenopus laevis premetamorphic tadpoles at stages 48 and 51 were exposed to different BPA concentrations ranging from 223 ng/L to 223 µg/L to analyse effects on sexual differentiation and thyroid system. BPA caused moderate effects on thyroid system by interference with thyroid receptors but had adverse effects on sexual differentiation disrupting normal gonadal development particularly in males as shown by gross morphological and histological determinations. Zusammenfassung Haushalte und industrielle Direkteinleiter gehören zu den Haupteinträgern von Bisphenol A (BPA) in die Oberflächengewässer des ElbeEinzugsgebietes. Die Emission erfolgt dabei über kommunale Kläranlagen (WWTP), Gemischtwasserkanalisation sowie industrielle Direkteinleiter. Der Gesamteintrag von BPA über die WWTP beläuft sich auf etwa 970 kg/a, der über die Gemischtwasserkanalisation auf 70 kg/a und etwa 510 kg/a entfallen auf zwei industrielle Direkteinleiter im tschechischen Teil der Elbe. Die Retention innerhalb der Oberflächengewässer der Elbe beträgt 790 kg/a bzw. 51%. Xenopus laevis Kaulquappen im Entwicklungsstadium 48 bzw. 51 wurden mit verschiedenen BPA-Konzentrationen im Bereich von 223 ng/L bis 223 µg/L exponiert, um die Wirkungen von BPA auf die Sexualdifferenzierung und das Schilddrüsensystem zu untersuchen. BPA beeinflußte das Schilddrüsensystem über Interaktionen mit dem Schilddrüsenrezeptor nur moderat, zeigte aber adverse Auswirkungen auf die Sexualdifferenzierung durch Störungen bei der Gonadenentwicklung von männlichen Individuen auf morphologischer und histologischer Ebene. © IGB 2007 33 3.1.1.1 Introduction Climate change is recently one of the most important issues in environmental sciences. Many scientific groups are concerned about worldwide temperature and precipitation changes within near future. However, not only rising temperatures and increase of natural disaster are able to modify regions, nutrients, animal or human populations but also environmental pollution in surface water. Since few years especially xenobiotica and recently pharmaceutical compounds are objects of ecotoxicological studies. Xenobiotica contain to the group of “endocrine disruptors” (ED). EDs are compounds which interfere with endocrine systems and disrupt their normal functions within an organism without remarkable toxicity (Colborn et al. 1996, Kloas 2002). Since the 1990`s an increasing pollution of such compounds was noticed for instance in surface waters, agricultural areas, and atmosphere, especially since the analytical methods for detection have been continuously improved. Bisphenol A (BPA) is one of the most common chemicals for production of epoxy resins and polycarbonate plastics (Fig. 1). CH3 HO C OH CH3 Fig. 1: Chemical structure of bisphenol A. BPA is widely used for all kind of products like computer housings, carpets, upholstery, for car paintings and flame retardants such as tetrabromobisphenol A (TBBA). BPA attracted public attention when it has been generally known that it can leach out of plastic baby bottles or cans and migrate into milk and food (Goodson et al. 2004, Braunrath et al. 2005). Since BPA could be detected in diverse human tissues and environmental samples it is nessessary to analyze its biological effects. Clear evidences exist for feminization caused by BPA in snails, fish, and amphibians (Oehlmann et al. 2005, Yokota et al. 2000, Levy et al. 2004) and many publications have shown effects regarding reproduction but some findings are still controversely discussed (Pickford et al. 2003, Yoshida et al. 2004). To get a better understanding of BPA in a prospective perspective it is necessary to assess the general sources and environmental fate of BPA. Therefore the Elbe River system was used as a model. It is the second-largest river system in Germany and one of the largest in central Europe. The biological effects on thyroid system and reproduction were evaluated by means of an amphibian model, the South African clawed toad Xenopus laevis. 3.1.1.2 Material and Methods Bisphenol A emissions and retention The Elbe river system has been investigated for BPA emission and retention. Literature and internet were used to collect informations about chemical properties, and usage of BPA as well as to accumulate data about BPA 34 determination of surface water samples. Mean BPA emissions have been calculated by using the MONERIS model (Behrendt et al. 2003). This model considers following 7 different pathways: particle entry via erosion, dissolved entry via avulsion, basis flow, interflow, tile drainage, atmospheric deposition on water surface areas, sealed urban areas, and point source discharges. Based on informations about inflow and outflow of several WWTP BPA retention for WWTP was calculated. The following retention function was used to create a graph which compares observed BPA concentrations measured along the Elbe main stream and calculated BPA concentrations: C BPA C BPAINPUT 1 1 a º HL 1 HL: Hydraulic loading a= 7.18 BPA determination of water samples of Elbe-river catchment by HPLC Additional to existing environmental data several water samples within the Elbe catchment and tributaries were collected to determine BPA in surface water. Water samples were taken monthly from Spree, Havel, Havel/Spree as well as from WWTP outflow Münchehofe and Erpe. Samples from Wuhle I, II, and Elbe were taken once. 2000 mL water sample were taken from the middle stream and gross filtrated by using glass fiber filters. Each sample was supplemented by 10 g NaCl and concentrated HCl for acidification. RP18 columns were used to concentrate BPA of 1000 mL water sample volume, followed by eluation with acetone. Eluats were dried and resuspended in 1 mL acetonitrile. BPA determination was done by mean of HPLC. Test Animals The animals used for the exposure experiments are coming from an animal stock of the Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany. Adult frogs were induced to spawn by injecting human chorionic gonadotropin (Sigma-Aldrich, Steinheim, Germany) into the dorsal lymph sac according to Kloas et al. (1997). Fertilized eggs and larvae were maintained in 60 L tanks filled with 40 L demineralized water and mixed with 0.25 g/L sea salt (Tropic Marin, Wartenberg, Germany). The water was aerated by using airstones and the water temperature was adjusted to 22 ± 1°C. The pH-value ranged from 7.0 ± 0.5. The light-dark cycle was 12:12 h during the exposure time. Tadpoles were held under these conditions until they reached stages 48 or 51, respectively. Short-term exposure of stage 51 tadpoles Determination of potential effects of BPA on thyroid system was accomplished by exposing tadpoles at stage 51 to BPA alone (100, 250, and 500 µg/L) and to BPA plus 0.1 nM T3 (thyroid hormone (TH)) using a semistatic exposure system (Fig. 2) (n=30, respectively). Stage 51 is particularly qualified for this kind of gene expression determination, because the thyroid gland is not yet functioning. Consequently, no endogenous TH circulate in the blood stream, but several tissues are already competent to respond very © IGB 2007 35 sensitively to exogenous addition of TH by modified gene expression patterns. Test solutions were changed daily. After 24, 48, and 72 h, head tissue was sampled to analyze the thyroid system-specific biomarker thyroid hormone receptor ß (TRß) at the gene expression level. All test chemicals (E2, BPA, T3) were purchased from Sigma (Taufkirchen, Germany). Long-term exposure of stage 48 tadpoles To determine the effects of BPA on morphological parameter (body weight, whole body length), gonadal gross morphology and histology tadpoles at stage 48 were exposed to BPA concentrations ranging from 10-9 to 10-6 M for up to 75 days using a flow through system (Fig. 2). In parallel the natural estrogen 17ß-estradiol (E2) was used as a positive control at 0.2 µg/L. Each treatment contained 4 tanks with 7 L test solution and 25 tadpoles, respectively. At the end of metamorphosis (stage 66), body weight, whole body length and phenotypic sex was determined for all animals. Gonadal tissues were collected for histological analyses. Fig. 2: Design of a semistatistic system and a flow through sytem. Gene expression determination in head tissues Total RNA of head tissues was isolated using the phenolic reagent Trizol (Invitrogen, Karlsruhe, Germany). Diluted RNA was transcribed in cDNA by reverse transcription (RT). Following the amplification of cDNA for EF1a, and TRß genes were carried out as described by Jagnytsch et al. (2005). 3.1.1.3 Results and Discussion Bisphenol A emission The total emission of BPA into the Elbe catchment was found to be 970 kg/a by WWTP, 70 kg/a by sewer systems and 510 kg/a by two industrial discharges in the Czech part of Elbe (Fig. 3). The retention within the surface waters of Elbe is 790 kg/a or 51% The specific emission of 0.24 g/a*inhabitant was calculated. The inhabitant specific discharge out of sewage plants was calculated to be 0.056 g/a*inhabitant. No data were found to atmospheric deposition, particle entry via erosion, dissolved entry via avulsion, basis flow, interflow, and tile drainage. The calculated specific emission of BPA correspond with data 36 found in literature (Fries, 2002), which specify a range 0.013-0.144 g/a*inhabitant. 33% 62% 5% W W TP Sew er System Industrial discharges Fig. 3: Total emission of BPA into Elbe catchment. Using the retention function several BPA concentrations could be calculated for different monitoring stations among the Elbe river. The comparison of these calculated concentrations versus observed BPA concentrations has shown that most of the data were within the 30% deviation but some data were underestimated especially stations downriver of Valy (Fig. 4A). Possible reason for that could be emssions of industrial discharges like Spolchemie and Spolana in the Czech area. Considering these industrial discharges all values were within the 30% deviation of retention (Fig. 4B). A B Fig. 4: Comparison of calculated and observed BPA concentrations among the Elbe river. A without industrial discharges. B with industrial discharges. BPA determination of water samples of Elbe-river catchment BPA was determined in water samples taken from different tributaries of the Elbe catchment. Data are given in table 1. BPA could be detected in all tested water systems. The concentrations ranged from 0-1.5 µg/L. The highest BPA concentration could be measured in WWTP Münchehofe outflow. © IGB 2007 37 Tab. 1: BPA detection in water samples of the Elbe-river catchment. The unit of the given data is ng/L. Water system Oct 06 Nov 06 Dec 06 0 144.3 0 0 127.1 302.7 30.7 112.7 Havel/Spree (Potsdam) 363.5 268.9 20.4 43.6 WWTP Outflow Münchehofe 1062.3 347.0 1002.8 1508.1 Erpe + WWTP Münchehofe 911.8 256.2 627.0 n.d. Elbe (Krippen) 481.9 n.d. n.d. n.d. Wuhle I (Marzahn) n.d. 137.8 n.d. n.d. Wuhle II (Hellersdorf) n.d. 112.2 n.d. n.d. Erpe above WWTP Münchehofe n.d. n.d. n.d. 547.4 Spree (Große Tränke) Havel (Hennigsdorf) Jan 07 Short-term exposure of stage 51 tadpoles TRß-mRNA [CHANGE vs CONTROL] TRß mRNA expression was significantly up-regulated by 0.1 nM T3 already after 24 h and remained elevated over the entire experimental exposure until 72 h. Within 24 hours, T3 treatment caused a 4-fold higher expression of TRß gene in head tissues compared to untreated controls (Fig. 5A). The highest BPA concentration antagonized the T3-induced TRß expression at all sampling points (Fig. 5B). 250 µg/L BPA caused a significant downregulation of the T3-induced TRß expression after 48 h. In the absence of T3, BPA alone did not affect TRß expression. 10 8 SC 100 µg/L BPA + SC 250 µg/L BPA + SC 500 µg/L BPA + SC A 0.1 nM T3 100 µg/L BPA + T3 250 µg/L BPA + T3 500 µg/L BPA + T3 6 *** B *** *** 4 2 24h 48h 72h 24h 48h 72h Fig. 5: Relative TRß-mRNA expression after short-term exposure with BPA. A BPA compared to untreated control. B BPA compared to T3. Long-term exposure of stage 48 tadpoles At the end of metamorphosis, mean weight of tadpoles treated with BPA was increased in a dose dependent manner being significant already at 10-8 M BPA for males and females, respectively (Fig. 6). Mean whole body length of tadpoles exposed to BPA was also increased compared to controls (Fig. 6). This increase was significant at 10-6 M BPA for males and at 10-7 M and 10-6 M BPA for females. At the end of metamorphosis gonads were dissected for histological analyses. The exposure of males to 10-6 M BPA caused remarkable changes in gonadal gross morphology. Histological analyses of these gonads have clearly shown leackages in testicular tissues compared to control animals (Fig. 7A/B). Similar effects could be observed in males which were exposed to the natural estrogen 17ß-estradiol (E2) (Fig. 7C). 38 male female Co * ** *** E2 10-9 10-8 10-7 10-6 Whole body length [mm] Total body weight [g] 1,0 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 male female 21 20 ** *** 19 18 17 16 15 Co E2 10-9 10-8 10-7 10-6 BPA [M] BPA [M] Fig. 6: Total body weight and whole body length after long-term exposure with BPA. At the end of metamorphosis gonads were dissected for histological analyses. The exposure of males to 10-6 M BPA caused remarkable changes in gonadal gross morphology. Histological analyses of these gonads have clearly shown leakages in testicular tissues compared to control animals (Fig. 7A/B). Similar effects could be observed in males exposed to E2 (Fig. 7C). A B C Fig. 7: Hematoxylin-eosin staining of male gonads of juvelile frogs: A untreated control male, B after 10 -6 M BPA treatment, C after E2 treatment. 3.1.1.4 Discussion Biodegradation experiments have demonstrated a half-life of up to 4 days for BPA in river waters (Klecka et al. 2001). Despite it seems to be degraded rapidely after a lag phase it could be shown that BPA is permanently detectable in the Elbe River and several tributaries. Investigations about emissions have shown that mainly WWTP´s and industrial discharges are responsible for the BPA release into the Elbe catchment. A retention rate of 51 % for BPA by WWTP´s was calculated which means the absolute inflow of the WWTP´s must be twice as much. This inflow must be mainly caused by households as well as small and medium sized enterprises. Possible sources of BPA could be toilet paper, © IGB 2007 39 plastic material cleaned in a dishwasher or food rests which are disposed by sewer systems (Gehring 2004, EFSA 2006). Another source of BPA is released from PVC pipes or surface coating agents. Depending on state of the technology the retention of WWTP´s are quite different. Old WWTP´s with trickling filtration and activated sludge barely degrade BPA whereas WWTP´s using membrane filtration, nano-filtration and membrane bioreactors have a BPA elimination rate of at least 75% (Gehring 2004). The amphibian model was used to analyze effects of BPA on the thyroid and reproductive system. Several studies have evaluated that the amphibian Xenopus laevis is a valuable model to determine effects of ED on endocrine system (Opitz et al. 2002, Kloas 2002, Levy et al. 2004). TH produced and released from thyroid gland are essential for different developmental phases during metamorphosis. Interferences of ED with thyroid system can be observed by stimulation or deceleration of metamorphosis in long-term exposure. In this study a short-term exposure with BPA and a combination of TH and BPA was performed to determine effects of BPA on TRß gene expression level. TRß is an early response gene of TH. Within 24 h it responds rapidely to exogenous given TH induction in stage 51 premetamorphic tadpoles. Challenge experiment with BPA and T3 clearly demonstrated a dose response inhibitory action of BPA at concentrations of 250 and 500 µg/L BPA on TH induced gene expression of TRß. Similar inhibitory effects have been observed for TBBA which is the brominated form of BPA and a most commonly used flame retardant (Jagnytsch et al. 2006). The BPA effect was significant but less pronounced compared to that caused by TBBA. These results suggest that compounds with similar chemical structure can have similar properties. Long-term exposure with BPA has shown significant increases in mean body weight and whole body length of juvenile frogs in a dose dependent manner. Studies about effects of BPA on body weight are quite controversial. In several studies it was documented that BPA can cause an increase of single organ weights like uterus and liver in rats and mice (Papaconstantinou et al. 2000). Rubin et al. (2001) has demonstrated the increase of body weight in rat offspring treated by BPA. Further in vivo studies have shown a decrease in mouse and chicken testis weight or body weight probably caused by toxic side effects (Al-Hiyasat et al. 2002, Furuya et al. 2002). However, the natural estrogen E2 was also tested in long-term exposure as a positive control and there was no difference in body weight and whole body length seen suggesting that growth promoting effects of BPA are not induced by estrogenic modes of action but might affect regulation of insulin like growth factors. Investigations of the reproductive system were done by using long-term exposure where the positive control E2 caused 75% feminization. Remaining E2 males have mixed sex gonads or testis with leakages within the tissue. Exposure of males to 10-6 M BPA caused remarkable changes in gonadal gross morphology too. Histological analyses of these gonads also demonstrated leakages in several testicular tissues but less pronounced. From 40 E2 treatment it appeared that feminization of male gonads starts with tissue degradation and disaggregation. After a couple of time, testis changes to mixed gonads which means ovarian and testicular tissue in one gonad until just ovarian tissue is remaining. That means remarkable observation in gross morphology and histology of BPA male gonads could be evidences for beginning feminization procedures. So the tested concentrations of BPA were too low for causing complete feminization. In zebrafish 1820 µg/L BPA caused 32% ovo-testis (Yokota et al. 2000). In summary, BPA action on thyroid system is just moderate resulting in minor competition of BPA and TH on thyroid hormone receptor level or transport binding proteins. Results on gross morphology and histology are not finished yet. But these given results clearly demonstrate that higher BPA concentrations can interfere with the thyroid system probably mediated via its moderate thyroid hormone receptor binding in a competitive manner and also with the reproductive system. Lower concentrations of BPA did not show any remarkable effect. BPA is widely spread in the environment. Especially in regard to animal and human health it is necessary to improve the degradation of such compounds in WWTPs and also to minimize the release of such harmful substances by industries into to surface water. Acknowledgement The research was funded by BMBF (GLOWA-Elbe). The authors thank Wibke Schuhmacher, Ingo Cuppok, Antje Lüder, Bernd Schütze, Björn Hermelink, and Maria Jagnytsch for technical assistance. Special thanks to Marcel Simon and Liane Wieczorek for histological assistance. References AL-HIYASAT, A. S., DARMANI, H., ELBETIEHA, A. M. (2002): Effects of bisphenol A on adult male mouse fertility. Eur J Oral Sci, Vol. 110, 163-167. BEHRENDT, H., CONSTANTINESCU, L.T., CVITANIC, I., DRUMEA, D., JABUCAR, D., JURAN, S., PATAKI, B., SCHREIBER, H., SNISHKO, S., ZESSNER, M. (2003): Nährstoffeinträge und –frachten im Flusssystem der Donau - Ergebnisse einer flussdifferenzierten Modellanalyse: Nutrient inputs and loads in the Danube River system – Results of a river system oriented model analysis. ÖWAW., Heft 9-10, 1-7. BRAUNRATH, R., PODLIPNA, D., PADLESAK, S., CICHNA-MARKL, M. (2005): Determination of bisphenol A in canned foods by immunoaffinity chromatography, HPLC, and fluorescence detection. J Agric Food Chem, Vol. 53, 8911-8917. COLBORN, T., Dumanoski, D., Myers, J. P. (1996): Our stolen future. Little Brown & Co., London. EFSA. (2006): Opinion of the scientific panel on food additives, flavourings, processing aids and materials in contact with food on a request from the commssion related to 2,2-bis(4-hydroxyphenyl)propane (bisphenol A). The EFSA Journal, Vol. 428, 1-75. © IGB 2007 41 FURUYA, M., SASAKI, F., HASSANIN, A. M. A., KUWAHARA, S., TSUKAMOTO, Y. (2002): Effects of bisphenol A on the growth of comp and testes of male chicken. The Canad J of Veterenary Res, Vol. 67, 68-71. GEHRING, M. (2004): Verhalten der endokrin wirksamen Substanz Bisphenol A bei der kommunalen Abwasserentsorgung. Doktorarbeit. http://rcswww.urz.tudresden.de/~gehring/deutsch/dt/mitar/ge/dige_lic.pdf GOODSON, A., ROBIN, H., SUMMERFIELD, W., COOPER, I. (2004): Migration of bisphenol A from can coatings - effects of damage, storage conditions and heating. Food Additives Contaminants, Vol. 21, 1015-1026. JAGNYTSCH, O., OPITZ, R., LUTZ, I., KLOAS, W. (2006): Effects of tetrabromobisphenol A on larval development and thyroid hormone regulated biomarkers of the amphibian Xenopus laevis. Environ Res, Vol. 101, 340-348. KLOAS, W. (2002): Amphibian as a model for the study of endocrine disruptors. Int Rev Cytol, Vol. 216, 1-57. LEVY, G., LUTZ, I., KRÜGER, A., KLOAS, W. (2004): Bisphenol A induces feminization in Xenopus laevis tadpoles. Environ Res, Vol. 94, 102-111. OEHLMANN, J., SCHULTE-OEHLMANN, U., BACHMANN, J., OETKEN, M., LUTZ, I., KLOAS, W., TERNES, T. A. (2006): Bisphenol A induces superfeminization in the Ramshorn snail Marisa cornuarietis (Gastropoda Prosobranchia) at environmentally relevant concentrations. Environ Health Prospective, Vol. 114, 127-133. OPITZ, R., LEVY, G., BÖGI, C., LUTZ, I., KLOAS, W. (2002): Endocrine disruption in fish and amphibians. Recent Res Devel Endocrinol, Vol. 3, 127-170. YOKOTA, H., TSURUDA, Y., MAEDA, M., OSHIMA, Y., TADOKORO, H., NAKAZONO, A.,HONJO, T., KOBAYASHI, K. (2000): Effects of bisphenol A on the early live stage in Japanese medaka (Oryzias latipes). Environ Toxicol and Chem, Vol. 19, 1925-1930. PAPACONSTANTINOU, A. D., UMBREIT, T. H., FISHER, B. R., GOERING, P. L., LAPPAS, N. L., BROWN, K. M. (2000): Bisphenol A-induced increase in uterine weight and alterations in uterine morphology in ovariectomized B6C3F1 Mice: Role of the estrogen receptor. Toxicol Sci, Vol. 56, 332-339. PICKFORD, D. B.., HETHERIDGE, M. J., CAUNTER, J. E., TILGHMAN HALL, A., HUTCHINSON, T. H. (2003): Assessing chronic toxicity of bisphenol A to larvae of the African clawed frog (Xenopus laevis) in a flow-through system. Chemosphere, Vol. 53, 223-235. RUBIN, B. S., MURRAY, M. K., DAMASSA, D.A., KING, J.C., SOTO, A. M. (2001): Perinatal exposure to low doses of bisphenol A affects body weight, patterns of estrous cyclicity, and plasma LH level. Environ Health Persp, Vol. 109, 675-680. YOSHIDA, M., SHIMOMOTO, T., KATASHIMA, S., WATANABE, G., TAYA, K., MAEKAWA, A. (2004): Maternal Exposure to low doses of bisphenol A has no effects on development of female reproductive tract and uterine carcinogenesis in Donryu rats. J of Reprod and Develop, Vol. 50, 349-360. 42 3.2 Research Topic 2 Forschungsschwerpunkt 2 Processes at interfaces Prozesse an Grenzflächen © IGB 2007 43 44 H ILT , S., S CHÖNFELDER ,I., R UDNICKA , A., C ARLS , R., N IKOLAEVICH , N., S UKHODOLOV , A., E NGELHARDT , C. 3.2.1 Reconstruction of pristine morphology, flow, nutrient conditions and submerged vegetation of lowland River Spree (Germany) from palaeomeanders Rekonstruktion der Referenzbedingungen der Unteren Spree hinsichtlich Morphologie, Abfluss, Nährstoffkonzentrationen und Unterwasservegetation aus Paläomäandern Key words: bankfull palaeodischarge, diatoms, macrofossil remains, macrophytes, nutrient concentrations, reference conditions, water framework directive, lowland river Abstract The European Water Framework Directive requires the definition of reference conditions for each type of surface waters as a base to establish a classification system in which deviations from this high quality status must be determined. In order to reconstruct pristine conditions in the lower River Spree we investigated palaeomeanders using palaeohydrological and palaeolimnological methods. Reconstructions show narrower and shallower channels for the undisturbed lower Spree as compared to recent conditions. Flow velocities and discharge at bankfull stage have been smaller in reconstructed sub-fossil channels and flow variability was higher. Diatominferred total phosphorus concentrations indicate eutrophic to hypertrophic conditions and suggest naturally slightly lower nutrient levels than today. These past nutrient conditions, morphology and large numbers of macrofossil remains indicate optimum growth conditions for submerged macrophytes growth. Zusammenfassung Die EU-Wasserrahmenrichtlinie fordert für jeden Gewässertyp die Definition von Referenzbedingungen als Grundlage für ein Klassifizierungssystem, das auf Abweichungen von diesem Status höchster Qualität beruht. Um die Referenzbedingungen der Unteren Spree zu rekonstruieren wurden Paläomäander mittels paläohydrologischer und paläolimnologischer Methoden untersucht. Die unbeeinflusste Untere Spree war im Vergleich zu heutigen Bedingungen enger und flacher. Die Fließgeschwindigkeiten und der Abfluss im bordvollen Zustand waren geringer und die Variabilität der Fließgeschwindigkeiten höher. Die über Diatomeen-Analysen rekonstruierten Gesamtphosphorkonzentrationen waren etwas geringer als die aktuellen und indizieren eutrophe bis hypertrophe Bedingungen für den Referenzzustand. Eutrophe Bedingungen sowie die rekonstruierte Morphologie und große Mengen makrofossiler Reste submerser Makrophyten deuten auf optimale Bedingungen für die Entwicklung submerser Makrophyten. © IGB 2007 45 3.2.1.1 Introduction The European Water Framework Directive (Directive 2000/60/EC of the European Parliament), potentially the most significant piece of legislation ever to be enacted in the interest of conservation of fresh and saline ecosystems, requires the restoration of aquatic habitats to a so-called good ecological status. For each ecotype, reference conditions must be defined as a base to establish a classification system in which deviations from this pristine status must be determined. Establishment of reference conditions from existing sites is difficult as there are few, if any, such sites available in Europe (Moss et al. 2003). Thus, there is a need to determine the reference conditions, for example with palaeoecological reconstructions. Reconstructions increase in significance when multiple palaeoindicators are used (Brown 2002), e.g. when the reconstruction relies on both palaeohydrological and palaeolimnological parameters. The following study was carried out to reconstruct the reference conditions regarding hydromorphology, flow characteristics, bankfull discharge, nutrient conditions and the aquatic vegetation in the lower River Spree (North-eastern Germany). Palaeomeanders suitable for these reconstructions were identified using aerial infrared photographs, sedimentological analyses of sediment cores from transects across palaeomeanders and geodetic surveys. For the reconstruction of the bankfull palaeodischarge, a model was developed that includes a parametrization of the velocity distribution in the recent river channel under local conditions of flow resistance, thus, avoiding the empirical formulas commonly used in palaeohydrological reconstruction. Over longer time scales (decades and centuries) a meandering river forms a channel, which is able to transport the amount of water and sediment supplied by the catchment basin (Leopold 1994). This quasi-equilibrium between discharge and channel morphology of pristine rivers is the prerequisite for the reconstruction of hydrological characteristics using palaeochannels. The relationship between the reconstructed channel morphology and the unknown palaeodischarge is often defined through a single, dominant discharge that produces the observed channel. It is often assumed to be close to bankfull (Lauer & Parker 2006). Thus the key to determining discharge under undisturbed flow conditions (hydraulic reference conditions) is the reconstruction of the only water stage that leaves a clear trace in the morphology of a river channel, the stage of the so-called bankfull discharge (Rotnicki 1991). Palaeolimnological reconstructions can be used when sediments accumulate in continuous sequences, for example, in deep lakes (e.g. Lotter 2001) and often also in shallow lakes (e.g. Bennion et al. 2001). In rivers, which have high sediment dynamics, continuous sedimentation is limited to low current areas (e.g. deposition zones at the inner bank of the meander loop). Thus, cores drilled across a meander apexes would (at the inner bank) contain settled material that, at least partly, consists of autochthonous microand macrofossils from the flowing river. The succession of any meandering river further emphasises that meander loops are characterized mainly by 46 expansion until the meandering pattern is destroyed by a cut-off. Once abandoned these former parts of the main river channel accumulate sediments that still contain river-borne material that enters the oxbow lake during flooding events, but an increasing share of material characterizing the oxbow-lake-stage. The latter can be distinguished from the flowing-riverstage by its sediment texture and changes in the phytoplankton and macrophytes species composition. Macrofossils of palaeomeanders only partly originate from the main river, but can be used to reconstruct pristine river conditions when used in combination with information on hydromorphological conditions and nutrient concentrations. 3.2.1.2 Material and Methods In order to find suitable palaeomeanders for the reconstruction of pristine hydrological and limnological conditions of the lower River Spree we used colour-infrared (CIR) aerial photographs of the Drahendorfer Spree. In a first step we selected all palaeomeanders with exact delimitation and a complete meander bend. Afterwards sediment cores were taken in the apex, and meanders showing a clear boundary between the active channel documented by mineral material (especially sand and gravel) and the silting up material (muds, peat) were selected for further investigation. Subsequently, cross profiles were determined by sediment core drillings in the apex domain of the selected meanders. Palaeomeanders suitable for the calculation of the cross-sectional area at bankfull stage were dated and those representing periods with low anthropogenic impact used for the analysis of diatoms and macrofossil remains to reconstruct nutrient concentrations and the colonization with aquatic macrophytes, respectively. Detailed information about the methodology can be found in Hilt et al. (2007). Fig. 1:. Reconstructed vertical cross-section and bankfull stage of investigated palaeomeander and approximation of the detected cross-profile by a parabolic function © IGB 2007 47 3.2.1.3 Results TN :T P Diatom Zone (m g* l -1) DI - DI -T N 0 Ac hn a Fr nth a e Ac gila s h hn ria un Na a ca ga vic nth pu ric e a Au ula s m cina (G la pu in va run co p u o se ula tiss r. m w) ira K im es G Au gr ützi a K ole run la ng üt pt ow co an z se ul va in a (R at ira sm a ( r. p g va ab am Eh up r. en al lb u m h re bi en gu nb la inu ors th a ( er tis t) Au ic G g) sim Ra la Fr r u Si Co co ag no a ben m ila c s w on ho Cy co eira ) r i se rs Si as clo nei la t m n pp G s s e se on om te pl vis . ns se Fr ph ph ace sim u n ag o an n a la t n to St ila e os ul (G a e r m r M pha ia u a p dub var uno el n ln a iu . li w o o a rv s n ) G sira disc (Ni ulu (Fri eat Kra om v u tzs m ck a m c (K e) (E m p ar s G hon ians neo h ) L ütz Ro hre er o e A a a in u n Fr mph ma gastra nge g ) Knd ber g) ag o -B ü m rd e Va # ilar nem icr h a Ha ert tzin nH of ia a op ka alo g v ta ca s eu ns t v ar xa p ar us K rc s a uc co üt on r. . pa k u zin in ph & ln rvu ao a DI g a H -T th gu ick se lum er s G P el ns (µ v r u ar eg g* la s . or l -1) to y Of 15 palaeomeanders identified from aerial photographs of the floodplain of the Drahendorfer Spree, eight were suitable for the reconstruction of hydromorphological characteristics (see Fig. 1 in Hilt et al. 2007). Following dating, three sites (in downstream order D5, D7, D1) were chosen for further calculations as they represent periods of low anthropogenic impact. Channel width at bankfull stage varied between 16 and 21.5 m and mean depth between 0.64 and 0.99 m. A flow model was developed for the reconstruction of bankfull flow characteristics and discharge of the lower River Spree (for details see Hilt et al. 2007). This model was applied to the surveyed morphometrical data of the palaeomeanders D5, D7, and D1. Their cross-sections were approximated by a parabolic function (Fig. 1). Using the bankfull stage, flow velocity at each point of the cross-section was calculated using a closed system of analytical equations (Hilt et al. 2007). Integration of the calculated flow velocities over the cross-sectional area results in the mean flow velocity. Calculated bankfull discharges varied between 5.5 and 10.3 m³ s-1 (Table 1). 10 Core depth (cm) 20 30 40 II 50 60 70 80 90 I 100 0 20 0 20 40 20 0 20 Relative diatom abundance (%) 0 20 20 80 120 30 90 150 0.8 2.4 10 20 30 Fig. 2: Relative abundance of important diatom taxa, number of differentiated taxa, diatominferred total phosphorus (DI-TP), DI-total nitrogen (TN) and DI-TN:TP in a sediment core of palaeomeander D5 of the Drahendorfer Spree. Diatom-based reconstructions were performed for the core of palaeomeander D5. The diatom assemblage can be divided into two zones (Fig. 2). Zone I (105-85 cm, ~1100–500 BC) was characterized by benthic Achnanthes hungaria (Grunow) Grunow (3-13%), Achnanthes minutissima Kützing var. minutissima (1-5%) and Navicula pupula Kützing var. pupula (05%), as well as tychoplanktonic Fragilaria capucina var. mesolepta (Rabenhorst) Rabenhorst (1-6%). Zone II (80-1 cm, ~500 BC to 2003) was characterized by increased abundances of planktonic Aulacoseira ambigua (2-23%) and Aulacoseira granulata (4-34 %), as well as taxa typically found in bogs, such as taxa from the genus Eunotia and Pinnularia. Additionally, small, benthic Fragilaria spp. (F. brevistriata Grunow, F. construens (Ehrenberg) Grunow f., 48 construens, F. construens f. binodis (Ehrenberg) Hustedt and F. construens f. venter (Ehrenberg) Hustedt), Gomphonema micropus Kützing, Gomphonema sarcophagus Gregory, as well as planktonic Aulacoseira laevissima (Grunow) Krammer and tychoplanktonic Melosira varians Agardh, which occurred in low abundances in zone I (together < 18%), comprised 11-32% of the assemblage in zone II. Diatom-inferred total phosphorus (DI-TP) increased from 59-73 µg L-1 in zone I to 59-98 µg L-1 in zone II, while DI-TN hardly changed throughout the core (median zone I = 1.3 mg L-1, median zone II = 1.5 mg L-1) (Fig. 2). Macrofossil remains of both, submerged or floating-leaved plants (seven taxa) and emergent aquatic plants (eight taxa) were found at the base of palaeomeander cores D5, D7 and D1. For example; seeds of the submerged genus Ranunculus sect. Batrachium were present in all three meanders. In contrast, remains of submerged or floating-leaved species were absent in the upper sediments (except for Lemna spp.; core D5, zone II in Fig. 3), whereas most emergent species were found throughout the core (Fig. 3). Floating Emergent Po ta m og et on ob tu si fo liu s R an St unc ra ul tio us te s N s ec ym al t. oi B de a N ph up ae s tra ch Le har a a iu m lu lba m Al na tea is sp m p a . pl an ta go O -a en qu an at t he ic M a en aq th u a a aq tica Ly au co tic C pu ar s a ex eu sp rop Ju p. a eu nc s Sc us irp sp us p. sp p. Submerged 0 10 Core depth (cm) 20 30 40 50 60 70 80 90 100 110 0 20 40 60 0 0 20 0 0 0 20 40 20 20 0 20 Macrofossil remains (n * 100 ml-1) Fig. 3: Macrofossil remains in a sediment core of palaeomeander D5 of the Drahendorfer Spree. 3.2.1.4 Discussion The palaeomeanders investigated in our study represent reference conditions of the lower River Spree. AMS dating suggests that the sediments at the base of three investigated cores (D5, D7 and D1) represent the late Subboreal/early Sub-atlantic, a time of low anthropogenic impact in the catchment of the River Spree (Bork et al. 1998, Driescher & Behrendt 2002). The pristine lower River Spree had narrower and shallower channels compared to the recent river (Table 1). Both mean flow velocities at bankfull stage were slower and flow variability was higher in the reconstructed subfossil channels of the Lower Spree. © IGB 2007 49 Tab. 1: Hydrological characteristics at bankfull discharge of the recent (meander near Neubrück) and the pristine lower River Spree (mean of palaeomeanders D5, D7, D1). Discharge Meander slope Mean width at bankfull stage Mean depth at bankfull stage Mean flow velocity Local characteristic (shear) velocity Recent Reconstructed 51.7 m³ s -1 0.00005 35.2 m 1.63 m 0.9 m s -1 2.8 cm s -1 8.2 m³ s -1 0.00008 19.6 m 0.79 m 0.53 m s -1 2.4 cm s -1 Palaeohydrological reconstructions are all subject to error, because of limited or unreliable data or simplifications inherent to model formulas (Williams 1988). Our newly derived approach to identify suitable palaeomeanders for reconstructions using aerial photography in combination with geomorphology resulted in rather robust hydromorphological data sets. The estimation of bankfull discharge by planar parameters of a palaeomeander such as width (e.g. Durys (1977) formula) or width and sinuosity (e.g. Rundquists (1975) formula) is mostly less accurate (Knighton 1998) than that from a combination of planar, cross-sectional parameters, and slope (e.g. Williams` (1978) formula). Hydraulically based equations for discharge as those developed by Grishanin (1979) or Rotnicki (1991) additionally involve the flow resistance to which the velocity (and thus the discharge) is strongly related. Our model calculates the flow velocity distribution over a bankfull cross-sectional area directly, using a parametrization developed from field data in the recent Drahendorfer Spree. Discharge in this model yields from the mean cross-sectional velocity and the area at bankfull discharge. Our bankfull discharge reconstruction is in good agreement with the more complex models of Williams (1978) and Rotnicki (1991). Our model is more sensitive to the local slope of the meander than the most advanced models of Williams (1978) and Rotnicki (1991), where slope occurs with the exponent 0.28 and 0.5, respectively. To illustrate the uncertainty of the modelled bankfull discharge, the maximum possible (slope of the floodplain) and the minimum possible slope (detected slope of the recent Drahendorfer Spree measured in field) was used instead of slope calculated by the equation for meandering rivers (Hilt et al. 2007). The resulting maximum bankfull discharge values for D1, D7, D5 are then 11.2 m³ s-1, 5.8 m³ s-1 and 9.3 m³ s-1, respectively; the minimum values are 8 m³ s-1, 3.9 m³ s-1, and 6.3 m³ s-1, respectively. When these three palaeomeanders are considered, the modelled mean bankfull discharge is 8.2 m³ s-1 (6.1-8.7 m³ s-1, Table 1). In sand-bed rivers, the grain roughness (which is expressed by Manning´s number in Rotnicki`s formula) is often less important than other components of the total flow resistance resulting from frictional effects at the bank and the bed of the channel. The flow model presented here includes these effects and should therefore minimize the error usually associated with reconstructed bankfull discharge. The difference between the recent (~52 m³ s-1) and the reconstructed (~8 m³ s-1) bankfull discharge of the Lower River Spree can only partly be explained by the current additional input of mining water into the Spree (~14 m³ s-1). Similarly, climatic conditions in Central Europe did not change 50 dramatically during the last 3000 years (Lamb 1977, Glaser 2001) and can therefore not fully explain the discharge increase either. For example, using a macrophysical runoff model driven solely by climatic data, Bryson et al. (2003) simulated a less than 10% greater discharge of Central European Rivers in the middle Holocene than today. In contrast, many examples indicate that river discharge may greatly increase when natural vegetation is cleared (Bosch & Hewlett 1982, Sahin & Hall 1996, Foley et al. 2005) as deforestation alters both the balance between rainfall and evapotranspiration and the runoff response of a drainage basin. In Germany, the forested area declined from 90% in the 6th century to 15% in the early 14th century (Schmidtchen & Bork 2003). Furthermore, channelization, bank protection and river regulation measures, typical for the River Spree (Driescher 2002), also increase flow velocity and transport capacity of a river. For example, bankfull discharge of the River Raba (Poland) increased by a factor of 2.4 after channelization due to reduced floodplain storage and greater concentration of water within the channel zone (Wyzga 1996). Therefore, land-use changes and river straightening were probably responsible for most of the inferred discharge changes in the lower River Spree. Diatom assemblages in zone I of the investigated core of palaeomeander D5 are assumed to represent reference conditions of the River Drahendorfer Spree for the following reasons: 1) Dating techniques suggest that zone I represents ~1100-500 BC, a time in which the study area was hardly inhabited (Driescher & Behrendt 2002). Therefore, anthropogenic impact on the water quality was probably very low or absent in zone I. 2) Taxa present in diatom zone I are typical taxa from the River Drahendorfer Spree. For example, in the River Drahendorfer Spree many planktonic diatoms, such as Aulacoseira laevissima, originate in Lake Schwielochsee (I. Schönfelder, unpublished data), which is located just 12 km upstream of the study site. These taxa were abundant in zone I. Additionally, taxa typically reflecting oxbow rather than river conditions were almost absent in zone I, but common in zone II, such as taxa typically found in bogs. Overall, diatominferred chemical water conditions in zone I suggest that the Drahendorfer Spree had naturally eutrophic to hypereutrophic nutrient levels. Still, reference TP levels (~ 62 µg L-1) are lower and reference TN levels (~ 1.3 mg L-1) slightly lower than today (94 µg L-1 and 1.8 mg L-1, respectively). Naturally high nutrient levels could be due to the geology of the catchment area (Driescher 2002). Another possible source of nitrogen is Lake Schwielochsee, which probably had naturally favourable conditions for nitrogen-fixing blue-green algae during the summer months (I. Schönfelder, unpublished data). Similarly high or even higher nutrient reference conditions were inferred for flushed lakes and river reaches both up- and downstream of Drahendorfer Spree (Hilt et al. 2007) as well as other lakes in the vicinity and in River Havel (Schönfelder 1997). The reconstructed low water depth (Table 1), diatom-inferred eutrophic to hypertrophic conditions and large numbers of macrofossil remains © IGB 2007 51 indicate optimum growth conditions for submerged macrophytes in the pristine lower River Spree. Due to the shallow water and the small river width (Table 1), the main limiting factor for submerged macrophytes in the pristine lower River Spree has probably been shading by bankside trees (Dawson & Kern-Hansen 1978). Higher flow variability generally results in a less uniform colonization and higher species diversity (Hey et al. 1994). In addition to submerged species of the genera Ranunculus sect. Batrachium (Water-crowfoot) and Potamogeton (pondweeds) that were detected by seeds, other species probably also occurred under pristine conditions. Birks (2000) already pointed out that lack of seed representation may result from vegetative production for survival. In reaches with higher flowing velocities and water depths above 1 m, a community dominated by River Watercrowfoot (Ranunculus fluitans) may have occurred, whereas slow flowing stretches were probably dominated by species-rich Sparganium emersum communities comparable to the present vegetation in the River Müggelspree (Schulz et al. 2003). Similar to the diatoms, all submerged and emergent macrophyte species detected indicate eutrophic conditions (Krausch 1996). 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MOSS, B., STEPHEN, D., ALVAREZ, C., BECARES, E., VAN DE BUND, W., COLINGS, S.E., VAN DONK, E., DE EYTO, E., FELDMANN, T., FERNANDEZ-ALAEZ, C., FERNANDEZ-ALAEZ, M., FRANKEN, R.J.M., GARCIA-CRIADO, F., GROSS, E.M., GYLLSTRÖM, M., HANSSON, L.A., IRVINE, K., JÄRVALT, A., JENSEN, J.P., © IGB 2007 53 JEPPESEN, E., KAIRESALO, T., KORNIJOW, R., KRAUSE, T., KÜNNAP, H., LAAS, A., LILL, E., LORENS, B., LUUP, H., MIRACLE, M.R., NOGES, P., NOGES, T., NYKÄNEN, M., OTT, I., PECZULA, W., PETERS, E.T.H.M., PHILIPS, G., ROMO, S., RUSSELL, V., SALUJOE, J., SCHEFFER, M., SIEWERTSEN, K., SMAL, H., TESCH, C., TIMM, H., TUVIKENE, L., TONNO, I., VIRRO, T., VICENTE, E., WILSON, D. (2003): The determination of ecological status in shallow lakes – a tested system (ECOFRAME) for implementation of the European Water Framework Directive. Aquatic Conservation: Marine and Freshwater ecosystems, 13, 507-549. ROTNICKI, K. (1991): Retrodiction of paleodischarges of meandering and sinous alluvial rivers and its paleoclimatic implications. In: STARKEL, L., GREGORY, K.J., THORNES, J.B. (eds.). Temperate Palaeohydrology: Fluvial Processes in the Temperate zone During the Last 15,000 Years. John Wiley & Sons, Chichester, 430 – 471. RUNDQUIST, L.A. (1975): A classification and analysis of natural rivers. Colorado State University, Fort Collins, Colorado, PhD Thesis. SAHIN, V., HALL, M.J. (1996): The effects of afforestation and deforestation on water yields. Journal of Hydrology, 178, 293-309. SCHMIDTCHEN, G., BORK, H.R. (2003): Changing human impact during the period of agriculture in Central Europe: the case study Biesdorfer Kehlen, Brandenburg, Germany. In: LANG, A., HENNRICH, K., DIKAU, R. (eds.). Long term hillslope and fluvial system modelling. Springer Verlag, Berlin, 183-200. SCHÖNFELDER, I. (1997): Eine Phosphor-Diatomeen-Relation für alkalische Seen und Flüsse Brandenburgs und ihre Anwendung für die paläolimnologische Analyse von Auensedimenten der unteren Havel. Diss. Bot., 283, 1-48. SCHULZ, M., RINKE, K., KÖHLER, J. (2003): A combined approach of photogrammetrical methods and field studies to determine nutrient retention by submersed macrophytes in running waters. Aquatic Botany, 76, 17-29. WILLIAMS, G.P. (1978). Bankfull discharge of rivers. Water Resources Research, 14, 1141-1158. WILLIAMS, G.P. (1988): Paleofluvial estimates from dimensions of former channels and meanders. In: Baker, V.R., Kochel, R.C., Patton, P.C. (eds.): Flood geomorphology. Wiley, Chichester, 321-334. WYZGA, B. (1996): Changes in the magnitude and transformation of flood waves subsequent to the channelization of the Raba River, Polish Carpathians. Earth Surface Processes and Landforms, 21, 749-763. 54 W IESE , B., N ÜTZMANN , G. 3.2.2 Infiltration of surface water into groundwater under transient pressure gradients Infiltration von Oberflächenwasser in den Grundwasserleiter bei instationären Druckgradienten Key words: surface water, groundwater, bank filtration, infiltration, leakage coefficient, numerical modelling Abstract Several kinds of managed aquifer recharge techniques provide very good purification of surface water since more than 100 years. In order to maintain a reliable supply of clean water, they are becoming increasingly popular all over the world. Especially bank filtration methods require low technical effort. Exemplarily, at a test site at Lake Tegel, Berlin, Germany, the hydraulic processes of infiltration are modelled. By means of 3D long term regional and transient hydraulic modelling it was detected that the existing approaches for determining the leakance induce large errors in the water balance and describe the infiltration zone insufficiently. The leakance could be identified to be triggered by the groundwater table, causing air exchange and intrusion of atmospheric oxygen, which reduces clogging by altered redox conditions by at least one order of magnitude. This causes that changes of the groundwater table are mitigated much more than previously assumed. Taking these findings into account, a transient water balance is determined and bank filtration ratios are quantified. Zusammenfassung Seit mehr als 100 Jahren wird Oberflächenwasser mit verschiedenen Verfahren versickert, wobei sich dessen Qualität stark verbessert. Sie finden zunehmend weltweit Anwendung, um eine zuverlässige Versorgung mit sauberem Trinkwasser zu gewährleisten. Insbesondere die Uferfiltrationstechnik erfordert nur einen geringen technischen Aufwand. Am Beispiel eines Untersuchungsgebiets am Tegeler See in Berlin werden die hydraulischen Prozesse modelliert. Die regionale, instationäre und 3-dimensionale Modellierung eines langen Zeitraums zeigt, dass die bisher verwendeten linearen Ansätze zur Beschreibung der Durchlässigkeit der Kolmationsschicht sowohl die infiltrierten Wassermengen als auch die Infiltrationsprozesse nur unzureichend wiedergeben. Grundwasserpiegelschwankungen werden stärker als bisher angenommen gedämpft. Als Folge dieser Wasserspiegelschwankungen wird die Bodenluft in der ungesättigten Bodenzone ausgetauscht und Sauerstoff eingetragen. Auf diese Weise erhöht sich die Durchlässigkeit der Kolmationsschicht um mindestens eine © IGB 2007 55 Größenordnung. Auf Grundlage dieser Ergebnisse wurden eine instationäre Wasserbilanz aufgestellt und die Uferfiltratanteile bestimmt. 3.2.2.1 Introduction During bank filtration horizontal or vertical collector wells induce a hydraulic gradient which causes infiltration of surface water into the aquifer. During the underground passage mechanical as well as biogeochemical reactions proceed, substantially improving the water quality regarding suspended solids, algae, pathogens and other bacteria, algal toxins, dissolved organic carbon, nitrate, organic pollutants and pharmaceutical residues. These constituents are eliminated or significantly reduced, peak concentrations of the surface water are mitigated. In Europe, predominatly river bank filtration is used (Doussan et al. 1993, Grischek et al. 2003), and especially in lowland regions, where shallow lakes form a part of river system, bank filtration was operated also at lakes (Miettinen et al. 1997, Fritz et al. 2004). For the quantitative and qualitative management of bank filtration systems, flow velocities, travel times and infiltration capacities need to be known. The latter is the crucial point because it depends on well operation and hydraulic resistance of lake bed sediments, also affecting by clogging. The permeability of river beds is known to be time variable because of continuous change by shear stress, bed load transport, discharge, water level fluctuation and other factors (Huettel et al. 2003). Exchange coefficients between lakes and groundwater are not reported to be time-variant, neither under natural nor anthropogenic conditions. The bank filtration system at Lake Tegel, NW of Berlin, is characterized by highly transient well operation whereby hydraulic head differences between lake and groundwater show strong temporal variations. To model the groundwater response, however, the dynamic infiltration from surface water into the adjacent aquifer cannot be simulated assuming a linear relationship, where the water fluxes across the aquatic sediment surface is proportional to the hydraulic head differences, and the unknown factor is defined as leakage coefficient (Bear 1972). The observed highly variable infiltration dynamics reveal that typically used boundary conditions of third order or something like that are insufficient. Previously applied nonlinear approaches regarding depthdependent changes of permeability and temperature effects also could not describe the mechanisms (Schubert 2002, Lin et al. 2003, Holzbecher et al. 2006). They do neither quantify the mass transfer fluxes nor its spatial distribution. Here a gap in mechanistic understanding and modelling approaches of exchange between surface water and groundwater exists. The present study discussed infiltration behaviour of a lake bank filtration system, showing transient infiltration dynamics on different temporal and spatial scales. Different assumptions about mathematical formulation and distribution of leakage are made and expressed in four differing paramatrizations. The goodness of tempospatial infiltration characteristics is assessed by comparison with time-series of hydraulic heads, 56 in situ infiltration measurements and geochemical data. The comprehensive interpretion shows that infiltration can only be described sufficiently when leakage is modelled transiently, considering the interaction of water flow, air flow in the unsaturated zone and biological processes in the clogging layer. 3.2.2.2 Material and Methods Investigation area The investigated area is located at Lake Tegel in the NW of Berlin, Germany (Figure 1). Here, Berlin largest waterworks is pumping about 45 million m3 per year from 6 well fields around the lake and from two on the islands. This affects groundwater flow within an area of 50 km2. Fig. 1: Lake Tegel and adjacent well fields. Small red dots indicate vertical collector wells, the red circle on Scharfenberg indicates a horizontal collector well. GWA denotes groundwater recharge ponds. The two upper aquifers in the model domain as well as Lake Tegel itself are formed during the Saale ice-age. The 1st aquifer is unconfined consists of fine to coarse sand, has a thickness of about 15 m and a hydraulic conductivity of about 3.5*10-4 m/s. The 2nd and main aquifer also consists of fine to coarse sand with a thicknes between 25 to 50 m, covered by a glacial till of about 4 m thickness. The hydraulic conductivities range from 2*10-4 m/s to 5.5*10-4 m/s. In this 2th aquifer the vertical collector wells are screened. Both aquifers are hydraulically well connected. Hydraulic Modelling The model domain is depicted in Figure 2, including the two upper aquifers, where the waterweorks abstracts raw water. In order to focus on the © IGB 2007 57 infiltration process at the Lake Tegel and to avoid a large-scale regional model set-up, the size of the model is reduced through the appropriate choice of boundary conditions, which are discussed in detail in Wiese (2006). Simulation is carried out between January 1st 1998 and April 30th 2005. The first 90 days are simulated steady state; afterwards simulation is transient with weekly discretization. Spatially the model is discretized by 7 layers, with a thickness between 4 m and 8 m, the horizontal cell size varies between 5 * 5 m close to the transect to 15 * 50 m next to the boundary. The model is set up under PMWinPro7 (WebTech360 2003) with the flow model of MODFLOW (Harbaugh et al. 2000). Fig. 2: Top view on the model domain with boundary conditions. The coloured symbols indicate observation wells. Parameter estimation The focus of the model calibration is set to an adequate description of the leakage because this study showed that it is the most sensitive parameter. As shown in Figure 3, simulation of hydraulic head time series doesn’t match the observed ones using overall constant leakage coefficients. With high leakage in shallow water decreasing to zero at 5 m depth, the model calculates too large infiltration rates or is entirely drained. Therefore, the model is parametrized as follows. Four scenarios (cases) are derived based on different assumptions about the description of infiltration (Wiese 2006). For case 1 to case 3, the spatially distribution of the leakage is defined by 8 zones (or parameters), each comprising an elevation interval of 1 m between 25 m and 32 m NN, see Figure 4. 58 Fig. 3: Observed and measured piezometric heads at observation well TEG050 with two temporally and spatially constant leakage coefficients. In case 2 and 3 their values are additionally multiplied by a timedependent function, so that the temporal and spatial distribution of the leakage could be modelled. For case 4 it is assumed that the leakage is triggered temporally and spatially by the thickness of the unsaturated zone below the infiltration area. Thus, the numbers of parameters to be fitted are different for each case: 9 parameters for case 1, 11 parameters for case 2, 54 parameters for case 3 and 5 parameters for case 4. Fig. 4: Spatial distribution of the depth dependent leakage. Each colour represents one parameter. Due to the great impact of infiltration, the hydraulic conductivity of the aquifer is insensitive to calibration. The hydraulic model has been calibrated using PEST (Doherty 2003). Because measurement errors are not available and the impact of the structure of observations is much higher, each single hydraulic head measurement is weighted according to the time for which it is © IGB 2007 59 representative, divided by the standard deviation of all observations of the particular piezometer. Transport modelling Transport simulations are carried out in order to show the plausibility of the concept of temporal variant leakage. Due to restricted data and travel times they are carried out only within a small area of the flow model domain (see Figure 2, around transect in the center of the area including the observation wells 3312 and 3313). The species 18O and temperature are modelled. 18O is an ideal tracer and data are available between 2002 and 2005. Temperature is modelled because time series are available since 2000. The transport model was set up with the following parameters: effective porosity of 0.22, aquifer bulk density of 1.820 g/cm3, aquifer heat capacity of cs = 800 J kg-1 K-1, water heat capacity of cw = 4184 J kg-1 K-1, and thermal diffusivity of 1.3 * 10-6 m2/s. Dispersivity is insensitive up to a length of 1 m and a larger dispersivity deteriorates the fit. In order to minimize mass balance error it is set to nil. Transport is simulated with MT3DMS (Zheng & Wang 1999) and the HMOC particle tracking scheme. 3.2.2.3 Results and Discussion Groundwater flow The comparison of measured and simulated hydrographs of the observation well TEG050 (as a representative example) shows the general behaviour of the hydraulic model. This observation well is located far enough from the well field, so that switching of wells and effects of local aquifer configuration are mitigated. The boundaries are far enough, thus, simulated heads are sensitive to the model parameterization. The variations of hydraulic head are induced by pumping regime of the waterworks Tegel, principially of well field West. Fig. 5: Measured and simulated piezometric heads (case 2 and 3) at observation well TEG050. 60 The fit of all four cases appears acceptable; in Figure 5 comparison of measured and simulated results are shown for the cases 2 and 3. Comparing the objective function for TEG050, case 3 is the best fit, the goodness of case 2 and 4 is similar, and case1 is the worst representation of the observed groundwater dynamics. The ratio of 1.6 between the largest and smallest value of the objective function is lowest for observation well 3301. Daily measurements are included into the model, which has a weekly time discretization. Thus, the model can only be optimized to a mean curve through the daily fluctuations. Though observation well 3301 contributes between 40% (case 1) and 70% (case 3) to the objective function, it shall be emphasized, that parameters only change slightly if it is taken out from the objective function. This is a strong indication that the parameterization is physically based (Hill 1998). Leakage The leakage coefficients are first approximatively calculated from in situ measurements, where the thickness of the clogging layer is assumed to be 10 cm (Wiese 2006). In Figure 6 measured and depth dependent leakage coefficients are depicted for the four cases to be studied. The depth dependency as well as the time variability of these coefficients is determined by inverse modelling. Fig. 6: Measured and modelled leakage of the lake bed. Each point represents the mean value at a certain observation location. Measurements of Hoffmann (2006) have been carried out between March 2004 and February 2005, measurements of this study in June and July 2004. Modelled values are adapted to the hydraulic situation in June/July 2004. In order to implement temporal variant leakage coefficients as well as easy communication with PEST, the MODFLOW2000 code has been modified. The resulting hydraulic heads are quite similar for both, case 2 and 3 (Fig. 5), though the parameterisation is quite different (Fig. 6). Under the premise of a linear temporal behaviour, the leakage is higher in greater depth. If the temporal behaviour is not forced to be linear, measurements indicate © IGB 2007 61 that the pattern is quite variable (Fig. 7) and the leakage is higher in shallow water (Fig. 6). A higher temporal resolution neither led to a considerably lower objective function nor resulted in a significantly different temporal behaviour. Fig. 7: Temporal leakage for case 2 and 3 (left axis); the pumping rate (right axis) is the monthly average of well field West. The leakage has revealed to be temporally variable. Potentiall, many mechanisms could cause the leakage to vary with time: Viscosity of water due to temperature effects, compression of lake bed by changing pressure head, clogging by suspended matter, chemical or bioclogging etc. Fig. 8: Measured and simulated piezometric heads at observation well TEG050 with case 4 parameterization. As show in Figure 7, for case 3 the leakage is correlated (R2=0.42) with the pumping rate and reacts with a small delay, but the observed hydraulic heads of the groundwater indicate an unsaturated zone for the shallower regions of Lake Tegel, which would cause the hydraulic independence of the 62 infiltration to the groundwater table. If the thickness of the clogging layer is small in comparison to the hydraulic head differences, high infiltration rates could occur because an increased hydraulic gradient across the clogging layer increases infiltration more than proportional. Using a simple, not physical based function of the leakage depending on the thickness of the unsaturated zone, the resulting distribution is shown in Figure 6 (turquoise line). The simulated hydraulic heads at observation well TEG050 are plotted in Figure 8. The application of case 4 instead of case 2 or case 3 improves the fit of observed and simulated hydraulic heads in general. The temporal dynamic coincides better, and also the arithmetic mean of hydraulic head in observation well 6053 between January 1998 and April 2002 of 28.84 m NN of case 4 is much closer to the observed mean of 28.81 m NN than case 3 with 29.23 m NN. The current parameterisation reproduces the most important temporal behaviour, and the reduction from 45 to 2 parameters is a significant improvement in parameter parsimony and solution uniqueness. Transport simulation The results of transport model are obtained using the hydraulic model of case 3 and transport parameters described above. Since the model is only calibrated using hydraulic data, the goodness of the presented transport behaviour indicate the correctness of the flow field (see Fig. 9). Temperature is only shown for well 13. Only for temperature the inland boundary values are well known thus results are very important for abstraction wells. As one example, the resulting travel times between the infiltration zone and observation wells 3301 and 3302 are approximately 4 month. Fig. 9: Selected results of transport modelling. 18O is shown for observation wells 3301, 3302, TEG371op, TEG371up, Well 12 and Well 13 for a period between 2002 and 2005. Temperature time series is presented for Well 13 for a perid between 2000 and 2005. © IGB 2007 63 Acknowledgement This study was carried out within the NASRI (Natural and Artificial Systems for Recharge and Infiltration) project of the KompetenzZentrum Wasser Berlin. The authors thank Berliner Wasser Betriebe and Veolia Water for the financial support of this study. References BEAR, J. (1972): Dynamics of fluids in porous media. Dover Publ., New York. DOHERTY, J. (2003): PEST – Model independent parameter estimation user manual, Watermark Numerical Computing, 336 pp. DOUSSAN, C., TOMA, A., PARIS, B., POITEVIN, G, LEDOUX, E., DETAY, M. (1993): Coupled use of thermal and hydaulic data characterize river-groundwater exchange. J. Hydrol., 153, 215-229. FRITZ, B., RINCK-PFEIFFER, S., NÜTZMANN, G., HEINZMANN, B. (2004): Conservation of water resources in Berlin, Germany, through different re-use of water. In: Steenvorden, J., Endreny, Th. (eds.): Wasrewater re-use and groundwater quality. IAHS publ. 285, 48-52. GRISCHEK, T., SCHOENHEINZ, D., WORCH, E., HISCOCK, K. (2003): Bank filtration in Europe – an overview. In: Dillon. P. (eds.): Management of aquifer recharge for sustainability. Balkema, Lisse, 485-488. HARBAUGH, A. W., BANTA, E. R., HILL, M. C., MCDONALD, M. G. (2000): MODFLOW-2000,The U. S. Geological Survey modular groundwater model. Open-file report 00-92. HILL, M. C. (1998): Methods and guidelines for effective model calibration. U.S. Geological Survey Water Resources Investigations Report 98-4005, Denver, CO. HOLZBECHER, E., ENGELMANN, B., NÜTZMANN, G. (2006): The viscosity effect on infiltrating surface water. Hydrogeol. J. (under review). HUETTEL, M., ROY, H., PRECHT, E., EHRENHAUSS, S. (2003): Hydrodynamical impact on biogeochemical processes in aquatic sediments. Hydrobiologia, 494, 231-236. LIN, C., GREENWALD, D., BANIN, A. (2003): Temperature dependence of infiltration rate during large-scale water recharge into soils. Soil Sci. Soc. Am. J., 67, 487-493. MIETTINEN, I., VARTIAINEN, T., MARTIKAINEN, P. J. (1997): Microbial growth and assimilable organic carbon in Finnish drinking waters. Water Science Technol. 35, 301-306. SCHUBERT, J. (2002): Hydraulic aspects of riverbank filtrtaion – field studies. J. Hydrol., 266, 145-161. WEBTECH360 (2003): Processing Modflow Pro – Users Manual, Fairbanks, USA, 413 pp. WIESE, B. (2006): Spatially and temporally scaled inverse hydraulic modelling, multitracer transport modelling and interaction with geochemical processes at a highly transient bank filtration site. PhD thesis, Geographical Institut, HumboldtUniversity of Berlin, 233 pp. ZHENG, C., WANG, P. P. (1999): MT3DMS – a modular three-dimensional multispecies model for simulation of advection, dispersion and chemical reactions of contaminants in groundwater systems, Documentation and User’s Guide, Rep. SERDP-99-1, Vicksburg, M.S. 64 G OLOSOV , S., K IRILLIN , G. 3.2.3 Modelling dissolved oxygen dynamics in icecovered shallow lakes Modellierung des dynamischen Sauerstoffverbrauchs in zugefrorenen Flachseen Key words: water quality, anaerobic zone, thermal regime, shallow lakes Abstract Based on the observational data from five freezing lakes located in Northwestern Russia and North America, the effect of the heat interaction between a water column and sediments on the formation, development, and duration of existence of anaerobic zones in ice-covered lakes is estimated. A simple one-dimensional model that describes the formation and development of the dissolved oxygen deficit in shallow ice-covered lakes is suggested. The model reproduces the main features of dissolved oxygen dynamics during the ice-covered period, that is, the vertical structure, the thickness and rate of an increase of the anaerobic zone in bottom layers. The model verification is performed against observational data. Results of verification show that the model adequately describes the dissolved oxygen dynamics in winter. The rates of DO consumption by bacterial plankton and by bottom sediments, depending on the heat transfer through the watersediment interface, are calculated. Received results allow predicting appearance of potentially dangerous anaerobic zones in shallow lakes and in separate lake areas in dependence on the thermal regime changes. Zusammenfassung Auf der Datengrundlage von fünf Seen aus dem Nordwesten Russlands und dem Norden Amerikas soll abgeschätzt werden, welche Rolle der Wärmeaustausch zwischen Wassersäule und Sediment bei der Bildung und der räumlichen und zeitlichen Entwicklung anaerober Zonen in eisbedeckten Flachseen spielt. Dafür wird ein einfaches 1-D-Modell vorgeschlagen, mit Hilfe dessen die Entstehung und der Verlauf eines Mangels an gelöstem Sauerstoff unter Eis beschrieben werden kann. Das Modell gibt die wesentlichen Merkmale des dynamischen Verhaltens von gelöstem Sauerstoff während der Eisbedeckung wieder, nämlich die Dicke der anaeroben Schicht, ihre vertikale Struktur und die Rate, mit der sie sich ausdehnt. Der Vergleich der Modellsimulationen mit den Messdaten zeigt, daß die Dynamik des gelösten Sauerstoffs im Winter vom Modell adequat widergespiegelt wird. Die vom Wärmeaustausch an der Wasser-SedimentGrenze abhängigen Raten, mit denen der gelöste Sauerstoff von bakteriellem Plankton und dem Sediment verbraucht wird, stellt das Modell ebenfalls bereit. Die erzielten Ergebnisse erlauben vorauszusagen, ob bei einem Wandel des thermischen Regimes in Flachseen (oder deren Teilen) potenziell gefährliche, anaerobe Zonen auftreten können. © IGB 2007 65 3.2.3.1 Introduction The water quality in freshwater reservoirs in many respects is determined by the content of dissolved oxygen (DO). In lakes with high DO concentration, the bacterial destruction of organic matter is accompanied by extraction of carbon dioxide, which is harmless for hydrocoles, into water. A decrease of the DO concentration or its complete absence leads to the activation of anaerobic processes, which usually occur with evolving such deoxidized gases as methane (CH4), hydrogen sulphide (H2S), and ammonia (NH3). Those are capable to not only worsen the water quality, but also to be toxic (especially it concerns H2S). The onset and continuous existence of the anaerobic zone in lakes leads to such negative consequences as fish kill, loss of benthic organisms, changes in the trophic chains of water ecosystems, etc. A DO deficit in shallow lakes occurs in absence of water aeration. The formation of anaerobic zones in lakes may take place during the open-water period and in winter. The duration of such phenomenon in the former case is rather short as occasional wind mixing of water column from top to bottom provides aeration of the bottom layers. The most dramatic situation may occur in ice-covered lakes located in moderate and high latitudes because the factors defining a DO regime in a shallow ice-covered lake essentially differ from those during the open-water period. First, it is related to main sources of oxygen flow. In winter, the ice cover excludes a gas exchange with atmosphere. Besides, amount of solar radiation penetrating into water becomes negligible that leads to a drastic decrease of photosynthetic intensity. Thus, main sources of oxygen supply practically disappear, and only consumption of oxygen by bacterial plankton in the process of organic matter decomposition together with its absorption by bottom sediments control the DO content in a lake (Hargrave 1972). The rate of DO consumption in ice-covered lakes as a rule depends on a set of biological and hydrophysical factors. Usually, the biochemical factors, such as vital functions of the different organisms (including bacterial plankton) within the benthic community, the concentration of the organic matter and DO in the near-bottom layers, are considered as the main parameters responsible for the formation of the oxygen depletion in icecovered lakes (Hutchinson 1957; Hargrave 1972; Mathias and Barica 1980; Cornett and Rigler 1987). On the other hand, it is well known that the life activity of the bacterial plankton, which is the main consumer of DO, is strongly dependent on the water temperature (Boylen and Brock 1973; Welch et al. 1976; Charlton 1980; Kovaleva et al. 2003). In spite of this fact, it is commonly assumed that as long as the temperature in ice-covered lakes is low and varies in a very narrow range (from 0 to 4-5°C), its effect on the bacterial activity is not great and DO winter depletion depends only on the concentration of organic matter in water column. Nevertheless, in the frames of the present study the efforts to evaluate the role of the temperature in the development of DO winter depletion in ice-covered lakes were undertaken. As it will be shown below, in some cases 66 the so-called “effect of under-ice warming” can lead to considerable strengthening in the development of anoxic conditions in ice-covered lakes. 3.2.3.2 Material and Methods Field data collected in three Russian, one American, and one Canadian freezing lake were taken as the empirical material to perform the study. Russian and American lakes are natural water-bodies of different trophic state. Russian lakes Chainoe, Krasnoe, and Vendyurskoe are classified as mesotrophic. American Lake Alequash belongs to the eutrophic type whereas Canadian Lake Midnapore is an artificial urban water body of mesotrophic type located in Calgary (for details see Golosov et al. 2007). The phenomenon of winter DO depletion is intrinsic to Lake Allequash in the same way as for the Russian lakes (often to the point of full DO disappearance). In Lake Midnapore appearance of DO depletion is irregular and there were detected no cases of full DO consumption (Meding 2000). All data from Russian, American and Canadian lakes represents the DO and water temperature vertical distributions from top to bottom of the water column, measured in different dates from the beginning to the end of icecovered periods. Except Lake Midnapore, the thermal regime of the lakes in consideration is similar, including the under-ice warming of the water column due to heat flux from the sediments. The near bottom temperature varies from 0.5-1.0°C in the beginning of the ice-covered period to 4-5°C in the end. The data from Russian lakes and Lake Alequash were used to derive parameterizations of the model. These data were analyzed and processed in terms of the time dependent relations between the values of the DO deficit and temperature. Obtained functional relations were used to estimate the rates of the total DO consumption in lakes in dependence on the water temperature. The model verification was performed against the most detailed data from Lake Vendyurskoe and data from Lake Midnapore as the independent lake. Finally, the derived results were used in numerical experiments on studying the formation and development of the anoxic conditions in Lake Vendyurskoe. 3.2.3.3 Empirical verification of the model parameterisations The model considers the DO vertical distribution within a ‘water-sediment’ system for the three most common cases (see Fig.1 a, b, c), that are: 1) the anoxic zone in a bottom water layer is absent and oxidizing conditions in the upper layer of bottom sediments prevail; 2) the DO concentration in the bottom layer is close to zero, the oxidized layer in bottom sediments is absent; and 3) the DO in the near-bottom layer is absent, and the anoxic zone starts to develop from bottom towards top of the water column. It is evidently from the field data, that the temporal variability of DO concentration in the vicinity of ice is lower than that in bottom layers for one order of magnitude at least. Therefore, in the frames of the model the DO © IGB 2007 67 Fig. 1 Evolution of the DO vertical profile in an ice-covered lake during the winter (see text for further explanation). concentration at water-ice boundary can be assumed as constant during the ice period. A detailed model description of the formation and development of DO depletion in shallow ice-covered lakes, which uses in analogy to thermal regime modeling (Mironov et al. 1991; Kirillin 2003; Golosov et al. 2003) the socalled self-similarity approach can be found in Golosov et al. (2005). In the framework of this approach, invariability of the shapes of the vertical DO profiles in a water column and the upper layer of sediments is assumed. 68 The Results of verification of the model are mentioned here only briefly. A detailed presentation was given in (Golosov et al. 2007). Measured and calculated vertical DO profiles of Lake Vendyurskoe corresponding to different dates of the winter 2001-02 were compared for the water column (Fig. 2a. in Golosov et al. 2007) and for the upper oxidized layer of the sediments (Fig. 2b in Golosov et al. 2007). Because the authors do not possess own observational data on the vertical distribution of DO in sediments (which can be received only with use of special micro-profilers) data of natural and laboratory studies performed by other investigators (Archer and Devol 1992; Jorgensson and Revsbech 1985; Lorke et al. 2003) were used in the sediment comparison. Results of calculations show that the model describes the temporal variability of the vertical DO profiles, from the ice cover formation to the end of its existence, fairly well. This means that the representation of the water DO profile assumed in the model, is quite realistic. 3.2.3.4 Results of the model runs and Discussion The verification of the model was performed against the field data collected in two lakes, namely Lake Vendyurskoe (Russia) and Lake Midnapore (Canada). Lake Midnapore was chosen for the model verification as independent object since data from this lake were not used in deriving the model parameterizations. Among aforementioned field data from different lakes the most detailed data were obtained in Lake Vendyurskoe in 2001-02. That was the main reason to choose Lake Vendyurskoe for studying the peculiarities of the winter DO depletion. As the first step of the model verification, the temporal dynamics of DO concentration in Lake Vendyurskoe was calculated. To reveal the peculiarities of the phenomenon under study, two locations with different depths were chosen, namely St. 9 and St. 16 of 11.5 m and 5 m depth, respectively. The differences between the stations consist not only in the depths and places of location, but mainly in the thermal regime during the ice-covered period Thus, the near-bottom temperature at St. 16 varies from 0.9°C in the middle of November (beginning of ice formation) to 2.5°C in the middle of April. The corresponding variability of temperature at St. 9 covers the range from 1.2°C to 4.6°C. The effect of the temperature on the formation of DO depletion was studied under different conditions. Firstly, we calculated the DO deficit and the thickness of the anoxic zone using the real temperature conditions observed during the surveys. Results of these runs are presented in Fig. 2 a, b, c. The distance between both stations does not exceed one kilometer, but the oxygen conditions differ strikingly. The storage of DO in bottom layers at the deeper station became negligible no longer than in a half of month after the ice formation (see Fig. 2a,b), whereas at St. 16 the more or less essential deficit of DO appeared just in the middle of April (see Fig. 2c). At St. 9, the completely anoxic zone started developing after full DO consumption and reached the thickness of 1.5 m in the end of the winter. © IGB 2007 69 Fig. 2: Evolution of the DO concentration and of the anoxic zone thickness H in Lake Vendyurskoe (a, b, c) and in Lake Midnapore (d). Diamonds and squares are the DO concentrations measured under the ice cover and in the near-bottom water correspondingly. Triangles mark the measured thickness of the anoxic zone. Dashed and solid lines correspond to the model DO concentrations under the ice and in the near-bottom water. 70 At the St. 16, the anoxic zone did not appear at all. The values of the rate of DO consumption for the under ice and near bottom zones were the same for the both stations. Thus, the model runs differ from each other only by the courses of temperature. In other words, the difference in peculiarities of thermal regime between two stations can be responsible for the features of formation of DO depletion within lake. In addition to the good agreement between measured and calculated near bottom DO concentration (Fig. 2a, c), it should be noted that the variability of DO concentration in the vicinity of ice actually is very small, e.g. the corresponding assumption accepted at the model formulation is correct. The next set of the model runs was intended to reproduce the winter course of DO concentration in Canadian Lake Midnapore. Before discussion of the results of simulations, it is essential to note, that the thermal regime of the lake considerably differs from that of the other lakes. The effect of under-ice warming is not pronounced in this lake. The near bottom temperature is almost constant during the whole winter and remains close to the value of temperature of water maximal density, e.g. 4C. It means that the limiting effect of the low water temperature on the rate of formation of DO depletion in this case should be less than that in the case of Lake Vendyurskoe. Results of the model application to Lake Midnapore presented in Fig. 2d confirm that statement. A decrease of the DO concentration in the nearbottom area takes place at essentially higher rate than that at St. 16 in Lake Vendyurskoe though both sites are of the same depth. As a result, the DO concentration in Lake Midnapore reaches its minimal values in 90 days after the ice-covered period started, whereas in Lake Vendyurskoe the same values of DO concentration were observed in 150 days (Fig. 2c). The following runs of the model were intended to reveal the effect of the shift of thermal regime on the formation of DO depletion. The under-ice DO regime for St. 9 was calculated using the temperature measured at the “cold” St. 16, and vice versa, the “warm” winter conditions for St. 16 were simulated with temperature data obtained at the St. 9. Results of simulations are presented in Fig. 3. The model experiments show a rather strong dependence between the DO and thermal regimes of lakes (or their single areas). Under conditions of “cold” winter, the full consumption of DO at deep St. 9 has been developed in two months after the ice period began. Respectively, the anoxic zone started to develop later comparing to the “warm” case and reached essentially lower thickness in the end of winter. These results were quite expected. A more dramatic situation was revealed by simulations for shallow St. 16. The shift in temperature entailed serious worsening in the DO regime. The fully anoxic zone is observed already in 40 days after the ice formation. The rate of its development reached 0.5 cm d-1. It is not as high as at St. 9, but notice that in the case of “cold” winter there was no anoxic zone at this station at all. © IGB 2007 71 Fig. 3: Results of numerical experiments: a, b – evolution of the near bottom DO concentration and the thickness of the anaerobic zone at St. 9 in case of “cold” winter; c, d – the same at the St. 16 in case of “warm” winter. The results of numerical experiments performed in the present study allow formulating some conclusions on the nature and the reasons of the winter DO depletion in shallow ice-covered lakes. In lakes, where the concentration of the organic matter is not a limiting factor (the cases of mesotrophic and eutrophic lakes), the winter deficit can be formed due to peculiarities of the lake winter thermal regime. In turn, the latter is affected by warming/cooling conditions during the previous summer/autumn and by the heat interaction between a water column and sediments. So, it means that 72 the winter DO depletion in many respects depends not only on the biochemical processes in lakes and duration of the ice-covered period, but can be determined by the physical factors acting long before the ice formation in a lake. Actually, as soon as the thermal regime of ice-covered lake plays an important role in formation of DO winter depletion, all factors affecting the heat storage of sediments, can straightly or indirectly influence on the rate of formation and duration of anoxic conditions in a lake. First of all, it concerns to the summer mixing conditions and duration of “autumnwinter” cooling of a lake. The heat accumulation by sediments under neutral or weak density stratification is much more efficient compared to the conditions of stably stratified water column. In summer, frequent turbulent mixing of the water column from top to bottom provides the effective heat penetration from warm upper layers down to the near-bottom zone. As a result, sediments accumulate a considerable amount of heat. And vice versa, the existence of the stable density stratification in a water column prevents the downward heat penetration. The heat exchange between near-bottom water and sediments is depressed in this case, and the heat content of sediments is small. The duration of the “autumn-winter” cooling, following after summer warming, also influences on the sediments heat content in the beginning of ice-covered period. In a case of fleeting and very intensive water column cooling in autumn, sediments retain considerable heat content to the time of ice formation. That leads to the rapid under-ice water warming after the freeze-up and, as a consequence, to the rapid formation of DO depletion. On the contrary, in a case of long “autumn-winter” cooling, sediments get cold enough and its heat content is too small to provide a reasonable increase of water temperature during the winter. In this case the sediments are not able to increase the near-bottom temperature considerably, and the low water temperature can prevent the fast development of the DO depletion. Some logical deduction can be done concerning the effect of the expected global warming on the DO regime of ice-covered lakes. Taking into account the aforementioned results of the model runs, the warming may play an essentially negative role in the deterioration of the DO regime in freezing lakes. The expected increase in winter near-bottom temperature can lead to a more frequent formation of the anoxic zones in lakes. Moreover, one can expect that the time and spatial scales of those events would increase considerably. Acknowledgement The present study is supported by European Commission (project INTAS 01-2132), the Swedish Institute (VISBY Programme), Ǻke och Greta Lisshed Foundation, Sweden, the Russian Academy of Sciences, and the German Foundation of the Basic Research (DFG, Project KI-853/3-1 in frames of the program „AQUASHIFT“). The support is gratefully acknowledged. Authors express their admiration and gratitude to the field research team of the Northern Water Problems Institute for their heroic efforts at collecting field data during winter field campaigns. © IGB 2007 73 References ARCHER D, DEVOL A. 1992. Benthic oxygen fluxes on the Washington shelf and slope: A comparison of in situ microelectrode and chamber flux measurements. Limnol. Oceanogr. 37: 614-629. BOYLEN C, BROCK, T. 1973. Bacterial decomposition processes in Lake Wingra sediments during winter. Limnol. Oceanog. 18(4): 628-634. CHARLTON M. 1980. Hypolimnion oxygen consumption in lakes: discussion of productivity and morphometry effects. Can. J. Fish. Aquat. Sci. 37: 1531-1539. CORNETT R , RIGLER F. 1987. Vertical transport of oxygen into the hypolimnion of lakes. Can. J. Fish. Aquat. Sci. 44: 852-858. GOLOSOV S, ZVEREV I, TERZHEVIK A. 2003. Thermal Structure and Heat Exchange in Ice-Water Column-Sediment System. In: TERZHEVIK, A.(ED) Proc. 7th Int. Symp. Physical Processes in Natural Waters, July 2003, Petrozavodsk, Russia: 17 28 GOLOSOV S, SHIPUNOVA E, MAHER OA, TERZHEVIK A, ZDOROVENNOVA G. 2005. Physical background of oxygen depletion development in ice-covered lakes. In: FOLKARD A, JONES I (EDS). Proc 9th Europ Workshop on Physical Processes in Natural Waters, September 2005, Lancaster University, UK, 229–237. GOLOSOV S, MAHER OA., SCHIPUNOVA E, TERZHEVIK A., ZDOROVENNOVA G, KIRILLIN G.2007. Physical background of the development of oxygen depletion in ice-covered lakes. Oecologia, 151: 331-340 HARGRAVE B. 1972. A comparison of sediment oxygen uptake, hypolimnetic oxygen deficit and primary production in Lake Esrom, DK. Verh. Int. Ver. Limnol. 18: 134-139. HUTCHINSON G. 1957. A treatise on limnology. Vol I. J.Wiley & Son, NY, 1015 p. JORGENSEN B, REVSBECH N. 1985. Diffusive boundary layers and the oxygen uptake of sediments and detritus. Limnol. Oceanogr. 30: 111-122. KIRILLIN G. 2003. Modeling of the Shallow Lake Response to Climate Variability In: TERZHEVIK, A (ED). Proc. 7th Int. Symp. Physical Processes in Natural Waters, July 2003, Petrozavodsk, Russia: 144-148. KOVALEVA N, MEDIENTZ V, GAZETOV E. 2003. Influence of temperature and oxygen content on the intensity of the organic matter decay in Black Sea. Gidrobiologicheskiy Zhurnal (J. of Hydrobiology) 39(4): 34-40. (in Russian) LORKE A, MULLER B, MAERKI M, WUEST A. 2003. Breathing sediments: The control of diffusive transport across the sediment-water interface by periodic boundarylayer turbulence. Limnol. Oceanogr. 48(6): 2077-2085. MATHIAS J, BARICA J. 1980. Factors controlling oxygen depletion in ice-covered lakes. Can. J. Fish. Aquat. Sci. 37: 185-194. MEDING M. 2000. Structure and function in shallow prairie lakes: macrophytes and winter anoxia. Master thesis, University of Calgary: 124 p MIRONOV D, GOLOSOV S, ZILITINKEVICH S, KREIMAN K, TERZHEVIK A. 1991. Seasonal changes of temperature and mixing conditions in a lake. In: ZILITINKEVICH S (ED). Modelling Air-Lake Interaction. Physical Background. Springer: 74-90. WELCH H, DILLON P, SREEDHARAN A. 1976. Factors affecting winter respiration in Ontario lakes. J. Fish. Res. Board Can. 33: 1809-1815. 74 3.3 Research Topic 3 Forschungsschwerpunkt 3 Adaptation, plasticity and dynamics of communities Adaptation, Plastizität und Dynamik von Biozönosen © IGB 2007 75 76 G LOESS , S., H UPFER , M., R ATERING , S., G ROSSART , H.-P. 3.3.1 Detection and phylogenetic characterization of polyphosphate accumulating bacteria in lake sediments Nachweis und phylogenetische Charakterisierung von Polyphosphatakkumulierenden Bakterien in Seesedimenten Key words: polyphosphate, sediment, bacteria, polyphosphate accumulating bacteria (PAO), single cell separation, laser microdissection, DGGE Abstract The direct contribution of microorganisms to the mobilization and immobilization of phosphorus (P) in aquatic sediments has been controversially discussed since more than one decade. Polyphosphate (PolyP) storage is an universal ability of many microorganisms and has been technically optimized in wastewater treatment plants (WWTP) by providing conditions for an enhanced biological phosphorus removal (EBPR). Poly-P accumulating organisms (PAO) in sediments, thus, might be of high ecological importance. PAO in sediments are able to insert P into the benthic food chain and affect the permanent P mineral deposition by physiologically inducing rapid P release. Although several studies indicate that Poly-P substantially contributes to total P in the uppermost sediment layer, its origin as well as the microorganisms and mechanisms involved in Poly-P storage and cycling are unknown. Therefore, we have screened sediments from eight lakes different in trophy and limnological features for the presence of PAO. We have used denaturing gradient gel electrophoresis (DGGE) with a set of primers specific for bacteria closely related to the genus Rhodocyclus, belonging to the most popular PAOs in WWTP with EBPR. Our screening shows that members of the genus Rhodocyclus are present in all studied sediments. However, subsequent quantification of these PAO by fluorescence in situ hybridization (CARD-FISH) with oligonucleotide probes specific for the Rhodocyclus-PAO revealed that they only contribute to <1% of total DAPI counts. Therefore, we have established a single cell approach for the detection and phylogenetic characterization of hitherto unknown PAO in freshwater sediments. Sediment bacteria of Lake Stechlin where highest amounts of Poly-P have been quantified by 31P Nuclear Magnetic Resonance Spectroscopy were stained with DAPI for localization of PAO. Poly-P positive cells were subsequently collected by laser microdissection and could be analyzed with molecular methods for their phylogenetic characterization. Our preliminary results show that the presented method can be successfully used to collect and identify single bacteria with a specific physiological attribute, such as Poly-P storage. Zusammenfassung Seit mehr als einem Jahrzehnt wird in der Literatur sehr kontrovers diskutiert, in welchem Maße Mikroorganismen direkt an der Freisetzung und © IGB 2007 77 Festlegung von Phosphor (P) in Sedimenten beteiligt sind. Polyphosphat (Poly-P) Speicherung ist eine universelle Eigenschaft von vielen Mikroorganismen und wurde in Kläranlagen (wastewater treatment plants, WWTP) durch das Einstellen von Bedingungen, die eine erhöhte biologische P Entfernung (enhanced biological phosphorus removal, EBPR) ermöglichen, technisch optimiert. Poly-P akkumulierende Organismen (PAO) in Sedimenten sind daher von besonderer ökologischer Wichtigkeit. PAO in Sedimenten können P in die benthische Nahrungskette einschleussen und beeinflussen die mineralische P Deposition durch ein schnelles, physiologisch induziertes Freisetzen von P. Obwohl verschiedenste Studien zeigen, dass Poly-P substantiell zum gesamten P Pool in der obersten Sedimentschicht beiträgt, sind sowohl der Ursprung als auch die an der Speicherung und am Umsatz von Poly-P beteiligten Mikroorganismen und Mechanismen weitestgehend unbekannt. Daher haben wir Sedimente von acht verschiedenen Seen unterschiedlicher Trophie und limnologischer Eigenschaften auf die Anwesenheit von PAO mittels denaturierender Gradienten-Gelelectrophore (DGGE) und Rhodocyclusspezifischen Primern überprüft. Die Gattung Rhodocyclus stellt eine der häufigsten PAO in WWTP mit EBPR dar. Unsere Ergebnisse zeigen, dass Vertreter der Gattung Rhodocyclus in allen untersuchten Sedimenten anwesend sind. Allerdings zeigte die anschliessende Quantifizierung dieser PAO mit Rhodocyclus-spezifischer Fluoreszenz in situ Hybridisierung (CARD-FISH), dass ihr Anteil bei <1% der gesamten Bakterienzahl liegt. Daher haben wir einen Einzelzellansatz für die Detektion und phylogenetische Charakterisierung von bisher unbekannten PAO in limnischen Sedimenten entwickelt. PAO aus dem Sediment des Stechlinsees, in dem die höchsten Poly-P Konzentrationen mittels 31P Nuclear Magnetic Resonance Spectroscopy (NMR) bestimmt wurden, wurden zur Lokalisierung mit DAPI gefärbt. Poly-P positive Zellen wurden anschliessend mit der LaserMikrodissektion gesammelt, um sie mit molekular-biologischen Methoden phylogenetisch zu charakterisieren. Unsere vorläufigen Ergebnisse zeigen, dass die vorgestellte Methode erfolgreich eingesetzt werden kann, um einzelne Bakterienzellen mit bestimmten physiologischen Eigenschaften, z.B. der Poly-P Speicherung, zu sammeln und phylogenetisch zu charakterisieren. 3.3.1.1 Introduction Many studies show that microbial activity in surface sediments affects the release of P from sediments into the water by various mechanisms (e.g. Boström et al. 1988, Gächter & Müller 2003); i.a. hydrolysis of dissolved Poly-P is fast in pore water of sediments (Hupfer et al. 1995). Several microorganisms in aquatic ecosystems are able to excessively and rapidly take up P beyond their physiological need ("luxury uptake"). Synthesis and storage of Poly-P are common among microorganisms (especially for cyanobacteria, McDignum et al. 2005) when P is sufficiently available after phases of acute P starvation (“overplus uptake”). The increased stress due to limited P availability implies the synthesis of a high-affinity uptake system for 78 orthophosphate and additional enzymes which transform orthophosphate into insoluble Poly-P inside the cell. These adaptations are valuable advantages for competition with other organisms such as phytoplankton when inorganic nutrients become limiting (e.g. Eixler et al. 2006). Furthermore, laboratory experiments have demonstrated that Poly-P storage in microalgae and cyanobacteria is influenced by various other environmental conditions, e.g. light (Sianoudis et al. 1986), sulphur (Lawerence et al. 1998), and nitrogen availability (Küsel et al. 1989). While it is well accepted that microorganisms living in activated sludge are able to store high amounts of P inside the cell in form of Poly-P (e.g. up to 10 % of total dry mass in a pure culture of Acinetobacter 210A, Deinema et al. 1985), the presence and influence of such heterotrophic bacteria in lake sediments for P turnover is still unclear. Phosphorus in the biomass of sediment microorganisms as a regulator for the dynamics of benthic P fluxes has been controversially discussed throughout the last two decades. Experimental data (Gächter et al. 1988, Waara et al. 1993), theoretical considerations (Davelaar 1993, Gächter & Meyer 1993), and detection of Poly-P in limnetic sediments (Hupfer et al. 2004, Reitzel et al. 2006) give strong indications that sediment microorganisms are indeed directly involved in P fixation. Other authors, however, doubt or ignore the relevance of microbial biomass as an important link for P cycling in sediments (Golterman 2004). Most of our present knowledge on Poly-P accumulating bacteria is based on studies in activated sludge showing an enhanced biological P removal. For optimization of sewage treatment processes a fundamental understanding of the bacterial sludge communities and their dynamics is necessary. Several types of bacteria isolated from activated sludge are able to take up P excessively and accumulate it intracellular in form of Poly-P, e.g. species of the genus Acinetobacter (Fuhs and Chen 1975), Microlunatus phosphovorus (Nakamura et al. 1995), members of the genus Tetrasphaera (Maszenan et al. 2000) or Lampropedia spp. (Stante et al. 1997). Culture independent methods (e.g. DGGE, clone libraries, and FISH with specific oligonucleotide probes) showed that members of the Betaproteobacteria closely related to the genus Rhodocyclus (e.g. Bond et al. 1995, Hesselmann et al. 1999, Kong et al. 2004), Alphaproteobacteria (e.g. Kawaharasaki et al. 1999) and Tetrasphaera related Actinobacteria (e.g. Bond et al. 1999, Kong et al. 2005) could be detected in large numbers in activated sludge. Using these techniques, it has been also shown that members of the genus Acinetobacter contribute to a minor fraction of the sludge community (e.g. Wagner et al. 1994). All bacterial classes potentially involved in Poly-P storage were detected in lake sediments as well (Uhlmann et al. 1998, Wobus et al. 2003). This notion is not surprising, since some lake sediments could be considered as “natural activated sludge” (Höll 1930). Hence, it can be assumed that PAO are also responsible for the presence of Poly-P in lake sediments (Davelaar 1993). Until now the origin as well as the microorganisms and mechanisms involved in Poly-P storage and cycling in lake sediments are hardly known. © IGB 2007 79 Therefore, we have screened sediments from eight lakes different in trophy and limnological features for the presence of PAO by using denaturing gradient gel electrophoresis (DGGE) with a set of primers specific for Candidatus “Accumulibacter phosphatis” a member of the family Rhodocyclaceae and one of the most popular PAO (Crocetti et al. 2000; Kong et al. 2004). Although these PAO were present in all studied lakes, their quantification by CARD-FISH revealed that they contributed <1% to the total bacterial number. Therefore, we aimed to establish a method by which single cells of PAO from lake sediments can be identified and at the same time separated for subsequent precise phylogenetic identification. Our previous results show that single cells with a specific physiological attribute, such as Poly-P storage, can be collected by laser microdissection for subsequent analysis with molecular methods for precise phylogenetic characterization. 3.3.1.2 Material and Methods Sampling and sample preparation For screening of the presence of already known PAO sediments from the following lakes have been taken: Lake Stechlin (between June 2004 and May 2006), Lake Scharmützel (between June 2004 and April 2005), Lake Arend (June 2004, October 2004, May 2005), Lake Grosse Fuchskuhle (South-East and North-West Bassin), Lake Groß Glienicke, Lake Auen, Lake Petersdorf, and Lake Müggel (each in June 2004). For identification and separation of single PAO by laser microdissection sediment samples were taken from Lake Stechlin in June 2006 at the deepest point of the lake (69.5 m). Lake Stechlin is oligotrophic and characterized by an all-seasonal high hypolimnetic oxygen concentration near the bottom (> 60% O2 saturation). Sediment cores were collected using a sediment sampler (Uwitech, Mondsee, Austria). The uppermost biofilm-like sediment (up to 5 mm) was immediately siphoned using a 50 ml plastic syringe equipped with a flexible tube. To obtain a representative composite sample four to seven replicate cores per site were pooled. The samples were brought into the lab in a dark cool box and immediately processed for further analyses. For the detection of potential Poly-P storing bacteria cells were extracted from the sediment with sodiumpyrophosphate (0.1 %, w/v), gentle sonicated and shaked over head for 30 min. After an additional 30 min sedimentation step the supernatant was removed, sonicated again and the extracts were fixed 1:1 with ethanol (99 %, v/v). For DAPI (4`, 6- Diaminido-2-phenylindole dehydrochloride)-staining the fixed extracts were filtered onto 0.2 µm polycarbonate membranes (Nucleopore®, Whatman, Germany) and incubated with DAPI (20 µg ml-1) for 15 min. When used at high concentrations DAPI stains Poly-P granula with an intensive yellow fluorescence (Streichan et al. 1990). The laser microdissection was performed during the next 48 hours after DAPI staining. For counting the DAPI positive cells a Leica DR-MB epifluorescence microscope with 1000x magnification was used. 80 Polyphosphate measurements The extraction of Poly-P from sediments was done according to a standard protocol by pre-extraction with edatic acid (EDTA) followed by an alkaline extraction procedure (NaOH-EDTA) (Hupfer et al. 1995, 2004). 31P-NMR analyses were carried out on a Bruker 102 DRX 600 spectrometer. The identification and quantification of peaks are described in Hupfer et al. (1995). DNA extraction About 500 mg sediment was charged with sodium phosphate buffer (120 mM), SDS (25%) and zirconia beads and vortexed in a horizontal vortexer followed by the enzymatic cell lysis with proteinase K and lysozyme. Proteins were precipitated using ammoniumacetate (7.5 M). After removing the proteins through a centrifugation step, the DNA was precipitated using ispropanol. The pellet was washed twice with 70 % (v/v) ethanol. The DNA was loaded onto an agarose gel (1.5 %) to check their quality. PCR and DGGE For DGGE genomic DNA was amplified using the following PCR reaction mixture: 2 µl DNA, bovine serum albumin (final conc. 0.125 µg), 250 nM of each primer (MWG biotech AG, Ebersberg), 200 µM of each dNTP, 2 mM MgCl2, 10 µl 10x PCR buffer, 0.5 u RedTaq DNA Polymerase (Bioline GmbH, Luckenwalde). The final volume of 50 µl was adjusted with ultrapure water. For PCR amplification a Gradient Cycler PT200 (MJ Research) was used with an initial denaturation step at 95°C for 3 min, followed by 30 cycles of denaturation at 95°C for 1 min , annealing at 60°C for 1 min, and extension at 72°C for 3 min. A final extension step was carried out at 72°C and 15 min, cooling at 4°C completed the reaction. The following primer set has been used: 341f-gc (5’ – CGC CCG CCG CGC CCC GCG CCC GTC CCG CCG CCC CCG CCC GCC TAC GGG AGG CAG CAG – 3’, Muyzer et al. 1993) and PAO846 (5'- GTT AGC TAC GGC ACT AAA AGG -3', Crocetti et al. 2000). DGGE was performed using the INGENYphorU System (Ingeny International, Netherlands). PCR products were loaded onto a polyacrylamide gel in 1xTAE buffer (20 mM Tris, 10 mM acetate, 0.5 mM EDTA, pH 7.6). The gel consisted of a formamide/urea gradient ranging from 40 to 70%. Gel electrophoresis was performed for 20 hours and 100 V at 60°C. Staining of the gel was carried out with 1x SYBR Gold (Molecular Probes, Invitrogen, Germany) for 35 min followed by a 10 min destaining step with demineralized water. The stained gel was immediately photographed on a UV transillumination (BioRad, Germany). CARD-FISH Fluorescence in situ hybridization with horseradish peroxidase (HRP)labelled probes and tyramide signal amplification was modified performed according to the protocol of Pernthaler et al. (2002). In brief, ethanol-fixed sediment extracts were brought onto coated slides, embedded, and permeabilized. Whole-cell in situ hybridizations on the slides were done with © IGB 2007 81 5`-HRP-labelled oligonucleotide probes EUB338 I to III (Bacteria including Verrumicrobia and Planctomycetes, Daims et al. 1999), PAO462+PAO846 (Crocetti et al. 2000) and with a formamide concentration of 55% in the hybridization buffer. The oligonucleotide probes were purchased from ThermoHybaid (Ulm, Germany). The slides were inspected with a Leica DRMB epifluorescence microscope at 1000x magnification. Non Contact Laser Microdissection Laser microdissection and pressure catapulting (LMPC) were performed with the PALM MicroBeam system in combination with the PALM RoboMover controlled by the PALM RoboSoftware v2.2 (P.A.L.M. Microlaser Technologies GmbH, Bernried, Germany). The MicroBeam system consisted of an Axiovert 200 M microscope (Carl Zeiss MicroImaging GmbH, Germany) equipped with a 100 W mercury lamp. The Nuclepore filters were inspected with the fluorescence filter FS18 (P.A.L.M. Microlaser Technologies GmbH, Bernried, Germany) at 400x magnification. Bacterial cells with bright yellow illuminating inclusions were laser dissected out of the filter. The excised cells were catapulted into the lid of an AdhesiveCap (P.A.L.M. Microlaser Technologies GmbH, Bernried, Germany). DNA Extraction and PCR of excised cells Lysis of the cells was done “upside down” in the cap for 2 minutes in liquid nitrogen and subsequently 2 minutes at 96°C, each three times. The cells were vortexed and centrifuged to the bottom of the cap. The 16S rRNA genes were targeted for amplification by direct PCR using a DNase I digested mastermix containing the universal bacterial primer pair 341f (5’ – CCT ACG GGA GGC AGC AG – 3’) and 907r (5’ – CCG TCA ATT CMT TTG AGT TT – 3’) (Muyzer et al. 1993) (each 250 nM), bovine serum albumin (final conc. 0.5 µg; Roth, Karlsruhe, Germany), 200 µM of each dNTP (Bioline GmbH, Luckenwalde, Germany), 2 mM MgCl2, 10x PCR buffer, 0.2 U HotStarTaq DNA Polymerase (Qiagen, Hilden, Germany) in.a final volume of 22 µl. For PCR amplification a Gradient Cycler PT200 (MJ Research) was used with an initial denaturation step at 95°C for 2 min, followed by 49 cycles of denaturation at 95°C for 1 min, annealing at 55°C for 40 sec, and extension at 72°C for 1:30 min. A final extension step was carried out at 72°C for 10 min; cooling at 4°C completed the reaction. 3.3.1.3 Results and discussion Evidence for Poly-P Poly-P was found in surficial sediment samples of oligotrophic Lake Stechlin and accounted for ca. 20 % of total P (Figure 1). Such high values have never been published before and, thus, provided a good basis for searching and identifying Poly-P storing bacteria in lake sediments. Detection of PAO in lake sediments We have used the primer pair 341f-gc and PAO846 for DGGE analysis. Originally primer PAO846 has been used as an oligonucleotide probe 82 specific for members of the Rhodocyclaceae (Crocetti et al. 2000). Rhodocyclus related sequences were detected by DGGE in all samples (Figure 2) indicating that this cluster is widely distributed in freshwater sediments. Fig. 1: 31 P-NMR spectrum of the surficial lake sediment of Lake Stechlin (NaOH-extract), 17.06.2004, 68 m Fig. 2: DGGE-analysis of samples from lakes Stechlin, Scharmützel, Arend, Grosse Fuchskuhle (Northeast and Southwest basin), Gross Glienicker, Auen, Petersdorf, Müggel and activated Sludge (Wassmannsdorf). St = lab internal DGGE standard. The application of the CARD-FISH protocol with oligonucleotide probes PAO462 and PAO846 revealed that the popular PAO members of the Rhodocyclaceae (Figure 3) contributed to <1% of the total bacterial community suggesting that they play a minor role for Poly-P storage in a variety of freshwater sediments. This is in obvious contrast to results of Crocetti et al. (2000) who found that in a laboratory-scale plant with enhanced biological P removal a positive correlation between percent P in the sludge and numbers of PAO probebinding cells occur. Since the percentage of PAO462/PAO846 positive cells was low in all samples studied we assume that in natural sediment samples (e.g. Lake Stechlin with high © IGB 2007 83 concentrations of Poly-P) other bacteria must be important for Poly-P storage. Therefore, we have developed a method to simultaneously identify and separate single cells of PAO fur further molecular characterization. Figure 3: Poly-P storing bacterium of the genus Rhodocyclus detected by CARDFISH using probes PAO462 and 846 (as indicated by the white arrow). Separation of Poly-P accumulating bacteria by Laser Microdissection Poly-P accumulating bacteria from lake sediments were identified by DAPI staining of intracellular Poly-P granules. DAPI can serve as standard stain for visualization of Poly-P since at high concentrations DAPI also stains Poly-P granula with an intensive yellow fluorescence (Figure 4, Streichan et al. 1990). DAPI staining is not exclusively specific for Poly-P, however, DAPI staining of other polymers results in a weak and fast fading yellow fluorescence (Streichan et al. 1990). Therefore we are confident that in our study cells with bright yellow fluorescence were PAO. From Lake Stechlin sediment sample (June 2006), ca. 100 Poly-P containing cells were cut out and catapulted into a sterile cap using the PALM MicroBeam technology (P.A.L.M. Microlaser Technologies GmbH, Bernried, Germany). 10 µm Lake Stechlin Activated sludge Fig. 4: Detection of Poly-P storing bacteria by DAPI staining Previously the PALM laser technology has been successfully used in analyzing eukaryotic material for a variety of scientific applications, e.g. forensic, botany, pathology or neurosciences. Even, potentially pathogenic bacteria from histological tissue have been detected with fluorescently labelled oligonucleotide probes, microdissected with the PALM technology, and identified by using specific primers (Klitgaard et al. 2005). In our study we were able to successfully extract the DNA of the collected cells and use it for further DNA analyses. We have applied an universal bacterial primer set that resulted in an amplicon fragment length short enough for amplification 84 of the extracted DNA but still long enough for reliable phylogenetic classification. Because of the yet low number of collected cells a statistical coverage was not possible. Our preliminary results suggest that Poly-P storage seems to be widespread among sediment bacteria. In summary, DGGE analyses of various freshwater sediments demonstrate that the occurrence of PAO of the Rhodocyclaceae family is an universal feature in many lakes. However, when using CARD-FISH with oligonucleotide probes specific for these PAO it becomes obvious that these bacteria account for only a small fraction of the total bacteria and presumably are insignificant for overall Poly-P storage. Therefore, we have applied a method by which we can identify and separate individual PAO at the same time. The PALM MicroBeam technology coupled with molecular analyses proofed to be an excellent method for the phylogenetic classification of hitherto unknown Poly-P accumulating bacteria from environmental samples. The only precondition of this technique is to visualize the cells of interest for their microscopic detection, e.g. with histological or fluorescent dyes. Cell morphology can be another criterion, too. Additional studies with numbers of collected cells sufficient for statistical analysis are necessary to study the presence and phylogenetic affiliation of PAO in various freshwater systems and to elucidate their ecological role in these systems. Acknowledgement We thank Peter Schmieder for his support with the NMR investigations carried out at the Research Institute of Molecular Pharmacology, Berlin, Germany. Christiane Herzog is acknowledged for her assistance with chemical-analyses and Monika Degebrodt for running the sequencer. Gabriele Friedemann is thanked for introducing SG into the PALM MicroBeam technology. References BOND, P. L., HUGENHOLTZ, P., KELLER, J., BLACKALL, L. L. (1995): Bacterial community structures of phosphate-removing and non-phosphate-removing activated sludges from sequencing batch reactors. Appl. Environ. Microbiol.,61, 1910-1916. BOND, P. L., BLACKALL, L. L., KELLER, J. , WAGNER, M., ERHART, R. (1999): Identification of some of the major groups of bacteria in efficient and nonefficient biological phosphorus removal activated sludge systems. Appl. Environ. Microbiol.,65, 4077-4084. BOSTRÖM, B., ANDERSEN, J.M., FLEISCHER, S., JANSSON,M. (1988) Exchange of phosphorus across the sediment-water interface. Hydrobiologia, 170, 229–244. CROCETTI, G.R., HUGENHOLTZ, P. , BOND, P. L. , SCHULER, A., KELLER, J., JENKINS, D., BLACKALL, L. L. (2000): Identification of PolyphosphateAccumulating Organisms and Design of 16S rRNA-Directed Probes for Their Detection and Quantitation. Appl. Environ. Microbiol.,66, 1175-1182. © IGB 2007 85 DAIMS, H., BRÜHL, A., AMANN, R., SCHLEIFER, K. H., WAGNER, M. (1999) The domain-specific probe EUB338 is insufficient for the detection of all Bacteria: development and evaluation of a more comprehensive probe set. Syst. Appl. Microbiol.,22, 434–444. DAVELAAR, D. (1993): Ecological significance of bacterial polyphosphate metabolism in sediments. Hydrobiologia,253,179-192. DEINEMA, M. H., VAN LOOSDRECHT, M., SCHOLTEN, A. (1985): Some physiological characteristics of Acinetobacter spp. accumulating large amounts of phosphate. Water Sci. Technol.,17,119–125. EIXLER, .S, KARSTEN, U., SELIG, U. (2006): Phosphorus storage in Chlorella vulgaris Trebouxiophyceae, Chlorophyta) cells and its dependence on phosphate supply. Phycologia,45, 53–60. FUHS, G. W., CHEN, M. (1975): Microbiological basis of phosphate removal in the activated sludge processes for the treatment of wastewater. Microb. Ecol.,2,119– 138. GÄCHTER, R., MÜLLER, B. (2003): Why the phosphorus retention of lakes does not necessarily depend on the oxygen supply to their sediment surface. Limnol. Oceanogr.,48, 929–933. GÄCHTER, R., MEYER, J. S. (1993): The role of microorganisms in mobilization and fixation of phos¬phorus in sediments. Hydrobiologia, 253,103–121. GÄCHTER, R., MEYER, J. S., MARES, A. (1988): Contribution of bacteria to release and fixation of phosphorus in lake sediments. Limnol. Oceanogr.,33, 1542–1558. GOLTERMAN, H.L. (2004): The chemistry of phosphate and nitrogen compounds in sediments. Kluwer Academic Publishers, Dordrecht Boston London, 259 pp. HESSELMANN, R. X. P., WERLEN, C., HAHN, D., VAN DER MEER, J. R., ZEHNDER, A. J. B. (1999): Enrichment, phylogenetic analysis and detection of a bacterium that performs enhanced biological phosphate removal in activated sludge. Syst. Appl. Microbiol.,22, 454–465. HÖLL, K. (1930): Über Schlammablagerungen, insbesondere über das Vorkommen von natürlichem belebtem Schlamm und seine Eigenschaften. Zbl. Bakt. Parasitenkd., 81, 198–210. HUPFER, M., GÄCHTER, R., RÜEGGER, H. (1995): Poly-P in lake sediments. 31PNMR spectroscopy as a tool for its identification. Limnol. Oceanogr., 40, 610– 617. HUPFER, M., RÜBE, B., SCHMIEDER, P. (2004): Origin and diagenesis of polyphosphate in lake sediments: A 31P NMR study. Limnol. Oceanogr.,49, 1–10. KAWAHARASAKI, M., TANAKA, H., KANAGAWA, T., NAKAMURA, K. (1999): In situ identification of polyphosphate-accumulating bacteria in activated sludge by dual staining with rRNA-targeted oligonucleotide probes and 4', 6-diamidino2- phenylindol (DAPI) at a polyphosphate-probing concentration. Water Res.,m 33, 257–265. KLITGAARD, K., MOLBAK, L., JENSEN, T. K., LINDBOE, C. F., BOYE, M. (2005): Laser capture microdissection of bacterial cells targeted by fluorescence in situ hybridization. Biotechniques.,6, 864-868. KONG ,Y. H., NIELSEN, J. L., NIELSEN, P. H. (2004): Microautoradiographic study of Rhodocyclus-related polyphosphate-accumulating bacteria in full-scale 86 enhanced biological phosphorus removal plants. Appl. Environ. Microbiol., 70, 5383–5390. KONG, Y. H., NIELSEN, J. L., NIELSEN, P. H. (2005): Identity and ecophysiology of uncultured actinobacterial polyphosphate-accumulating organisms in full-scale enhanced biological phosphorus removal plants. Appl. Environ. Microbiol.,71, 4076–4085. KÜSEL, A. C., SIANOUDIS, J., LEIBFRITZ, D., GRIMME, L. H., MAYER, A. (1989): 31P in vivo NMR investigations on the function of polyphosphates as phosphate-source and energy-source during the regreening of the green alga Chlorella fusca. Arch. Microbiol.; 152; 167–171. LAWERENCE, B. A., SUAREZ, C., DEPINA, A., CLICK, E., KOLODNY, N. H., ALLEN, M.M. (1998): Two internal pools of soluble polyphosphate in the cyanobacterium Synechocystis sp. strain PCC 6308: An in vivo 31P NMR spectroscopic study. Arch. Microbiol. 169:195–200. MASZENAN, A. M., R. SEVIOUR, J., PATEL, B. K. C., SCHUMANN, P., BURGHARDT, J., TOKIWA, Y., STRATTON, H. M. (2000): Three isolates of novel polyphosphate accumulating Gram-positive cocci, obtained from activated sludge, belong to a new genus, Tetrasphaera gen. nov., and description of two new species, Tetrasphaera japonica sp. nov. and Tetrasphaera australiensis sp. nov. Int. J. Syst. Evol. Microbiol.,50, 593-603. MUYZER, G., DEWAAL, E. C., UITTERLINDEN, A. G. (1993): Profiling of complex microbial populations by Denaturing Gradient Gel-Electrophoresis analysis of polymerase chain reaction-amplified genes-coding for 16s ribosomalRNA. Appl. Environ. Microbiol.,59, 695-700. NAKAMURA, K., HIRAISHI, A., YOSHIMI, Y., KAWAHARASAKI, M., MASUDA, K., KAMAGATA. Y. (1995): Microlunatus phosphovorus gen. nov., sp. nov., a new gram-positive polyphosphate-accumulating bacterium isolated from activated-sludge. Int. J. Syst. Bacteriol.,45, 17–22. PERNTHALER, A., J. PERNTHALER, AMANN, R. (2002): Fluorescence in situ hybridization and catalyzed reporter deposition for the identification of marine bacteria. Appl Environ. Microbiol.,68, 3094-3101. REITZEL, K., AHLGREN, J., GOGOLL, A., RYDIN, E. (2006): Effects of aluminium treatment on phosphorus, carbon, and nitrogen distribution in lake sediment: a 31P NMR study. Water Res.,40, 647-654. SIANOUDIS, J., KÜSEL, A. C., MAYER, A., GRIMME, L. H., LEIBFRITZ, D. (1986): Distribution of polyphos¬phates in cell- compartiments of Chlorella fusca as measured by 31P-NMR spectroscopy. Arch. Microbiol.,144, 48–54. STANTE, L., CELLAMARE, C. M., MALASPINA, F., BORTONE, G., TINCHE, A. (1997): Biological phosphorus removal by pure culture of Lampropedia spp. Water Res.,31, 1317–1324. STREICHAN, M., GOLECKI, J. R., SCHÖN, G. (1990): Polyphosphate accumulating bacteria from sewage plants with different processes for biological phosphorus removal. FEMS Microbiol. Ecol.,73, 113–124. UHLMANN, D., RÖSKE, K., ULRICH, K. U., PAUL, L. (1998): Bacteria in the bottom sediment of a drinking water reservoir. Int. Rev. Hydrobiol., 83, 269–280. © IGB 2007 87 WAARA, T., JANSSON, M., PETTERSON, K. (1993): Phosphorus composition and release in sediment bacteria of the genus Pseudomonas during aerobic and anaerobic conditions. Hydrobiologia ,253,131–140. WAGNER, M., ERHART, R., MANZ, W., AMANN, R., LEMMER, H., WEDI, D., SCHLEIFER, K.-H. (1994): Development of an rRNA-targeted oligonucleotide probe specific for the genus Acinetobacter and its application for in situ monitoring in activated sludge. Appl. Environ. Microbiol.,60,792–800. WOBUS, A., BLEUL, C., MAASSEN, S., C. SCHEERER, C., SCHUPPLER, M., JACOBS, E., RÖSKE, I. (2003): Microbial diversity and functional characterization of sediments from reservoirs of different trophic state. FEMS Microbiol. Ecol.,46,331–347. 88 H ELLAND , I.P., B RAUNS M., F REYHOF , J. 3.3.2 Depth distribution of abundant benthic invertebrates in Lake Stechlin Tiefenverteilung von häufigen benthischen Wirbellosen im Stechlinsee Key words: ecological gradient, oligotrophic lake, chironomidae, oligochaeta Abstract Benthic macroorganisms were collected every 5 m depth along an east-west transect from 5 to 50 m, in the northern bay of Lake Stechlin in August 2006. From 18 taxonomic groups recorded, 10 groups were restricted to the first 15 m water depth. Chironomids, oligochaets and Megacyclops copepods are most abundant in all water depth. Species richness and the number of macrobenthic organism declined with increasing water depth. Zusammenfassung Im August 2006 wurden Macrozoobenthos-Organismen alle 5 m entlang eines ost-west Tiefengradienten von 5-50 m in der Nordbucht des Stechlinsees untersucht. Von 18 nachgewiesenen Organismen-Gruppen waren 10 auf die oberen 15 m Wassertiefe beschränkt. Chironomiden, Oligochaeten und Megacyclops copepoden waren die häufigsten Organismen in allen Tiefen. Die Arten-Diversität und die Abundanz der Macrozoobenther nahmen mit zunehmender Tiefe ab. 3.3.2.1 Introduction Benthic macroinvertebrates are of high importance in aquatic environments as link between detrial deposits in the profundal zone and the higher trophic levels. Many fish species are dependent on a benthic diet in shorter or longer parts of their lives (Vander Zanden & Vadeboncoeur 2002), and zoobenthic biomass has been looked upon as an index of the potential productivity of a lake for fish (Rasmussen 1988). It has been suggested that the importance of benthic energy pathways in lake food webs has been overlooked, and that the focus on the pelagic area has been too strong (Vadeboncoeur et al. 2002). Recently, there has been an increasing interest in analysis of how pelagic and benthic habitats are interconnected (e.g. (Harrod & Grey 2006; Okun et al. 2005; Vander Zanden & Vadeboncoeur 2002)). In the littoral, the main food source is attached algae and allochtonous detrial carbon of terrestrial origin, and the benthic community usually is diverse and highly productive. In contrast, the profundal zone may only offer sedimenting autochtonous organic matter as food source (France 1995). Rasmussen & Kalff (1987) found the production of profundal macroinvertebrates to correlate with the trophic status of the lake, and that their biomass is regulated by the level of chlorofyll a and phosphorus. Therefore, allochthonous material and nutrients are more important in oligotrophic lakes than in more productive lakes (Dermott 1988). In oligotrophic lakes surrounded by a dense forest © IGB 2007 89 particularly leaf litter from the nearby vegetation is the important allochtonous detrius material (Oertli 1993; Pieczynska 1993), which influences the macroinvertebrate composition at first, and thereafter the higher trophic levels in the lake. Benthic macroinvertebrates may both be predators on smaller organisms (e.g. cladocerans) and at the same time an important food source for fish, and can therefore operate as key organisms in lacustrine ecosystems (Sagrario & Balseiro 2003). The North German Lake Stechlin is largely dominated by pelagic fishes of the genus Coregonus. While these feed mostly on planctonic prey, Schulz et al. (2003) demonstrated that Lake Stechlin Corgeonus also take a certain amount of benthic organisms. It could even be suggested, that benthic organisms as an alternative to pelagic prey might have played a role in the evolution of the endemic Lake Stechlin cisco Coregonus fontanae (Schulz et al. 2006) and benthic food might be involved in the particular depth distribution if this species (Helland et al. 2007). However, the benthic macrofauna is poorly studied in Lake Stechlin. Therefore, it is the aim of this study to describe the depth distribution of major benthic macroinvertebrates to give a baseline to future studies on food availability for Lake Stechlin fishes. 3.3.2.2 Material and Methods Lake Stechlin is a medium sized (4.25 km2), deep (max. depth 69 m) oligotrophic lake in northern Germany (53°10’N 13°02’E). Invertebrate sampling took place in August 2006 along an east-west transect in the northern bay of the lake (Fig. 1). Within this transect, three replicated invertebrate samples were taken at 20 sampling points from 5 to 50 m water depth using an Ekman-Birge grab (HydroBios, Mondsee, Germany). Samples were sieved in the field (500 µm mesh) and transported on ice to the laboratory. Invertebrates were sorted live to major taxonomic groups at the same day. Copepods were identified by A. Rychla (Neuglobsow). Individuals were measured to the nearest mm using stereo-dissecting microscopes and an object micrometer. The Shannon-Wiener-Index of Diversity was applied to the full set of species data. The following four dominant groups of benthic invertebrates, i.e. > 10 % frequency, were selected for detailed analyses: annelids, white chironomids, red chironomids and copepods (Megacyclops sp.). 90 Fig 1: Bathymetric map Lake Stechlin including marked sample transect. 3.3.2.3 Results 1040 individual animals from 18 taxonomic groups were caught (Table 1). From these, 10 taxonomic groups were restricted to the first 15 m water depth. There was a significant negative regression between the index of diversity and water depth (Fig. 2). Table 2 shows the results of the regression analysis between the abundance of benthic invertebrates and water depth. If all macrobenthic organism are added together, there is a significant negative regression between water depth and the abundance of benthic invertebrates on the west side of the transect only. Within the four dominant taxonomic groups, there were negative, significant regressions between water depth and the number of white chironomids on both lake sides of the transect. Oligochaets showed a significantly negative regression with water depth on the western side and a significantly positive regression on the eastern side of the tansect. The abundance of Megacyclops and red chironomids did not show any clear depth gradient. Generally, species richness and the number of macrobenthic organism declined with increasing water depth. © IGB 2007 91 Tab 1: Benthic animals from three samples each water depth along a transect in Lake Stechlin. Lakeside east Water depth (m) 5 10 15 11 2 5 72 Acari Asellus west Bivalvia 20 3 Ceratopogonidae 25 35 40 45 50 1 4 29 19 12 30 Chironomidae White 4 30 10 1 3 2 1 Cladocera 1 Total 10 15 20 1 6 9 3 3 11 7 25 30 20 22 12 1 1 11 35 40 45 50 32 98 3 1 5 14 19 16 29 34 30 29 10 1 16 12 10 12 8 7 2 2 2 3 4 8 8 6 12 16 374 1 1 120 10 2 Gastropoda 4 3 Hirundinea 1 2 1 3 19 Megacyclops 5 1 2 Chironomidae Red Ephemeroptera 30 4 Nematoda 7 11 22 2 7 1 8 3 2 2 6 8 26 13 1 4 2 2 2 1 Odonata 1 Oligochaeta 2 8 Ostracoda 1 6 1 4 9 8 2 13 14 7 1 21 1 Turbellaria 1 1 Total 24 174 64 21 43 22 45 5 26 33 7 1 13 6 2 4 7 1 Sialis Trichoptera 103 30 20 2 3 13 1 5 7 193 22 8 1 3 3 2 1 4 5 42 96 112 95 66 1 3 2 42 43 28 18 11 23 39 1040 92 © IGB 2007 Tab 2: Regression of total number of individuals of the dominant taxonomic groups against water depth. Lakeside east & west Significance (p) & coefficient of regression (R) p east R west p R p R -0.687 All species 0.002 -0.395 0.177 -0.253 <0.001 Oligochaeta 0.404 -0.110 0.033 0.390 0.010 -0.463 Megacyclops 0.072 -0.234 0.393 -0.162 0.117 -0.292 Red chironomids 0.207 -0.165 0.766 -0.058 0.148 -0.271 White chironomids 0.001 -0.501 0.031 -0.394 <0.001 -0.792 1.0 0.9 0.8 0.7 Index of 0.6 diversity 0.5 0.4 0.3 0.2 0.1 0.0 5 10 15 20 25 30 35 40 45 50 50 45 40 35 30 water depth (m) Fig 2: Index of diversity calculated for benthic macroinvertebrates along a depth transect in Lake Stechlin. 25 20 15 10 5 93 3.3.2.4 Discussion The far most dominant groups of macroinvertebrates found in Stechlinsee were chironomids and oligocheata, a pattern which is frequently found in lakes (e.g (Dinsmore et al. 1999; Lindegaard 1992; Oertli 1993). These were the only organisms occurring at all sampled depths in our study. The Megacyclops copepods, which were also abundant, were found from 10 to 50 metres, but were most abundant between 10 and 20 metres. Generally, the abundance of benthic organisms declined with increasing water depth and therefore, benthic organisms as a food resource are less profitable to exploit in deeper waters. However, this does not mean, that benthic organisms might not be a profitable prey in deep waters. The most important factors found to shape littoral macroinvertebrate communities are nutrient level, wind exposure, substrate type and vegetation cover (Brodersen 1995; Tolonen et al. 2001). Most of the animal groups were found only in the first 15 m water depths and the higher diversity in the nearshore area might be related to the high amount of leaves and terrestrial input from the dense forest around the lake. The differences found between the eastern and western side might be due to wind and wave exposure. There is a quite sharp slope at the shore at both sides of the transect and the depth increases rapidly, which probably gives rather small amounts of macrophytes. Macrophytes are expected to give macrozoobenthos substrate and food (Rasmussen 1988). Yet, the littoral in Stechlinsee might have large amounts of wood and terrestrial vegetation falling into or partly growing in the littoral of the lake. Leaf litter can potentially be of high quality for macroinvertebrates and give larger macroinvertebrate production than other substrate types such as macrophytes (Oertli 1993). Chironomids are known to be essential in the macroinvertebrate community and can account for as much as 75-95% of the benthic secondary production in lakes surrounded by wood (Lindegaard 1992; Oertli 1993). Chironomids are know to be an important food source for many fish species, and they are therefore important for the energy transfer through the food web in the lake system. In Stechlinsee chironomids, ostracods, Trichoptera and Megacyclops have been found in the diet of the two coregonid fish species Coregonus albula and Coregonus fontanae (Schulz et al. 2003) but future studies need to demonstrate, how important benthic organisms are as a food resource for Lake Stechlin Coregonus and whether there are individual differences between fish that exploit the benthic resource compared to the planctonic food resource. Acknowledgement We are very thankfull to Humboldt and Freie Universität students M. Albers, C. Aßmann, K. Felsmann, C. Jessen, N. Jobstvogt, B. Stelbrink, M. Zadow (all Berlin) who helped in the field and laboratory to collect and sort out the samples. Copepods were identified by A. Rychla (Neuglobsow). 94 References BRODERSEN, K. P. (1995): The Effect of Wind Exposure and Filamentous Algae on the Distribution of Surf Zone Macroinvertebrates in Lake Esrom, Denmark. Hydrobiologia, 297.2., 131-148. DERMOTT, R. M. (1988): Zoobenthic Distribution and Biomass in the Turkey Lakes. Canadian Journal of Fisheries and Aquatic Sciences, 45.107-114. DINSMORE, W. P., SCRIMGEOUR, G. J., PREPAS, E. E. (1999): Empirical relationships between profundal macroinvertebrate biomass and environmental variables in boreal lakes of Alberta, Canada. Freshwater Biology, 41.1., 91-100. FRANCE, R. L. (1995): Empirically estimating the lateral transport of riparian leaf litter to lakes. Freshwater Biology, 34.3., 495-499. HARROD, C., GREY, J. (2006): Isotopic variation complicates analysis of trophic relations within the fish community of Plu beta see: a small, deep, stratifying lake. Archiv fur Hydrobiologie, 167.1-4., 281-299. HELLAND, I. P., FREYHOF, J., KASPRZAK, P., MEHNER, T. (2007): Temperature sensitivity of vertical distributions of zooplankton and planktivorous fish in a stratified lake. Oecologia, 151.2., 322-330. LINDEGAARD, C. (1992): The Role of Zoobenthos in Energy-Flow in Deep, Oligotrophic Lake Thingvallavatn, Iceland. Hydrobiologia, 243.185-195. OERTLI, B. (1993): Leaf-Litter Processing and Energy-Flow Through Macroinvertebrates in A Woodland Pond (Switzerland). Oecologia, 96.4., 466477. OKUN, N., LEWIN, W. C., MEHNER, T. (2005): Top-down and bottom-up impacts of juvenile fish in a littoral reed stand. Freshwater Biology, 50.5., 798-812. PIECZYNSKA, E. (1993): Detritus and Nutrient Dynamics in the Shore Zone of Lakes - A Review. Hydrobiologia, 251.1-3., 49-58. RASMUSSEN, J. B. (1988): Littoral Zoobenthic Biomass in Lakes, and Its Relationship to Physical, Chemical, and Trophic Factors. Canadian Journal of Fisheries and Aquatic Sciences, 45.8., 1436-1447. RASMUSSEN, J. B., KALFF, J. (1987): Empirical-Models for Zoobenthic Biomass in Lakes. Canadian Journal of Fisheries and Aquatic Sciences, 44.5., 990-1001. SAGRARIO, M. D. G., BALSEIRO, E. (2003): Indirect enhancement of large zooplankton by consumption of predacious macroinvertebrates by littoral fish. Archiv fur Hydrobiologie, 158.4., 551-574. SCHULZ, M., FREYHOF, J., SAINT-LAURENT, R., OSTBYE, K., MEHNER, T., BERNATCHEZ, L. (2006): Evidence for independent origin of two springspawning ciscoes (Salmoniformes: Coregonidae) in Germany. Journal of Fish Biology, 68.s1., 119-135. SCHULZ, M., KASPRZAK, P., ANWAND, K., MEHNER, T. (2003): Diet composition and food preference of vendace (Coregonus albula (L.)) in response to seasonal zooplankton succession in Lake Stechlin. Archiv für Hydrobiologie, Special Issues Advances in Limnology, 58.215-226. TOLONEN, K. T., HAMALAINEN, H., HOLOPAINEN, I. J., KARJALAINEN, J. (2001): Influences of habitat type and environmental variables on littoral macroinvertebrate communities in a large lake system. Archiv fur Hydrobiologie, 152.1., 39-67. © IGB 2005 95 VADEBONCOEUR, Y., VANDER ZANDEN, M. J., LODGE, D. M. (2002): Putting the lake back together: Reintegrating benthic pathways into lake food web models. Bioscience, 52.1., 44-54. VANDER ZANDEN, M. J., VADEBONCOEUR, Y. (2002): Fishes as integrators of benthic and pelagic food webs in lakes. Ecology, 83.8., 2152-2161. 96 3.4 Research Topic 4 Forschungsschwerpunkt 4 Sustainable management of aquatic ecosystems Nachhaltiges Gewässermanagement © IGB 2007 97 98 G ARCIA , X.-F., G ABEL , F., H OCHMUTH , H., B RAUNS , M., S UKHODOLOV , A., P USCH , M. 3.4.1 Do littoral habitats with high structural complexity mitigate the impact of ship-induced waves on benthic invertebrates? Reduzieren litorale Habitate mit hoher struktureller Komplexität die Auswirkungen schiffsinduzierten Wellenschlags auf benthische Wirbellose? Key words: shear stress, detachment rate, threshold, fractal dimension, inland navigation Abstract Ship-induced waves constitute a major threat to macroinvertebrate communities inhabiting littoral zones of lakes and rivers. However, factors influencing the detachment of invertebrates by waves were never addressed nor quantified. Hence, we investigated the interaction between structural complexity of littoral habitats and waveinduced hydraulic disturbance on invertebrates. In an experimental wave tank, five species were exposed to waves of different shear stress (4.3 - 21.9 dyn/cm2) in five littoral habitats, and in reed stands of four different densities, representing various levels of structural complexity. The number of detached invetebrate individuals depended significantly on the applied shear stress. Detachment rate averaged for the five species was significantly lower in habitats with a high degree of structural complexity, decreasing in the habitat sequence sand, coarse woody debris, stones, reed and tree roots, and accordingly with increasing reed densities. Response thresholds to hydraulic stress differed between species according to the habitat, as species-specific fixing or hiding capabilities matched specific physical habitat characteristics. Besides offering good sheltering conditions for invertebrates, high structural complexity of the habitat also increased dissipation of the waves’ kinetic energy. Consequently, the adverse effects of boat traffic on littoral invertebrate assemblages is drastically increased as soon as complex littoral habitats like tree roots or dense reed belts disappear by wave action or adverse lakeshore management practices. Zusammenfassung Schiffsinduzierter Wellenschlag stört die an See- und Flussufern lebenden Wirbellosengemeinschaften in erheblichem Umfang. Bisher wurden aber die Faktoren, die die Verdriftung der Invertebraten durch Wellen beeinflussen, weder benannt noch quantifiziert. Daher wurden die Auswirkungen der Wechselwirkungen zwischen der strukturellen Komplexität der Uferlebensräume und der welleninduzierten hydrodynamischen Störung auf Wirbellose untersucht. In einem Wellenkanal wurden in Experimenten Wellenhöhen mit unterschiedlicher Sohlschubspannung (4,3 – 21,9 dyn/cm²) erzeugt, die auf fünf Wirbellosenarten in fünf verschiedenen Habitattypen sowie in Schilfbeständen mit vier unterschiedlichen Halmdichten einwirkten. Die © IGB 2007 99 unterschiedlichen Habitattypen und die Schilfdichten stellten einen Gradienten der strukturellen Habitatkomplexität dar. Die Anzahl an verdrifteten Wirbellosenindividuen hing signifikant von der einwirkenden Sohlschubspannung ab. Die über die fünf Wirbellosenarten gemittelte Verdriftungsrate war in Habitaten mit einem hohen Grad an struktureller Komplexität signifikant geringer. Sie nahm in der Reihenfolge Sand, Totholz, Steine und Schilf zu Wurzeln hin ab, ebenso auch mit zunehmender Schilfdichte. Außerdem unterschieden sich die Reaktions-Schwellenwerte der untersuchten Arten hinsichtlich des hydrodynamischen Stresses in den einzelnen Lebensräumen, in Abhängigkeit von Übereinstimmungen der artspezifischen Festhalte- oder Versteckfähigkeiten mit den entsprechenden Möglichkeiten der getesteten Lebensräume. Somit bietet eine erhöhte strukturelle Komplexität einerseits bessere Festhaltemöglichkeiten für Wirbellose, und führt andererseits auch zu einer Dissipation der Wellenenergie. Infolgedessen erhöhen sich die negativen Auswirkungen des schiffsinduzierten Wellenschlags auf litorale Wirbellosengemeinschaften drastisch, wenn komplexe Habitate, wie Wurzeln oder dichte Schilfbestände, aufgrund von Wellenschlag oder uferbaulichen Maßnahmen verschwinden. 3.4.1.1 Introduction Inland navigation by freight barges, passenger ships and recreational boats produces ship-induced waves which are characterised by strong amplitudes, frequent occurrences, short-term increase of flow velocity and which affect wind-sheltered littoral zones as well (Bhowmik & Mazumder 1990, Rodriguez et al. 2002). As a consequence, ship-induced waves are expected to be a major hydraulic disturbance for organisms inhabiting the littoral zones of lakes, rivers and canals used as inland waterways. To date, the impact of ship-induced waves on shore assemblages has been documented by very few published studies. Bishop & Chapman (2004) provided evidence that abundance of estuarine benthic invertebrates inhabiting intertidal sediments were lower in boat-wash zones by comparison to non boat-wash zones. Similarly, Holland (1986) observed an eggs mortality of 20 to 50% in fish communities due to tows passing by on the Mississippi River. However, focusing on single individuals, little is known so far about potential thresholds in the response of littoral invertebrates to anthropogenic wave disturbance of increasing shear stress, or about the interaction with habitat properties. In particular, the factors influencing the extent to which invertebrates are detached by waves in specific littoral habitats have never been addressed, either in natural or under experimental conditions. The only evidence published so far comes from a related case with stream invertebrates exposed to continuous flow. Flume experiments demonstrated that current-induced drift of lotic invertebrate species increased with increasing flow velocities (Borchardt 1993, Imbert 1999). High habitat structural complexity is known to increase biomass, abundance and diversity in benthic invertebrate communities (O’Connor 1991, Schmude 1998, Beck 2000, Taniguchi et al. 2003, Taniguchi & Tokeshi 2004). Consequently, the complexity of the 3-dimentional structure of the habitat is expected to also be a key component in reducing hydraulic stress on benthic invertebrate. Already, Borchardt (1993) in his experiments on current-induced drift showed that the proportion of drifting individuals decreased when more and more woody debris was added to sand habitat. In 100 the current study, we investigated the resistance of invertebrate species to increasing wave disturbance for habitats of different degrees of structural complexity, in order to assess how physical characteristics of littoral habitats mitigate the adverse effect of ship-induced waves on benthic invertebrates. Using two distinct experimental set-ups, we mutually considered the nature (habitat-types) and the density of the habitat structures, two complementary components of the habitat structural complexity. We hypothesized that (i) the proportion of detached individuals directly depends on the level of shear stress associated with the wave; (ii) the proportion of detached individuals also depends on species-specific adaptations to certain habitats, and (iii) the number of detached individuals decreases with higher habitat structural complexity. 3.4.1.2 Methods In an experimental wave tank (L: 3 m, W: 0.80 m and H: 0.60 m) five invertebrate species (Bithynia tentaculata, Calopteryx splendens, Dikerogammarus villosus, Gammarus roeseli and Laccophilus hyalinus) were exposed to single waves of increasing strengths (shear stress range: 4.3 - 21.9 dyn/cm2) in natural habitats representing various levels of structural complexity. Two series of experiments were conducted. In the first series, the five invertebrate species were exposed in five different littoral habitats [sand, coarse woody debris (CWD), stones, reed, and tree roots]. In the second series, the same five species were exposed in reed habitats of four different stem densities (45, 127, 175 and 250 stems/m²), depicting a comparable gradient of structural complexity than the five habitats. The structural complexity of the habitats was quantified by their fractal dimension (FD), calculated following the Frontier’s grid method (Frontier 1987) on sizecomparable top-view digital pictures of the habitat trays. The frame of the habitat tray was taken as the first square of the grid, which was progressively split into half-sized finer grids until reaching a level of 4,096 squares. On each grid level the proportion of squares entered with an edge of a habitat component was set into relation to the total number of squares in one row. The slope of the log transformed relationship gave value for the FD. Prior experiments were conducted to test the stability and reproducibility of the hydraulic conditions in the wave tank when producing waves. Hence, the 10 different wave strength levels possibly produced were significantly different from each other (ANOVA with Post-Hoc test, Scheffé procedure, N=10, p=0.023 at the lowest) and reproducible in time (coefficient of variance: 0.36 - 2.17 %, N=10 per strength level). Flow motion was approximately unidirectional, vertically and laterally uniform (ANOVA, N=10 per test, p>0.05 for all tests) with almost null values of vertical and lateral velocities, supporting the conditions of a laminar flow. Consequently, wave strength was expressed by the bottom shear stress τ (dyn/cm2) caused by the wave at the location of the habitat (1), calculated using the wave friction factor () formula given by Dyer (1986) for laminar flow (2): © IGB 2007 W 0.5 fUU b2 f 2 Q UbAb : wave friction factor density of water (1 g/cm 3 ) U b : maximum wave orbital velocity (cm/s) (measured by an acoustic Doppler velocimeter, 50 Hz) (2) A b : maximum bottom wave amplitude (cm) (measured by an acoustic wave sensor, 20 Hz) Q: water viscosity (~0.01 cm²/s) (1)ρ: 101 The five habitats and species selected were common for the littoral zones of northeastern German lakes. Beside, species were also chosen to depict contrasted body shapes and behaviors, which should influence their fixing and hiding capabilities. The designing of the habitats in the wave tank (two trays of 0.115 m² area each) followed spatial arrangements and densities commonly observed in natural conditions. The habitat structural complexity increased in the following sequence: sand (FD=1), CWD (1.30), stones (1.34), reed175 (1.39) and roots (1.80) for habitats and reed45 (FD=1.02), reed127 (1.29), reed175 (1.39) and reed250 (1.45) for habitat densities. The energy lost by the wave when passing through the habitat was quantified as the shear stress difference in front and behind the habitat, for incoming waves of three different shear stress levels (13.7, 16.4 and 19.8 dyn/cm2). For each experiment (= one habitat-species combination), 20 individuals of similar body size were exposed to three replicated waves per shear stress level, with a time interval of 15 minutes. Wave strength was increased until 100% of the individuals were dislodged or the maximum applicable shear stress reached. For each wave produced, wave velocity, wave amplitude and the number of individuals detached from the habitat (counted from video records) were recorded. 3.4.1.3 Results and discussion For the five species exposed to waves, a similar pattern of increasing number of detached individuals in relation to increasing shear stress was observed in sand, CWD, stones (Fig. 1A) and in the four reed habitats differing in stem density (Fig. 1B). These relationships could be well described by sigmoide regression models (Table 1) which were all significant except for B. tentaculata on stones and reed45 and from C. splendens in reed250. Conversely, such pattern was not observed in root habitat, the most complex habitat, from which only few individuals of each species were detached by the strongest waves. The strength of this relationship varied however according to the species-habitat combination considered Table 1. Regression coefficients (r²) and significance levels (*** p<0.001, ** p<0.01, * p<0.05, n.s. non significant) of the sigmoid regression models describing the total number of detached individuals in each habitat as a function of the shear stress caused by experimental waves. CWD Reed250 0.81*** 0.48* 0.76*** 0.78*** 0.64* 0.04ns 0.92*** 0.96*** Stones 0.81*** 0.52* 0.99*** 0.02 n.s. 0.81*** 0.66* 0.05 n.s. 0.97** 0.79*** 0.86*** Dikerogammarus villosus 0.84*** 0.06 n.s. 0.79*** 0.56** 0.61** 0.92*** Gammarus roeseli 0.92*** - 0.71** 0.88*** 0.87*** 0.80*** 0.94*** 0.93*** Laccophilus hyalinus 0.85** 0.12 n.s. 0.99*** 0.94*** 0.99*** 0.98*** 0.89*** 0.95*** Calopteryx splendens 102 Reed175 Sand Bithynia tentaculata Reed45 Reed127 Roots (A) (B) Fig.1. Number of detached individuals as a function of the shear stress caused by experimental waves. (A) in each habitat for C. splendens and G. roeseli, (B) for each species in CWD and reed 250 . Plotted values represent mean number of detached individuals (± SE) for three replicated waves. The comparison of the total numbers of detached individuals averaged for the five species (mean ± SE) showed that more individuals were detached in sand (130.2 ± 6.8) than in CWD (67.5 ± 9.5), stones (60.5 ± 11.3), reed (48.6 ± 11.2) and roots (4.7 ± 1.6) (Fig. 2A). Total number of detached individuals was significantly different between sand and all other habitats (ANOVA with Post-Hoc test, Scheffé procedure, N=75, p<0.01) as well as between roots and all other habitats (p=0.002 at the lowest). No significant differences of the total number of detached individuals were observed between CWD, stones and reed (p>0.05 for the three tests). Similarly, less individuals were detached when reed stem density increased (respectively: 83.1 ± 22.2, 71.9 ± 21.5, 48.6 ± 20.9 and 44.1 ± 19.6 - Fig. 2B). Significant differences were recorded between reed densities of 45 - 127 stems/m² in one side and reed densities of 175 - 250 stems/m² in the other side (ANOVA, with Post-Hoc test, Scheffé procedure, N=60, p<0.05). Obviously, sand habitat did not offer appropriate hiding or fixing spots for any of the five species while the dense network of tiny and flexible branches constituting the root bunch allowed every species, irrespectively its size or gripping strategy, to enter the bunch and fix itself efficiently. More generally, the detachment of invertebrates by wave-induced hydraulic disturbance is significantly reduced in complex habitats, as more complex habitats provide more refuges and anchorage points that enable individuals to resist drag forces imposed by peaks in flow velocity. © IGB 2007 103 140 160 a (A) 120 100 100 b 80 b b 60 (B) 140 120 dasfier Total number of detached individuals 160 a a b 80 b 60 40 40 20 c 20 0 0 Sand CW D Stones Reed175 Reed45 Roots Reed127 Reed175 Reed250 Fig. 2. Total number (mean ± SE for the five species) of detached individuals for (A) each habitat and (B) each reed density. Bars with different letters indicate significant differences among habitats. Considering each species separately, strong disparities were observed in the total number of detached individuals between habitats, revealing a species-specific response to wave-induced hydraulic disturbance according to habitats (Tab. 2). Indeed, it is obvious that the degree of detachment of invertebrates depends on how speciesspecific fixing or hiding capabilities matched specific physical habitat characteristics. For example, the rough ridges of CWD provided good anchorage points for species fixing themselves with big claws like C. splendens and D. villosus, but not for the snail B. tentaculata, which needs smoother surfaces as reed stems to suck efficiently, neither for G. roeseli and L. hyalinus which possess smaller claws (see Fig. 2B). Beside, the attraction exerted by the habitat on the individuals also depends on how the size of the refuges defined by the habitat structure matches the size of organism body (Taniguchi & Tokeshi 2004). Tab. 2: Total number (mean ± SE, N=3) of detached individuals for the cross combinations of species and habitats studied. CWD Bithynia tentaculata Calopteryx splendens Dikerogammarus villosus Gammarus roeseli Laccophilus hyalinus 80.0 ± 1.5 29.7 ± 1.2 29.0 ± 0.6 74.7 ± 0.9 124.3 ± 1.5 Roots 8.0 ± 0.6 0.3 ± 0.3 0.3 ± 0.3 0.0 ± 0.0 14.7 ± 0.9 Sand 124.3 ± 3.2 166.3 ± 0.3 100.7 ± 1.4 100.8 ± 2.5 151.7 ± 1.8 Stones Reed 45 Reed 127 Reed 175 Reed 250 22.3 ± 0.9 65.0 ± 2.6 9.0 ± 1.2 79.0 ± 1.7 127.3 ± 2.0 16 ±3 68 ± 1.2 73.3 ± 2.9 109.3 ± 1.5 149 ± 3.7 8 ± 1.7 48 ± 1.5 70.7 ± 2.4 98.7 ± 0.6 134 ± 2.9 12.3 ± 0.3 8.0 ± 2.1 47.3 ± 1.2 50.7 ± 4.9 124.7 ± 2.3 12.3 ±3 3.7 ± 0.9 40.3 ± 1.5 49.3 ± 0.3 115 ± 1.2 In order to take into account this heterogeneity in species response, we tested using a multiple classification analysis (MCA, Andrews et al. 1973), how far differences in individuals detachment rates observed between habitats were influence by either species or habitat. MCA examines the interrelationship between several predictor variables and one dependant variable and provides the part of explained variance by each predictor, both before and after taking into account the effects of all other 104 predictors. MCA revealed that 55.8% of the variance in maximum number of detached individuals was explained by differences in habitats (value corrected from the influence of the species factor) against 20.8% by differences between species (value corrected from the influence of the habitat factor - r²model = 0.77, p<0.001, N=75). Similarly, differences in reed density explained 76.6% of the overall variance in maximum number of detached individuals against 17.8% explained by differences in species (r²model = 0.94, p<0.001, N=60). In the latest, B. tentaculata and L. hyalinus were removed as they were respectively few and always dislodged from reed habitats, thus not contributing to any variance. Hence, despite contrasted species-specific responses according to habitats, nature and density of the habitat have the strongest influence on detachment rates in wave experiments Consequently, the impact of the wave-induced hydraulic disturbance on invertebrates was found to significantly decrease along the overall gradient of structural complexity depicted by the different habitats (Spearman´s rho = - 0.99, p<0.001, N=8, Fig. 4A). Comparable influences of habitat complexity in sheltering benthic invertebrates against hydraulic disturbance have been similarly demonstrated for Seratella ignita and Gammarus pulex exposed to high currents (Borchardt 1993). In this study, the proportion of individuals drifted away decreased when more and more woody debris was added to the sandy bottom of the circular flume. Shear stress reduction (dyn/cm²) 12 d (A) 12 10 10 8 8 6 4 a b c (B) 6 b,c 4 a a,b b Reed127 Reed175 b 2 2 0 0 Sand CW D Stones Reed175 Roots Reed45 Reed250 Fig. 3: Shear stress reduction (mean ± SE) for an incoming shear stress level of 22 dyn/cm². (A) in the five habitats, (B) for the four reed densities .Bars with different letters are significantly different. In addition to provide fixing possibilities for the invertebrates, structural habitat complexity also affects flow motion in the surroundings of the habitats. For all habitats, shear stress recorded behind the habitat was significantly lower than in front of the habitat (paired t-test, N=10 per test, p<0.001 at the lowest). Comparing the shear stress reduction due to habitats, significant differences in shear stress reduction were recorded between sand and stones, sand and reed and between roots and the other habitats (ANOVA, Post-Hoc tests, Scheffé procedure, N=50, p=0.014 at the lowest, Fig. 3A) as well as between reed45 and reed175 and reed250 (N=40, p=0.021 at the lowest, Fig. 3B). Shear stress reduction was found to be significantly correlated with the structural complexity of the habitat (Spearman´s r = 0.97, p<0.001, N=8 - Fig. 4B). This result matches findings of Atilla et al. (2005) who found reduced flow velocities and lower Reynold’s numbers behind more complex brushes than behind less complex ones. From the perspective of flow mechanics, the structure of the habitat provides obtrusions to the unidirectional flow which generates cross flow motions such as turbulences. In turbulent flows, the kinetic energy of the flow is extracted by the larger © IGB 2007 105 vortices from the mean flow, transferred by the cascade of turbulences towards the smaller scales, where it finally dissipates into heat due to molecular viscosity (Tennekes & Lumley 1972). Correspondingly, higher structural complexity provides more obstacles to flow and dissipates a larger portion of kinetic energy. Total number of detached individuals 140 (A) Spearman r = - 0.99, p<0.001 120 100 80 60 40 20 0 1,0 1,2 1,4 1,6 1,8 2,0 Fractal dimension (FD) Shear stress reduction (dyn/cm²) 10 (B) Spearman r = 0.97, p<0.001 9 8 7 6 5 4 3 2 1 0 1,0 1,2 1,4 1,6 1,8 2,0 Fractal dimension (FD) Fig.4. Relationships between the fractal dimension of the habitats and (A) the total number (mean ± SE for the five species) of detached individuals, (B) the shear stress reduction (mean ± SE for three incoming shear stress levels: 13.7, 16.4 and 19.3 dyn/cm²) caused by the habitats. 3.4.1.4 Conclusion In this study, experimental evidence on the ecological effect of artificial wave disturbance was collected by systematically varying wave energy, habitat complexity and species-specific characteristics under standardized conditions. The complex interactions between species and their habitat preferences were taken into account by using a set of natural habitats as well as species differing in body shapes and fixing capabilities. Also, the nature and the density of habitat structures both contributing to the overall habitat structural complexity were mutually considered. High structural complexity of habitats proved to be related with good sheltering conditions for invertebrates against hydraulic disturbance. This relationship could be 106 causally explained, as high structural complexity provided more refuges or anchorage points for the invertebrates, and as it reduced substantially wave kinetic energy. The conclusions drawn from this indoor experimental study most probably also apply in natural conditions. Waves produced in the wave tank reached maximum flow velocities up to 51 cm/s. However, 50% of the individuals were already detached at shear stress values of 6-15 dyn/cm², which correspond to flow velocities of 19-42 cm/s. By comparison, flow velocities measured in the field on Lake Langer See and on the River Spree (Berlin, Germany) ranged from a minimum of 21-44 cm/s for small private boats to a maximum of 324 cm/s for freight barges and sight-seeing passenger ships. Hence, the comparison of laboratory and field hydrodynamic conditions indicates that the detachment of organisms may be even stronger in natural conditions than demonstrated by our experiments, and probably the most important factor acting on the invertebrate assemblages exposed to ship-induced waves, even for wave of low energy. Thresholds for ship-induced shear stress were nevertheless identified that were still tolerated by most of the invertebrates studied. These thresholds were the lowest in sand habitat (4-8 dyn/cm²), higher in the other habitats (14-16 dyn/cm²) and not reached for roots at the maximum shear stress level we were able to produce in the wave tank (21.9 dyn/cm²). It can be concluded that network habitats such as tree roots, and to a certain extent also dense reed belts, provide efficient protection of invertebrates against wave-induced disturbance. Consequently, complex habitats such as tree roots and dense reed belts must be protected in order to preserve a diverse and natural fauna in the littoral zone of inland waterways, as required by water policies. References ANDREWS, F.M., MORGAN, J.N., SONQUIST J.A., KLEM, L. (eds.) (1973): Multiple Classification Analysis. Second edition. Ann Arbor: Institute for Social Research, University of Michigan. ATILLA, N., FLEEGER, J.W., FINELLI, C.M. (2005): Effects of habitat complexiy and hydrodynamics on the abundance and diversity of small invertebrates colonizing artificial substrates. Journal of Marine Research63: 1151-1172. BECK, M. W. (2000): Seperating the elements of habitat structure: independent effects of habitat complexity and structural complexity and structural components on rocky intertidal gastropods. Journal of Experimental Marine Biology and Ecology 249: 29-49. BHOWMIK N.G., MAZUMDER B.S. (1990): Physical forces generated by barge-tow traffic within a navigable waterway. In: Hydraulic Engineering (Eds H.H. Chang & J.C. Hill), pp. 604-609. American Society of Civil Engineers, New York, USA. BISHOP, M.J., CHAPMAN, M.G. (2004): Managerial decisions as experiments: an opportunity to determine the ecological impact of boat-generated waves on macrobenthic infauna. Estuarine Coastal and Shelf Science 61: 613-622. DYER, K.R. (1986): Coastal and estuarine sediment dynamics. Chichester: Wiley. FRONTIER, S. (1987): Application of fractal theory to ecology. In P. Legendre & L. Legendre (Eds.), Development in Numerical Ecology, NATO ASI Series Vol. G4:335-378, Berlin, Springer. © IGB 2007 107 HOLLAND, L.E. (1986): Effects of barge traffic on distribution and survival of ichthyoplankton and small fishes in the upper Mississippi River. T. Am. Fish. Soc. 115(1): 162-165. O’CONNOR, N.A. (1991): The effects of habitat complexity on the macroinvertebrates colonising wood subsrates in a lowland stream. Oecologia 85: 504-512. RODRIGUEZ J.F., ADMIRAL D.M., LOPEZ F., GARCIA M.H. (2002): Unsteady bed shear stresses induced by navigation: laboratory observations. Journal of Hydraulic Engineering, 128, 515-526. SCHMUDE, K.L. (1998): Efects of habitat complexity on macroinvertebrate colonization of artificial substrates in north temperate lakes. Journal of Northa American Benthological Society 17: 73-80. TANIGUCHI, H., NAKANO, S., TOKESHI, M. (2003): Influences of habitat complexity on the diversity and abundance of epiphytic invertebrates on plants. Freshwater Biology 48: 718-728. TANIGUCHI, H., TOKESHI, M. (2004): Effects of habitat complexity on benthic assemblages in a variable environment. Freshwater Biology 49:1164-1178. TENNEKES, H., LUMLEY, J.L. (1972): A first course in turbulence. Cambridge, Massachusetts, MIT Press. 108 K OSCHEL , R., B EHRENDT , H., H UPFER , M. 3.4.2 Integrated protection of surface waters 1 Integrierter Gewässerschutz von Binnengewässern Key words: ecotechnolgy, eutrophication, freshwater management, protection of waters, water pollution Abstract Highly efficient measures for freshwater ecosystem protection require complex actions. Surface waters are closely connected to their terrestrial and atmospheric environment, and therefore, preventive protection of surface waters begins in the catchment. Improvements and stabilisation of aquatic ecsystems by reduction of point and diffuse loading (redevelopment) must be balanced increasingly with structural optimisation of ecosystems (restoration and ecotechnology), and must be based on a strategy of “integrated management”. Limited financial resources for surface water protection demand an optimal combination of the principles of emissions and imissions. Zusammenfassung Binnengewässer sind empfindliche Indikatoren für Störungen der natürlichen Stoffkreisläufe, weil sie sehr eng mit der terrestrischen Umgebung, dem Grundwasser und der Atmosphäre verbunden sind. Zu den weltweit häufigsten Gewässerproblemen, die die Nutzung der Ressource Wasser erheblich beeinträchtigen, gehören die Eutrophierung, die Versauerung, die Kontamination mit Schadstoffen und die Versalzung. Eine Beseitigung von Gewässerschädigungen und ein effektiver Gewässerschutz erfordern integrative Ansätze, zu dem verschiedene Fachdisziplinen einen Beitrag leisten müssen. Da die Gewässer und die Einzugsgebiete wegen ihrer vielfältigen Struktur ganz unterschiedlich auf Stressfaktoren reagieren und Belastungen kompensieren können, scheint eine alleinige Orientierung auf die Reduzierung von Emissionen auch mit Blick auf die begrenzten finanziellen Mittel für den Gewässerschutz nicht sinnvoll. Stattdessen sollte die gezielte Optimierung der Struktur ökologischer Systeme Bestandteil eines modernen Gewässerschutzes sein. Dazu gehören im Einzugsgebiet eine ressourcenschonende Bewirtschaftung landwirtschaftlicher Flächen und die Revitalisierung von Pufferökosystemen, die als Stoffsenken in der Landschaft wirken. Im Gewässer selbst können durch ökotechnische Verfahren erwünschte Funktionen besonders gefördert werden. Für die Durchführung solcher Optimierungsstrategien fehlen teilweise aber noch die naturwissenschaftlichen Grundlagen und geeignete Vorhersageinstrumente. Sehr große Defizite gibt es bei der ökonomischen Bewertung ökologischer 1 © IGB 2007 changed version after Koschel et al. 2005, Koschel et al. 2007 109 Gewässerfunktionen und bei der Erforschung sozio-ökonomischer Konsequenzen, die ein langfristig angelegter Gewässerschutz erfordert. 3.4.2.1 Surface waters are our future The surface waters are essential and precious resources worthy of protection. They have to be regarded as i) economic goods – referring to their manifold functions within landscape water budgets, ii) part of the food supply – as drinking water, and iii) buffer and service systems – because of their high biological diversity. These three aspects act in concert, and determine the goals of integrated water protection and sustainable management of water resources. World-wide, surface waters, soils, and atmosphere are considered to be severely changed and destabilised by natural fluctuations and diverse human uses (industry, municipal water supply, agriculture) as well as unbalanced management (WBGU 1999). Standing and running waters are especially susceptible to eutrophication, soil erosion, toxic loads, increase in salinity, and acidification. In addition, widespread disturbances of the natural chemical cycles have emerged, and it is presently difficult to estimate the consequences for the water resources. The multiple integrations of the ecosystems with natural cycles can become strongly reduced, and may, in part, vanish. In the journal »Nature«, the paper »The value of the world’s ecosystem services and natural capital« was published in 1997 (Constanza et al. 1997). The authors tried to evaluate the non-cost functions of ecosystems, and calculated the annual services of lakes and rivers to amount to US$ 850,000 for one km-2 water surface. Furthermore, the authors highlighted the meaning of surface waters for water supply, self-purification, and recreation. According to their evaluation, standing and running waters alone support communal services by as much as US$ 1.7 trillion per year, a sum equal to 10% of the world’s gross economic product. These values exemplify the importance of sustaining the above mentioned non-cost services, and that from the economic point of view, it is useful to counteract the degradation of ecosystems over time. Surface waters not only suffer from external point sources emitting nutrients and pollutants, but also from a variety of other anthropogenic impacts. These influences comprise diffuse losses into aquatic ecosystems especially from agriculture and from the atmosphere, and severe damage of the surface water structure by construction work, excessive use, spatially extended decreases in groundwater level, and leaks of petrol components in catchments. At present, diffuse loading are increasing rather than decreasing, and result from both former and present land use in catchments. The diffuse losses cause problems for the protection of standing and running waters as well as for estuaries and ocean via long-distance influences. However, the »emission principle« has started to counteract the negative developments of external loading, and refers to both point sources from communal and industrial waste water treatments, and diffuse losses especially due to agricultural activities. Nonetheless, the present external loading is still about 10-fold higher than the geogenic background. In addition, long residence times in groundwater delay the effects of reduced emissions on 110 diffuse loading for several decades. The application of emission-oriented measures alone for the improvement of water quality has limited success. Internal mechanisms may counteract a rapid and efficient improvement of water quality, for example by nutrient and pollutant release from sediments, alterations of the food web, and long residence times of the water bodies (Hupfer & Kleeberg 2007). The nitrogen elimination in waste water treatments exemplifies that in some cases, emission-oriented measures are often not useful from the economic and ecological point of view. First, nitrogen loading can efficiently be eliminated in the water body by natural microbial nitrate reduction especially in combined lake-river systems, and second, the decrease of nitrate emissions promotes phosphate mobilisation from sediments. Thus, the measure is counterbalanced. For these reasons, highly efficient measures for surface water protection require complex and integrated actions (Figure 1). Improvements and stabilisation of aquatic ecosystems by reduction of point and diffuse loading (redevelopment), must be balanced with structural optimisation of ecosystems (restoration and ecotechnology in surface waters and catchments). This combined strategy will be elucidated by exemplifying important problems and trends of the water quality of standing and running waters in Germany. RECREATION outstanding restricted good very low polluted catchment area (high evectiveness of landscape) unpolluted natural oligotrophic to slightly eutrophic aquatic ecosystems WATER QUALITY poor problem-free degrated highly eutrophic aquatic ecosystems problematic DRINKING WATER, BATHING, FISHING highly polluted catchment area (slow evectiveness of landscape) Fig. 1: The influence of the terrestrial surroundings on water use and water quality (Koschel et al. 1998). 3.4.2.2 Pollutant exposure in rivers, lakes, and coastal waters Aquatic ecosystems are prone to numerous natural and anthropogenic stress factors of a physical, chemical, and biologic nature, resulting from loading of energy, waste waters, and bacteria. The most common problems in surface waters, causing significant restrictions of their use, are loadings of nutrients and pollutants. Pollutant loading can be evoked by a broad spectrum of inorganic and organic chemicals. Anthropogenic sources of toxic metals comprise ore processing, metal industry, road traffic in urban centres, the use © IGB 2007 111 of herbicides, and emissions of gases rich in sulphur and nitrogen, the latter of which lead to corrosion of metal surfaces. Organic pollutants consist of pesticides, organic tensides, pharmaceutical chemicals, and petrol components. Metals and organic chemicals, such as polychlorinated biphenyls (PCB), become enriched in sediments and food webs, and may exceed toxic concentrations. Chemicals that act as pseudohormones, and influence the reproduction and development of vertebrates, are released in high concentrations in urban areas; these substances are defined as hormone-active substances or endocrine disruptors. Synthetic-active substances are part of pharmaceuticals and industrial chemicals (e. g. organo-chlor-pesticides, PCB, derivates of tensides, and phtalates). For example, synthetic estrogens, which are part of contraceptives and other hormone treatments, are released into the environment via waste water and waste water treatments. The emissions of gases containing sulphur and nitrogen cause acid rain, which in turn promotes acidification of surface waters and soils in regions with low chalk and low buffering capacity. This happens even at great distances from the points of emissions. Acidified surface waters are often clear and thus, apparently are of high water quality. However, the decrease in pH is a reason for the extreme changes of their biocoenoses. Fish and other animals cannot survive or reproduce. As a further consequence, toxic metal ions (especially aluminium, copper, zinc, and lead) are increasingly released from soils and sediments. Especially the north-east of North America and Scandinavia are suffering from acidification. In Germany, the acidification via atmospheric deposition is limited to some regions, such as in the Bavarian Forest and the Black Forest. In addition, exploitation of natural resources can render surface waters prone to extreme acidification. In Germany, there are approximately 500 lakes created by coal mining on a medium-term scale of 10 to 50 years. Most of these lakes are geogenically strongly acidified during their generation. Coal mining leads to the oxidation of minerals rich in sulphur (pyrite, marcasite) causing the release of acids. 3.4.2.3 Eutrophication Eutrophication is the most common problem in surface waters. Eutrophication is defined as the increasing intensity of primary production (trophic state) of a surface water, which is due to increased availability and uptake of nutrients. Since the middle of the last century, the extent of eutrophication has been markedly increased by insufficiently treated waste water, artificial use of nutrients in households (phosphorus in detergents), and by run-off from agricultural areas. Thereby, the deterioration of lakes has been significantly accelerated. As a consequence of eutrophication, blooms of phytoplankton and macrophytes have undesired impacts and severely restrict water uses. The water becomes turbid and changes its colour, blooms of toxic cyanobacteria, loss of diversity, oxygen depletion, generation of sulphide, high fish mortality, and nuisance by smell occur. Thereby, several types of water uses, such as water supply, fishing, and recreation become restricted. Additionally, in eutrophicated surface waters, 112 the effects of toxins can be synergistically reinforced, because these ecosystems are partly destabilised. In Germany, there are significant regional differences in the trophic state of lakes. In Brandenburg and Mecklenburg-Vorpommern, 90% of 1,500 lakes were classified as mesotrophic or eutrophic, whereas in Bavaria and Baden-Württemberg, less than 50% were of high trophic state. The reasons for this difference are partly natural. The present and former loadings from agriculture are reflected by a high portion of eutrophicated lakes. A major problem due to eutrophication of inland waters results from the proximity of intensely used agricultural areas to surface waters, and the intensification of this, coupled with drainage and irrigation measures. Agriculture targets at maximum plant production, however, high biomass production in surface waters should be avoided because of its negative consequences. The phosphorus (P) acts as a limiting factor and controls the degree of eutrophication in most inland waters. Since the mid 1980s, the existing dominant point emissions of P, were reduced by as much as 80% with the introduction of P-free detergents. However, the diffuse emissions of P were only slightly decreased. Small losses of P from the terrestrial catchment usually mean a considerable charge of water ecosystems by P. For many inland waters, loadings related to events such as rainfall the result in shortterm erosion. The slow P export via leaching, is a long-term problem difficult to predict. At sites with a low sorption capacity near the groundwater table, the long-term fertilisation of agricultural areas, especially by manure, may cause complete saturation with P in the entire soil layer. Scoumans et al. (1988) found that already at the end of the 1980’s, more than 10,000 ha of soils were saturated with P in the Netherlands. Similar phenomena can be found also in other regions with low groundwater tables, soils with low sorption capacity and extreme livestock densities (Behrendt & Beockhold 1993). Also in rivers in the north-west of Germany, those catchments which drain agriculturally farmed peat soils with extreme low sorption capacity are very vulnerable to P leaching. The consequence of both cases is that P-concentrations in small rivers can reach the order of magnitude of municipal waste water. Many running waters are suffering from eutrophication. For example, during the last decades, a considerable increase in algal biomasses could be detected in the low courses of the large German rivers. This was due to waste water treatment strategies which primarily aimed to reduce organic loadings, and neglected the elimination of mineral nutrients; thereby, nutrients were emitted directly in available forms to surface waters (Behrendt et al. 2003). Eutrophication sources of shallow coastal waters, such as lagoons, show that the sources of eutrophication can be several 100 kilometres distant from the location where the eutrophication occurs. For example, the River Oder contributes 15% of the total nutrient emissions to the Baltic Sea, yet it forms a low portion (7%) of the catchment of the Baltic Sea, it has however a high population density which contributes to the sources of eutrophication (Behrendt & Dannowski 2005). © IGB 2007 113 The change in nutrient loads of rivers could be reconstructed by the modelling of emissions to, and the turnover within, surface waters, including periods without measurements. Figure 2 represents the changes of P loads in the River Oder during the last 50 years. Although a decrease in P load due to the introduction of P-free detergents has already started, the present level of P loading to the Baltic Sea by the River Oder exceeds the emissions in the 1960’s. 7000 6000 phosphorus load (t/a) 5000 4000 3000 2000 1000 0 1960 1965 1970 1975 1980 1985 1990 1995 2000 Fig. 2: Phosphorus loads of River Oder to the Baltic Sea (1960-2000) (Behrendt & Dannowski 2003). 3.4.2.4 Strategies to control water ecosystems Problems with surface waters are usually first perceived when there are restrictions in water uses. Remedial actions aim to improve the state of surface waters, while keeping costs reasonably low. Concerning the planning and execution of measures, the practical question arises as to the degree to which the development of the problem should be reversed. The aim of the remediation is often the return to the natural or original state. However, definition of this state is difficult. It should not mean the state directly after generation of the surface water. What should be defined as the original state? When humans did not yet decisively influence the ecosystem, which usually means before the Neolithicum, at the end of the Atlanticum, approximately 5,000 years ago? In those times, climate was warmer than today, and in Central Europe, the catchments of the inland waters were covered by a dense canopy of mixed oak tree forests (oak tree, lime tree, elm tree). It is impossible to redevelop the climate of a landscape and its surface waters, and it is almost impossible to change the cultivated landscape of today into a non-cultivated forest landscape. Therefore, the maximum aim of natural remediation measures should be the potential natural state of surface waters. This reference state, the named ideal state, is characterised by a state, which is close to that of preindustrial times. The ideal state can be individually estimated for each water body by guidelines and by palaeolimnological investigations, and is to be compared with the actual state. The need for action is great if the actual state significantly differs from the ideal state. In contrast, the formulation of the aim of development for a lake or river is arbitrary, but should be adapted to present and future human exploitation and settling of the landscape, to ecological knowledge, technical progress and 114 financial capacities (Steinberg et al. 2002). The definition of the aim of development is an iterative process that should be carried out in concert by users, owners, experts, and politicians. The charge limits of a water ecosystem are determined by its structure and the structure of its environment. For example, the potential decomposition of organic substances is much lower in regulated river systems than in naturally structured water courses. Critical load models are helpful for achieving qualitative aims of aquatic ecosystem management. These models enable the user to describe qualitative states of an ecosystem, depending on the charge and characteristics of the surface waters. This means that a potential control strategy may include the optimisation of the structure and processes within a lake, so that symptoms of excessive charge can be minimised. The response to changes of charges often follows a sort of hysteresis, in which eutrophicated lakes can persist in their state, despite reductions of external loadings. Furthermore, sufficient decreases in external loadings cannot always be achieved at suitable low costs, and remaining loadings can be compensated for by internal measures. Modern protection of surface waters should therefore consider a combination of external and internal measures. Which external and internal methods and control opportunities are available at present? There are many examples for a slow reduction of diffuse nutrient emissions by »best management practice« and by extensifying agricultural land use. 3.4.2.5 Optimisation of sinks and ecotechnology Beside the reduction of nutrient emissions at their source, the restoration of original nutrient retentions structures within the landscape, such as bogs, ponds, and floodplains, represents the opportunity to reduce diffuse nutrient emissions by internal links in terrestrial and aquatic ecosystems. Thereby, a sustainable management of matter and water circulation is accomplished. Intact ecosystems minimise losses of matter by short-circuiting cycles of water, nutrients, and mineral substances (Ripl & Wolter 2001). Intact ecosystems are sustainable. However, the consequent application of the concept mentioned above would result in severe restrictions, or even losses, of existing uses. External loading can and must also be reduced close to surface waters by the construction of phosphorus elimination plant for the purification of river water, or by the creation of buffer systems, such as barriers and retention areas planted with Phragmites australis, if it is not possible to create retention structures within the catchment. Technical procedures can influence the physical, chemical, and biological structure of surface waters. Reduction of available nutrients can be used to reduce primary production within the water body, and hence improve its trophic state. The desired improvement can be accelerated, and at the same time external loadings can be decreased, if the P retention within the sediments of lakes is increased by the use of substances for chemical precipitation. Thereby, remaining loading could be compensated for or a level of P concentration could be attained which allows positive feedback and the efficient application of further measures. Biomanipulation is a © IGB 2007 115 reasonable example for such measures. By biomanipulation, fish populations are optimised. As a consequence of the resulting decline of the food web, feeding pressure on undesired phytoplankton is increased, and the water becomes clearer. However, global evaluation of such applications has revealed that a certain level of P loading has to be accomplished in order to achieve efficient biomanipulation. In conclusion, high efficiency of measures in surface waters can be achieved by a combination of measures. 3.4.2.6 Need for action and research - Using the ecological potential Recent investigations showed that restoration measures oriented only towards the reduction of emissions is questionable, especially considering the limited financial resources in water protection. The vision that any loading reduction has always a positive effects is no longer valid. Instead, the capacities of ecosystems to withstand charges dependent upon their structures has to be explored, and the manifold ecological functions and services have to be used optimally. At present, detailed knowledge of the functioning of surface water ecosystems and their reactions to anthropogenic influences is insufficient. In particular, our understanding is lacking considering that the state of aquatic ecosystems is a function of biological, chemical, hydraulic, hydrological, meteorological, and physical influencing factors, including their temporal and spatial changes. There is a need for an efficient and integrated scientific instrument, which will enable us to analyse the behaviour of ecosystems on a functional, process-oriented, and reproducible basis. In addition, the trends in development of ecosystems need to be calculable with a high degree of certainty (Figure 3). character of ecosystems energy - and matter limitation open dissipative systems reflection in theory of management M minimize energy waste close matter circulation sensitive reaction to external inputs (e.g. climate change) homoeostatic systems multiple mediated feedback systems unexpected consequences (e.g. toxical cyanobacteria) adaptive, self-organizing systems ways of self-adaptation (e.g. bistability) Fig. 3: Theoretical principles of aquatic ecosystems, their reflection in the theory of aquatic ecosystem management and the illustration of knowledge deficits (modified after Straskraba 1993). The comprehensive and harmonised integration of applied external measures (within the catchment), and internal measures (within the water ecosystem), should be increasingly efficient, if the existing lack of knowledge is minimised. Both the principles of emissions and imissions have to be considered within integrated surface water protection. 116 - Acceleration of knowledge transfer in the water economy Lewandowski et al. (2002) have revealed that the actual effects of lakeinternal measures were often far below those expected. In some instances the applied scientific measures were useless. The research task should be to improve and evaluate the scientific basis of lake-internal measures. In turn, this knowledge should feed applicable decision support systems (Schauser et al. 2003). The better the scientific basis, the more difficult it is to ignore the state of the art (Figure 4). The slow publication of research results limits knowledge transfer, and our knowledge of the environment needs to be more publicly accessible. Analysis of current state Check-up of targets Identification of problems and definition of targets for the water qualitity Determination of acceptable nutrient loading by using of lake models Identification and quantification of external and internal nutrient sources Yes Are measures in the catchment area planned or already carried out? Yes Prediction Can the external loading decrease below a critical threshold within tolerable periods? No No Yes Is the expected adaptation time after external measures acceptable? No Cause study Long water residence time? High internal loading? No Yes Yes Yes Yes Internal measures may be possible No No Yes Internal measures are inefficient Fig. 4: Decision making process prior to the application of ecotechnologies, demonstrating procedures fpr increasing nutrient retention in a lake (Hupfer et al. 1997). - Strengthening our knowledge base by case studies Further reduction of emissions from point sources does not lead to a remarkable decrease of external nutrient loading with acceptable costs. It seems that mainly diffuse loading is an unsolved long-term problem, difficult to identify, and to predict by existing methods. Case studies from diverse geographical regions could help to analyse the effects, and the course of nutrient loading, by changing land use. Little knowledge exists on the locations and capacities of retention mechanisms in © IGB 2007 117 relation to the total loading from catchment areas. For example, the risk of rewetting bogs, which thereby might become P sources, is controversial, because bog systems apparently react in different ways. Restoration of P retention areas may lead to a restriction or decline of existing human uses, which however, decreases public acceptance. The socio-economic problems related to these consequences also have to be solved by related scientific approaches. Holistic pilot studies could contribute to solving these problems (»whole ecosystem experiments« as scientific method). - Development of cost benefits analysis There are great gaps in our knowledge of the economic evaluation of ecological functions of surface water systems. In addition, by practical applications it was shown that even sound scientifically-based management measures are not always accepted and financially supported. Therefore, there is a need for further supporting arguments. The inclusion of financial efficiency should be considered as an important element of future strategies for surface water protection. However, the scientific basis is incomplete. These requirements become increasingly important, especially concerning the implementation of the Water Framework Directive of the EU (WFD), which aims to accomplish and evaluate a »good ecological state« for all surface waters. - Policy recommendations and reinforcement of basic research Conversion of integrated protection of surface waters and the sustainable development of the environment entails many new tasks and challenges for surface water research. Therefore, we need scientifically well based and defined ideals, which are oriented towards the main ecological and hydrological functions of surface waters. The main function can be defined as, the complexity of the food web extending from bacteria to fish (information is stored in structures and genetic codes), the discharge rate of water bodies, the matter circulation, the self-purification potential and the close interrelationship between air (climate), land, and water. We need highly developed instruments (models) for determining and predicting the integrative impacts of anthropogenic and natural factors on the quality and quantity of surface water ecosystems, which in turn should include both socio-economic and global climate changes. We need an extended basis for the economic evaluation of water as a resource. Modern integrated protection of surface waters requires an efficient combination of the principles of reconstruction, redevelopment, restoration, and ecologically useful and sustainable water use. In advance, these requirements demand a high degree of knowledge of the manifold and highly complex processes in surface water ecosystems. Equally, there is a high need for basic research, which should cover improved knowledge of biological, chemical, and physical structures and their functions within surface water ecosystems, and of the regulation of the manifold transport and transformation processes extending from the catchment to the water bodies. 118 - Increase social acceptance Integral surface water protection inevitably causes conflicts between inhabitants, users of water and land, and owners. These conflicts can only be solved on a long-term basis if environmental education is reinforced, and new forms of public discussion are developed. There have to be opportu¬nities created for politicians, employees of districts and communities, and pressure groups to gain knowledge about the field of surface water protection. Dissemination of information to the media can contribute to making water problems perceivable and to highlight possible actions. Conflicts should increasingly be solved in panels with the participation of inhabitants and the public in the decision process. Public interest and political pressure have sometimes meant that internal measures in polluted lakes were carried out without the necessary preliminary investigations. Often, these measures were not successful, and at the same time, they exploited the scarce financial resources, which could have been used for more efficient measures. - Combine the principles of emissions and imissions Surface waters are closely connected to their terrestrial environment, and therefore, preventive protection of surface waters begins in the catchment. Limited financial resources for surface water protection demand an optimal combination of the principles of emissions and imissions (Benndorf et al. 2003). Many ecological and technical standards are oriented towards the principle of zero emissions (such as those for toxic substances), the state of the art of technology (for example four purification steps in waste water treatments), or they are apparently arbitrary. In some cases, imissions of nontoxic substances could be tolerated, which are higher than the concentrations permitted by directives and laws, if the ecosystem structure is created and optimised accordingly. The latter can be accomplished by eco-technological procedures. Therefore, the principle of zero emissions of any costs is not recommended. Efficient protection of surface waters requires procedures which are adapted to individual cases and regions. References BENNDORF, J., KOBUS, H., ROTH, K., SCHMITZ, G. (eds.) (2003): In: DEUTSCHE FORSCHUNGSGEMEINSCHAFT: Wasserforschung im Spannungsfeld zwischen Gegenwartsbewältigung und Zukunftssicherung (Water research in the discourse of overcoming present problems and future security.), Wiley, Weinheim, 175 pp. BEHRENDT, H., BOEKHOLD, A. (1993): Phosphorus saturation in soils and groundwater. Land Degradation & Rehabilitation, 4, 233-243. BEHRENDT, H., BACH, M., KUNKEL, R., OPITZ, D., PAGENKOPF, W.-G., SCHOLZ, G., WENDLAND, F. (2003): Quantifizierung der Nährstoffeinträge der Flussgebiete Deutschlands auf der Grundlage eines harmonisierten Vorgehens. (Quantification of nutrient emissions in the catchments of Germany using harmonized procedures.) Text of the UBA, 82/03, 201 pp. BEHRENDT, H., DANNOWSKI, R. (eds.) (2003): Nutrients and heavy metals in the Odra River system, Weißensee Verlag, Berlin, 335 pp. © IGB 2007 119 CONSTANZA, R., D‘ARGE, R., DE GROOT, R., FARBER, ST., GRASSO, M., HANNON, B., LIMBURG, K., NAEEM, S., O’NEIL, R. V., PARUELO, J., RASKIN, R. G., SUTTON, P., VAN DEN Belt, M. (1997): The value of the world’s ecosystem services and natural capital. Nature, 387, 253-260. HUPFER, M., GELBRECHT, J., SCHARF, B. & C. STEINBERG (1997): Konzeptionelle Ansätze zur Steuerung des Phosphat-Haushaltes durch seeinterne Maßnahmen. (Conceptual approaches to control the phosphorus budgets by lake-internal measures.) Wasser und Boden, 49 (12), 8-13. HUPFER, M., KLEEBERG, A. (2007): State and pollution of freshwater ecosystems – warning signals of a changing environment. In: LOZAN, J. L., GRAßL, H., HUPFER, P., MENZEL, L., SCHÖNWIESE, D. (eds): Global change: Enough water for all? Hamburg, 126-132. KOSCHEL, R., BRÜGGEMANN, R., KASPRZAK, P. (1998): Ökotechnologien zur Sanierung und Restaurierung von Standgewässern. (Ecotechnologies to reconstruct and restore standing waters.) Spektrum der Wissenschaften, 9, 97-100. KOSCHEL, R., BEHRENDT, H., HUPFER, M. (2005): Integrierter Gewässerschutz für Binnengewässer: Maßnahmen zum nachhaltigen Umgang mit der Ressource Wasser. (Integrated protection of surface waters for the sustainable use of the resource water.) In: WGL (eds.): Zwischenruf, 2, 4-15. KOSCHEL, R., BEHRENDT, H, HUPFER, M. (2007): Surface waters under stress factors and their controlling by integrated measures. In: LOZAN, J. L., GRAßL, H., HUPFER, P., MENZEL, L., SCHÖNWIESE, D. (eds): Global change: Enough water for all? Hamburg, 89-94. LEWANDOWSKI, J., SCHAUSER, I., HUPFER, M. (2002): Bedeutung von Vor- und Nachuntersuchungen in der Seentherapie. (The importance of pre- and postinvestigations in lake therapy.) Wasser & Boden, 54 (9), 21-25. RIPL, W., WOLTER, K.-D. (2001): Stoffstrommanagement nach dem EnergieTransport-Reaktions-Modell (ETR-Modell) (Management of substance flow according to the energy-transport-reactions-model). Wasser & Boden, 53(10), 4-9. SCHAUSER, I., LEWANDOWSKI, J., HUPFER, M. (2003): Decision support for the selection of an appropriate in-lake measure to influence the phosphorus retention in sediments. Wat. Res., 37, 801-812. STEINBERG, C., WEIGERT, B., MÖLLER, K., JEKEL M. (eds.) (2002): Nachhaltige Wasserwirtschaft. Entwicklung eines Bewertungs- und Prüfsystems (Sustainable water economy. Development of a system for evaluating and testing.). Initiativen zum Umweltschutz, 36, Schmidt Verlag Berlin, 311. pp. STRASKRABA, M. (1993): Ecotechnology as a new means for environmental mangement. Ecol. Engineering, 2, 311-331. WISSENSCHAFTLICHER BEIRAT DER BUNDESREGIERUNG GLOBALE UMWELTVERÄNDERUNGEN (WBGU) (1999): Welt im Wandel – Erhaltung und nachhaltige Nutzung der Biosphäre. Jahresgutachten 1999. (Global change – conservation and sustainable use of the Biosphere.). Annual Report, Springer, Berlin 482 pp. 120 M EINELT , T., B URNISON , B. K., P LAYLE =, R., P IETROCK , M., W IENKE , A., S TEINBERG , C. E. W. 3.4.3 Dissolved organic matter (DOM) modulates the cadmium accumulation in zebrafish (Danio rerio) embryos Huminstoffe beeinflussen die Cadmium-Akkumulation in Zebrabärblingsembryonen (Danio rerio) Key words: cadmium, accumulation, DOM, egg compartments, zebrafish Abstract We conducted experiments to investigate factors influencing the accumulation of cadmium 109Cd into zebrafish (Danio rerio) embryos. The Cd accumulation was affected by 1) concentration, 2) time, 3) presence of dissolved organic material (DOM), 4) different origin of DOM and 5) different parts of fish eggs. The zebrafish eggs showed a steady increase in Cd-accumulation with time and concentration. DOM concentrations over 15 ppm carbon (C) decreased Cd uptake significantly. Both DOM-samples, the brown water marsh (LM) and an eutrophic pond (SP), at 16.9 ppm C, reduced the Cd-accumulation in the chorion, perivitelline liquid and the embryo. Cd was mainly accumulated in the egg’s outer shell chorion (61%) and only small amounts passed through the chorion into the perivitelline liquid (38%) and embryo (1%). The accumulation of Cd into the egg components was decreased by 41% (chorion), 56% (perivitelline liquid) and 53% (embryo), in the presence of LM-DOM, compared with the control group. Similarly, the presence of SP-DOM reduced the Cd accumulation by 27% (chorion), 63% (perivitelline liquid) and 59% (embryo), respectively, compared with the controls. Zusammenfassung Mittels radioaktiv markiertem Cadmium 109Cd wurden Faktoren untersucht, welche die Cd-Akkumulation modifizieren. Die von uns untersuchten Parameter waren 1) Cd-Konzentration im umgebenden Testwasser, 2) Expositionszeit, 3) Präsenz und Konzentration (in ppm Kohlenstoff) von Huminstoffen (HS), 4) Herkunft der HS und 5) verschiedene Fischeikompartimente. Die Zebrafischeier zeigten eine mit der CdKonzentration und Expositionszeit stetig steigende Cd-Akkumulation. HSKonzentrationen >15 ppm Kohlenstoff verringerten die Cd-Akkumulation signifikant. Die Präsenz beider verwendeten HS, Luther Marsh (LM) und Sanctuary Pond (SP), in Konzentrationen von 16,9 ppm Kohlenstoff reduzierten die Cd-Akkumulation im Chorion, in der Perivitellinen Flüssigkeit und im Embryo. Cd wurde hauptsächlich im Chorion (61%) akkumuliert. Nur kleinere Cd-Mengen passierten diese Barriere und akkumulierten sich in der Perivitellinen Flüssigkeit (38%) bzw. im Embryo (1%). Die Cd-Akkumulation in den einzelnen Kompartimenten der © IGB 2007 121 Zebrabärblingseier wurde durch LM-HS um 41% (Chorion), 56% (Perivitelline Flüssigkeit) bzw. 53% (Embryo) reduziert. Bei SP-HSExposition verringerte sich die Cd-Akkumulation um 27% (Chorion), 63% (Perivitelline Flüssigkeit) bzw. 59% (Embryo) verglichen mit der Kontrolle. 3.4.3.1 Introduction Both the uptake of Cd and its toxicity to fish have been intensively studied (John et al. 1987), and are known to be affected by several water parameters, particularly the concentrations of calcium (Ca2+, Michibata et al. 1986) and dissolved organic matter (DOM, Playle 1998, Playle et al. 1993a, 1993b, Richards et al. 1999). The amount of metal which can be complexed to DOM depends on pH, ionic strength, metal concentration and some DOM characteristics (Petersen et al. 1987). A number of studies have shown that DOM can either increase or decrease the toxicity of metals to freshwater organisms (Playle et al. 1993a, Penttinen et al. 1995, Richards et al. 1999, Meinelt et al. 2001). Hammock et al. (2003) studying the accumulation of different metals in Chinook salmon (Oncorhynchus tshawytscha) eggs noted e. g. reduced Cd-concentrations in the egg chorion and yolk in the presence of a humic acid (Aldrich®) compared to control. According to Michibata (1981) and Beattie & Pascoe (1978), most of the total Cd detectable in eggs of medaka (Oryzias latipes) and trout (Oncorhynchus mykiss), is bound to the chorion. The present study we tested the effects of exposure time, and metal and DOM concentration on uptake and quantitative distribution of 109Cd in the presence of two different DOM. 3.4.3.2 Material and Methods Rearing of the parental fish, production of eggs, test water Production of eggs and rearing of embryos is described in Meinelt et al. (2001). The investigations were carried out using standardized test water according to EN ISO 7346-3 (1996). To minimize Ca2+ interference, the calcium content of the water was reduced to a tenth of the nominal reconstituted water-Ca concentration. Thus the reconstituted water contained Ca2+ 0.2 mmol L-1, Mg2+ 0.5 mmol L-1, K+ 0.077 mmol L-1, Na+ 0.77 mmol L-1; dissolved oxygen was 7.0 ± 0.5 mg L-1, pH between 7.47 – 7.97, and temperature 22 ± 0.2°C. Dissolved organic matter (DOM) DOM was isolated from two natural waters of different trophic states and with different DOC concentrations as described by Burnison et al. (2006). Luther Marsh (LM) yielded mainly allochthonous DOM and Sanctuary Pond (SP) mainly autochthonous DOM. Exposure time experiment To examine the effect of exposure time on accumulation of 109Cd in zebrafish eggs, ten fertilized eggs were transferred into a 1.5 mL microcentrifuge tube with cap containing 350 µL reconstituted water containing 109Cd (Amersham Biosciences, specific activity = 41.6 MBq/µg) with a radioactivity of 3000 kBq. After exposure times of 15, 30, 45, 60, 120, 180, 240, and 300 minutes, respectively, an excessive amount of “cold” Cd 122 (as CdCl2 x H2O, 500 ng) was added to each tube to block free binding sites at the chorion and, thus, limiting further uptake of 109Cd. After rinsing the eggs with reconstituted water, the eggs were transferred to glass scintillation vials, and 10 mL of scintillation cocktail (Ultima Gold, Packard Instrument Co.) were added. The radioactivity of the eggs was determined using a liquid scintillation counter (Tri-Carb 4430, Packard Instrument Co.) The exposures were run in duplicate. Metal concentration experiment To examine the effect of metal concentration on accumulation of 109Cd, ten fertilized eggs were placed into Petri dishes (Falcon Tight-Fit Lid, 50 mm, Fisher Scientific) containing 2 mL of reconstituted water with one of four different 109Cd concentrations. The 109Cd concentrations were calculated on the basis of the radioactivity present in each solution, and the specific activity of the radioisotope. The duplicate Cd-concentrations were 7.02/7.03, 14.0/13.8, 33.2/33.7, and 63.7/64.0 nM. After an exposure time of four hours, “cold” Cd was added to each solution, followed by rinsing the eggs with reconstituted water, addition of the scintillation cocktail and determination of radioactivity (see above). DOM concentration experiment Twenty fertilized eggs were placed into a Petri dish and exposed to 20.3 nM 109Cd mixed in 6 mL of either reconstituted water containing no added carbon (control), or with 5, 10, 15, 20 ppm C, LM DOM. After 8 hours exposure, the eggs of each group were rinsed three times with reconstituted water to remove free 109Cd, and 10 mL of the scintillation cocktail (Ultima Gold, Packard Instrument Co.) were added to the eggs to determine their radioactivity using the liquid scintillation counter (see above). The experiment was run in triplicate. Dissection experiments Twenty fertilized eggs each containing a 24-hour-old embryo were placed into a Petri dish and exposed to two ml Cd solution (20.3 nM 109Cd) mixed with six ml of either reconstituted water containing no added carbon (control), 16.9 ppm C of LM- or 16.9 ppm C of SP-DOM. After a four-hour exposure, the eggs of each group were rinsed three times with reconstituted water to remove free 109Cd, and then transferred into Petri dishes containing 3 mL of reconstituted water. An aliquot (100 µL) was transferred from each of the three dishes into separate scintillation vials and measured for radioactivity to ensure that no free 109Cd remained. The intact eggs were carefully dissected into their components (chorion, embryo, perivitelline liquid [Fig. 1]) by means of a stereomicroscope and two sharpened microforceps. The thin chorion shells were transferred into 1.5 mL microtubes and were centrifuged at 2,800 rpm. The supernatant was carefully returned into the respective Petri dish that still contained the embryos. The chorion pellets were washed three times again and transferred into scintillation vials. Embryos were pipetted into scintillation vials by means of wide bore Eppendorf tips to protect the fragile embryos from mechanical © IGB 2007 123 damage. Any fluid carried over along with the embryos was carefully put back into the Petri dish using a micropipette. Finally, this fluid, consisting of perivitelline liquid and reconstituted water washes, was transferred into Chorion Perivitelline Embryo 250 µm Fig. 1: Microscopic structure of zebrafish egg separate scintillation vials. Ten mL of the scintillation cocktail were added each to chorion-pellets, embryos and perivitelline liquid/reconstituted water preparations and radioactivity was measured using the liquid scintillation counter (see above). The experiment was run in triplicate. Statistical analysis Statistical analysis was conducted by using of SPSS 9.0.1 (SPSS Inc. 1999) using standard procedures. Analyses of variance (ANOVA) were used for the dissection experiments, the unpaired t-test were used to analyze the data of the DOM experiments. Significance level was set at p= 0.05. The statistical methods used are outlined in Lozan & Kausch (2004). 3.4.3.3 Results and Discussion With increasing exposure time, the total amount of 109Cd in the eggs increased (Fig. 2). A positive correlation between exposure time and amount of 109Cd taken up by the zebrafish eggs was found (r= 0.82). In the concentration experiments, a positive correlation between metal concentration in the test medium and amount of 109Cd taken up by the zebrafish eggs was found (r = 0.92, Fig. 3). With increasing concentrations of DOM (LM) from 10 - 20 mg L-1 C there was a significant reduction in Cd accumulation in the fish eggs compared to the control (Fig. 4). Exposure to both LM-DOM as well as SP-DOM at concentrations of 16.9 mg L-1 C led to a significantly (p < 0.01) reduced amount of Cd detectable in the eggs (Fig. 5). However, no significant difference between LM- and SP-DOM (p= 0.813) was detected. In the presence of LM-DOM, the accumulation of Cd into the zebrafish egg decreased by 41% in the chorion, 56% in the perivitelline liquid and 53% in the embryo, compared with control group eggs. Similarly, in the presence of SP-DOM, Cd accumulation decreased by 27% (chorion), 63% (perivitelline liquid) and 59% (embryo), compared with the controls (Fig. 6). Cd accumulation in perivitelline liquid was significant lower in DOM-groups compaired to the controls (p< 0.0001), wheras there were no significant differences in Cd accumulation in embryo and chorion compaired to 124 controls (p= 0.487, p= 0.159). The Cd content of zebrafish eggs increased significantly with time and Cd concentration of the surrounding medium. We Cadmium Uptake (picomol/g) 50 40 2 R = 0.66 30 20 10 0 0 50 100 150 200 250 300 Time (min) Fig. 2: Time dependent cadmium uptake by zebrafish eggs 160 Cadmium Uptake (picomol/g/hr) 140 120 2 R = 0.93 100 80 60 40 20 0 0 10 20 30 40 50 60 70 Cadmium Concentration (nM) Fig. 3: Concentration dependent cadmium uptake by zebrafish eggs found a steady increase in Cd accumulation over 300 minutes. In Atlantic salmon (Salmo salar), Rombough & Garside (1982) found a rapid Cd uptake by embryos, with dose-dependent saturation levels which were reached within 24 h and persisted until hatching. Thus the time point of reaching saturation depends strongly on external factors. Species-specific endogenous factors may also affect Cd uptake in fish eggs (see below). When Cd is © IGB 2007 125 accumulated in fish eggs, it may be detected in the different components at different concentrations. Typically most of the Cd is associated with the chorion (Peterson & Martin-Robichaud 1986), which in rainbow trout (Oncorhynchus mykiss) keeps 98% of the total Cd, (Beattie & Pascoe 1978), in medaka (Oryzias latipes) 94.6% (Michibata 1981) and Chinook salmon (Oncorhynchus tshawytscha) 93% (Hammock et al. 2003). In our experiments we found that only 61% of the Cd was bound to the chorion of the zebrafish eggs. Cadmium Uptake (picomol/g/h) 250 200 * * 15 20 150 100 50 0 Control 5 10 DOC (mg/L) Fig. 4: Influence of different concentrations of Luther Marsh DOM on Cd-accumulation in zebrafish eggs. Error bars represent standard deviation (n = 3) and the asterisks denote a significant difference compared to the control at the p < 0.05 level. Fish species may be a major reason for the variation in Cd retention by the chorion, because the thickness of the chorion varies widely among species. Chinook salmon eggs are up to 10 mm in diameter and show a chorion thickness of up to 50 µm. In contrast, diameter of the zebrafish eggs is about 1 mm with a chorion thickness of about 3.5 µm, which is thus more than 14 times thinner than the Chinook salmon egg chorion. Calculating the volume of the Chinook salmon egg, their chorion comprises a 1,400 times higher volume compared to the zebrafish chorion. According to Rombough (1985) the chorion potentially modulates the toxicities of metals since metal ions must penetrate the chorion, before they exert toxic effects on the embryo. Since the chorion is rich in negatively charged glutamic acid, metal cations probably bind selectively to such anionic sites (Rombough 1985). In this respect, thick eggs like that of salmon contain high amounts of glutamic acid which has a much higher retention capacity for Cd than do thin 126 zebrafish eggs, with presumably low amounts of glutamic acid, and hence a lower retention capacity for Cd. In the presence of DOM, the accumulation of Cd in the zebrafish eggs was significantly lower than the control, 53% for LM and 58% for SP, respectively. The reduction in Cd accumulation is also reflected by a specifically lowered Cd content in the different egg components. If DOM was present, the allocation of Cd in the chorion declined to 41% (LM) and 26% (SP), compared to the control, in perivitelline liquid 56% (LM) and 63% (SP) compared the controls, while in the embryo only 53% (LM) and 59% (SP) compared to DOM-free control remained. We hypothesize that formed DOM-Cd complexes were unable to penetrate the chorion thus binding to its surface. Therefore, the amount of Cd, capable of penetrating the egg chorion is lowered in presence of DOM. Cadmium Upake (pmol/g/h) 1200 1000 800 * * Luther Marsh Sanctuary Pond 600 400 200 0 Control Fig. 5: Effect of different DOM sources (16.9 mg L -1 C) on Cd-accumulation in zebrafish eggs. Error bars represent standard deviation (n= 3) and the asterisk denotes a significant difference compared to the control at the p< 0.05 level. Both DOM sources lowered the amount of Cd accumulated in egg components compared to control. However, only Cd-accumulation in perivitelline liquid was highly significant different between DOM-groups and controls. Although the two water bodies from which the respective DOM were isolated differ in total content, origin and formation of their DOM, the capacity to prevent passage of Cd through the chorion of zebrafish eggs was very similar. Several recent ecotoxicological studies have consistently identified that watersoluble and ionizable humic materials are relatively small (~0.5 kDa) and, when considering a single source, are very regular in structure (Reemtsma & These 2003, Cooper et al. 2004, Hatcher et al. 2004, Seitzinger et al. 2005). Additionally, these authors consistently state that, if higher molecular masses than ~0.5 kDa do occur, the building blocks are © IGB 2007 127 bridged by several intramolecular mechanisms, whereby one major mechanism is the bridging of two- or polyvalent cations, such as Cd2+ or Ca2+. From uptake studies with 14C-labelled microcystins by zebrafish embryos (Wiegand et al. 1999), it was shown that even these substances with molecular masses of approximately 1.4 kDa can be taken up. This molecular mass, however, may be considered the upper threshold, and larger molecules will not pass this barrier. Control Luther Marsh Sanctuary Pond 700 Cadmium Uptake (pmol/g/h) Cadmium Uptake (pmol/g/h) 800 600 500 400 * 300 20 18 16 14 12 10 8 6 * * 4 2 0 Embryo * * 200 100 0 Chorion Perivitelline liquid Embryo Fig. 6: Cadmium accumulation in the chorion, perivitelline liquid and embryo in the presence of different DOM sources (16.9 mg L -1 C). Error bars represent standard deviation (n= 3) and the asterisk denotes a significant difference compared to the control at the p < 0.05 level. In all exposure groups only 1% of the total measured Cd was bound to the embryos. In the perivitelline fluid 38% (control), 31% (LM) and 24% (SP) of the total bound Cd was found. Thus, the accumulation in the respective egg components varies with the DOM source, too. However, Cd accumulated in the eggs was highest in the controls followed by SP and LM. Thus, the developing embryo was typically well protected from Cd pollution in the surrounding water by the chorion and this protection is enhanced in presence of DOM. Cd-accumulation in fish eggs is affected by several parameters like, Cdconcentration, exposure time, the presence of DOM. In particular, the presence of DOM, beside other factors like Ca2+-content and egg shell thickness, protects the developing fish embryos from Cd intoxication. Most of the Cd is bound to the egg chorion with even less in the presence of 128 DOM. Concentration of DOM as well as the source, and, thereby the chemical characterization of the DOM, must be take in consideration while estimating ecotoxicological effects of Cd on fish populations. Acknowledgement The project was financially supported by the DLR, Germany and Environment Canada. Dedicated to the memory of Dr. Richard C. Playle (1956-2005), an excellent scientist, colleague and good friend. References BEATTIE, J. H., PASCOE, D. (1978): Cadmium uptake by rainbow trout, Salmo gairdneri eggs and alevins. J. Fish Biol., 13, 631-637. BURNISON, B. K., MEINELT, T., PLAYLE, R. C., PIETROCK, M., WIENKE, A., STEINBERG, C. E. W. (2006): Cadmium accumulation in zebrafish (Danio rerio) embryos is modulated by dissolved organic matter. Aquat. Toxicol., 79, 185-191. COOPER, W. T., STENSON, A., MILLIGAN, L., CHANTON, J., DITTMAR, T., FILLEY, T. (2004): Ultrahigh resolution mass spectrometry of aquatic humic substances: Recurring molecular themes and polymeric character. In: MARTIN-NETO, L., MILORI, D. M. B. P., DA SILVA, W. T. L. (eds.): Humic Substances and Soil and Water Environment, Embrapa Instrumentacao Agropecuária, Sao Pedro. EN ISO 7346/3 (1996): International Organization for Standardization. Water quality - Determination of the acute lethal toxicity of substances to a freshwater fish [Brachydanio rerio Hamilton-Buchanan (Teleostei, Cyprinidae)] - Part 3: Flowthrough method. HAMMOCK, D., HUANG, C. C., MORT, G., SWINEHART, J. H. (2003): The effect of humic acid on the uptake of mercury (II), cadmium (II), and zinc (II) by chinook salmon (Oncorhynchus tshawytscha) eggs. Arch. Environ. Contam. Toxicol., 44, 8388. HATCHER, P., KIM, S., SUGIYAMA, Y. (2004): Intercomparisons of some new approaches for investigating the molecular weight distribution of dissolved organic matter. In: MARTIN-NETO, L., MILORI, D. M. B. P., DA SILVA, W. T. L. (eds.): Humic Substances and Soil and Water Environment, Embrapa Instrumentacao Agropecuária, Sao Pedro. JOHN, J., GJESSING, E. T., GRANDE, M., SALBU, B. (1987): Influence of aquatic humus and the pH on the uptake and depuration of cadmium by the Atlantic salmon (Salmo salar L.). Sci. Total Envir., 62, 253-265. LOZAN, J.L., KAUSCH, H., 2004: Angewandte Statistik für Naturwissenschaftler. Wissenschaftliche Auswertungen 2004, Hamburg. MEINELT, T., PLAYLE, R. C., PIETROCK, M., BURNISON, B. K., WIENKE, A., STEINBERG, C. (2001): Interaction of cadmium toxicity in embryos and larvae of zebrafish (Danio rerio) with calcium and humic substances. Aquat. Toxicol., 54, 205-215. MICHIBATA, H. (1981): Uptake and distribution of cadmium in the egg of the teleost, Oryzias latipes. J. Fish Biol., 19, 691-696. MICHIBATA, H., SAHARA, S., KOJIMA, M. K. (1986): Effects of calcium and magnesium ions on the toxicity of cadmium to the eggs of the teleost, Oryzias latipes. Env. Res., 40, 110-114. © IGB 2007 129 PENTTINEN, S., KUKKONEN, J., OIKARI, A. (1995): The kinetics of cadmium in Daphnia magna as affected by humic substances and water hardness. Ecotox. Environ. Safety, 30, 72-76. PETERSEN, R. C., HARGEBY, A., KULLBERG, A. (1987): Biological importance of humic material in acidified waters. A summary of the chemistry, biology and ecotoxicology of aquatic humus in acidified surface waters. National Swedish Environment Protection Board, Solna (Sweden), 149 pp. PETERSON, R. H., MARTIN-ROBICHAUD, D. J. (1986): Perivitelline and vitelline potentials in teleost eggs as influenced by ambient ionic strength, natal salinity, and electrode electrolyte; and the influence of these potentials of cadmium dynamics within the egg. Can. J. Fish. Aquat. Sci., 43, 1445-1450. PLAYLE, R. C. (1998): Modelling metal interactions at fish gills. Sci. Total Environ., 219, 147-163. PLAYLE, R. C., DIXON, D. G., BURNISON, K. (1993a) : Copper and cadmium binding to fish gills: estimates of metal-gill stability constants and modelling of metal accumulation. Can. J. Fish. Aquat. Sci., 50, 2678-2687. PLAYLE, R. C., DIXON, D. G., BURNISON, K. (1993b): Copper and cadmium binding to fish gills: modification by dissolved organic carbon and synthetic ligands. Can. J. Fish. Aquat. Sci., 50, 2667-2677. REEMTSMA, T., THESE, A. (2003): On-line coupling of size exclusion chromatography with electrospray ionization-tandem mass spectrometry for the analysis of aquatic fulvic and humic acids. Analyt. Chem., 75, 1500–1507. REEMTSMA, T., THESE, A., 2005: Comparative investigation of low-molecular-weight fulvic acids of different origin by SEC-Q-TOF-MS: New insights into structure and formation. Environ. Sci. Technol. 39, 3507–3512. RICHARDS, J. G., BURNISON, B. K., PLAYLE, R. C. (1999): Natural and commercial dissolved organic matter protects against the physiological effects of a combined cadmium and copper exposure on rainbow trout (Oncorhynchus mykiss). Can. J. Fish. Aquat. Sci., 56, 407-418. ROMBOUGH, P. J. (1985): The influence of the zona radiata on the toxicities of zinc, lead, mercury, copper and silver ions to embryos of steelhead trout Salmo gairdneri. Comp. Biochem. Physiol., 82, 115-117. ROMBOUGH, P. J., GARSIDE, E. T. (1982): Cadmium toxicity and accumulation in eggs and alevins of Atlantic salmon Salmo salar. Can. J. Zool., 60, 2006-2014. SEITZINGER, S. P., HARTNETT, H., LAUCK, R., MAZUREK, M., MINEGISHI, T., SPYRES, G., STYLES, R. (2005): Molecular-level chemical characterization and bioavailability of dissolved organic matter in stream water using electrosprayionization mass spectrometry. Limnol. Oceanography, 50, 1–12. Statistical Package for the Social Sciences, 1999 (SPSS for Window, Version 9.0.1) Chicago: SPSS, Inc., 11. March. WIEGAND, C., PFLUGMACHER, S., OBEREMM, A., MEEMS, N., BEATTIE, K. A., STEINBERG, C. E. W., CODD, G. A. (1999): Uptake and effects of microcystin-LR on detoxication enzymes of early life stages of the zebra fish (Danio rerio). Environ. Toxicol., 14, 89–95. 130 P OYNTON , S. L., S AGHARI F ARD , M. R., B LEISS , W., J ØRGENSEN , A., W EISHEIT , C., M EINELT , T., R ENNERT , B., C HENG , J., K IRSCHBAUM , F., K NOPF , K. 3.4.4 Towards improved management of infection in aquaculture: strategies arising from the hostparasite interactions in rainbow trout Oncorhynchus mykiss and the pathogenic flagellate Spironucleus salmonis Wege zu einem verbesserten Management von Infektionskrankheiten in der Aquakultur: Strategien basierend auf der Wirt-Parasit Interaktion zwischen der Regenbogenforelle Oncorhynchus mykiss und dem pathogenen Flagellaten Spironucleus salmonis Key words: diplomonad, Spironucleus salmonis, diagnosis, rainbow trout, Oncorhynchus mykiss, SSU rRNA gene, ultrastructure, encystment, susceptibility, life cycle Abstract Intensive aquaculture of rainbow trout, Oncorhynchus mykiss, provides an environment in which parasites can rapidly be transmitted. Among the common protozoan pathogens affecting farmed rainbow trout in Germany are diplomonad flagellates found in the lumen of the intestine. To provide new tools for management of the infections, we undertook studies to characterise the parasite, improve understanding of the life cycle, and develop a new test to predict host susceptibility. Ultrastructural studies confirmed the flagellate as Spironucleus salmonis, characterised by a smooth surface and a caudal projection. The sequence of the small subunit (ssu) rRNA gene and the microhabitat preference distinguish S. salmonis from other piscine diplomonads. Recognition of distinct stages in the transformation of active trophozoites into immobile resistant cysts, sometimes clustered in colonies, suggest new treatment targets. We have successfully modified a plasma incubation test, initially used for flagellates in the blood, and adapted for use with S. salmonis from the intestinal lumen. We can assess the effect of the plasma from different fish species on S. salmonis by using a combination of lysis, cytotoxicity, and time that the flagellates survived in the inoculation. Preliminary data shows a good correction between in vitro results and host susceptibility based on epizootiological data. Zusammenfassung Die intensive Aquakultur der Regenbogenforelle, Oncorhynchus mykiss, schafft Bedingungen, unter denen sich Parasiten sehr schnell ausbreiten können. Zu den bei kultivierten Regenbogenforellen in Deutschland gewöhnlich auftretenden einzelligen Krankheitserregern gehören diplomonade Flagellaten im Darmlumen der Fische. Um neue Verfahren zum Management der Infektionskrankheit zur Verfügung zu stellen, führten wir Untersuchungen zur Charakterisierung des Parasiten und zu einem besseren Verständnis dessen Entwicklungszyklus durch und entwickelten einen neuen Test, der Aussagen zur Empfänglichkeit eines Wirtes zulässt. Ultrastrukturelle Untersuchungen bestätigten, dass es sich bei dem Flagellaten um die Art Spironucleus © IGB 2007 131 salmonis handelt, welche durch eine glatte Oberfläche und einen caudalen Fortsatz charakterisiert ist. Die Sequenz des ssu rRNA Gens sowie das bevorzugte Mikrohabitat unterscheiden S. salmonis von anderen Diplomonaden in Fischen. Die Beobachtung spezieller Entwicklungsstadien während der Transformation von aktiven Trophozoiten zu enzystierten und manchmal kolonienbildenden Dauerstadien gibt Hinweise auf neue Behandlungsmöglichkeiten. Wir haben erfolgreich einen ursprünglich für Blutflagellaten verwendeten Plasma-Inkubationstest modifiziert und für die Verwendung mit S. salmonis angepasst. Mit der Beobachtung von Lyse, Zytotoxizität und Überlebensdauer der Flagellaten lässt sich der Effekt des Plasmas unterschiedlicher Fischarten auf S. salmonis bestimmen. Erste Daten zeigen eine gute Übereinstimmung der in vitro Ergebnisse mit epizootiologischen Untersuchungen zur Wirtsspezifität von S. salmonis. 3.4.4.1 Introduction Parasites as economic constraints in aquaculture Intensive aquaculture provides conditions in which parasites can florish, since fish are held at high stocking densities, and parasites can easily be transmitted from one fish to another. When parasite diseases occur in aquaculture, they can cause significant loss of stock via morbidity, and acute and chronic mortality, especially when husbandry standards are poor. In Germany, rainbow trout, Oncorhynchus mykiss is the principal farmed species, with the production of some 25,000 tonnes per year placing Germany among the top 10 producers of rainbow trout worldwide (Brämick 2004, FAO 2004). Among the commonly reported pathogens of rainbow trout in Germany, are diplomonad flagellates (Spironucleus spp.), found in the intestine and associated with weight loss and death of young fish (Roberts & Schlotfeldt 1985, Schäperclaus et al. 1990, Schlotfeldt & Aldermann 1995, Woo & Poynton 1995, Uldal & Buchmann 1996, Buchmann & Bresciani 2001). Despite their common occurrence, these protozoans are poorly characterised, and many aspects of the host-parasite interactions are unknown. Diplomonad flagellates In the trout, these small flagellates, approximately 10 µm long, are commonly found swimming in the intestinal lumen. This motile feeding stage, known as the trophozoite, can reproduce by longitudinal binary fission. Outside of the fish, the resistant cyst stage passes through the water, awaiting ingestion by a fish. When the cyst reaches the intestine, excystment occurs to release a trophozoite, thus the life cycle is completed (Woo & Poynton 1995). The literature is replete with taxonomic confusion over the true identity of the diplomonads in trout in Germany, and authors have commonly referred to them as Octomitus intestinalis truttae (Schmidt 1919) or Hexamita salmonis (Sanzin 1965, Schäperclaus et al. 1990, Schlotfeldt 1991), although Spironucleus is probably the correct genus (Poynton et al. 2004). Diagnosis, managing, and predicting infections Accurate identification of pathogens is a key element of effective monitoring and management of diseases. For diplomonad flagellates, we now recognise that while light 132 microscopy is helpful in confirming the presence of diplomonad flagellates, transmission electron microscopy (TEM) is essential for identification to genus (Brugerolle et al. 1973, Poynton & Sterud 2002). For identification to species, a comprehensive approach using ultrastructure and molecular characterisation is needed (Poynton & Sterud 2002). The ultrastructure alone is insufficient, since organisms that look the same may be differentiated based on sequence data from the ssu rRNA gene (Jorgensen & Sterud 2004, 2006). Furthermore, aspects of the relationship with the host are also important for characterisation of species (Poynton & Sterud 2002). For management of diplomonad infections in aquaculture, another key element is effective treatment of infections. Although the trophozoites can be treated with the drug metronidazole, which is usually given in the feed (Stoskopf 1993, Woo & Poynton 1995), this drug is not licenced for use in the EU (Buchmann & Bresciani 2001). To the best of our knowledge, there are no treatments targeted at the cyst stage of the parasite, and the mechanisms for transformation of trophozoites to cysts are poorly documented. With increasing concern about transmission of parasites and diseases between farmed and wild stock, it is important to recognise the range of hosts that a particular parasite can infect, and among these, the species in which disease is likely to occur. Susceptibility to infection by piscine diplomonads is currently determined by conducting experimental infections (Kent et al., 1992; Uzmann et al., 1965); however this is expensive and time consuming. In contrast, susceptibility to infection for some other flagellates can be determined based upon the innate immunity of the host, via in vitro testing using an incubation of host plasma and cultured parasites (Bower & Woo 1977; Wehnert & Woo 1980; Belosevic & Faubert 1987). Aims of our study To improve management of diplomonad infections in farmed rainbow trout we are focussing our attention on three aspects: (1) comprehensive characterisation of the parasite using ultrastructural, molecular, and ecological approaches, (2) improved understanding of the life cycle, via documentation of the transformation of trophozoites to cysts, and (3) development of a plasma incubation test to predict host susceptibility to infection. 3.4.4.2 Material and Methods Rainbow trout infected with diplomonads were collected from a farm near Berlin, and held at the Institute until the time of examination. Most of the fish were juveniles, 10 – 20 cm total length. Characterisation Diplomonads were processed in situ, and as cell suspensions, for the scanning and transmission electron microscopy studies (Saghari Fard et al. 2007). Particular features of taxonomic interest were the cell surface and the architecture of the posterior end (SEM), and the accessory cytoskeleton and cytoplasmic organelles (TEM). Our molecular characterisation focussed on sequencing of the small subunit (ssu) rRNA gene (Saghari Fard et al. 2007). For ecological characterisation, we considered the microhabitat preference of the diplomonads in the intestine of the fish, and © IGB 2007 133 documented the occurrence and density of the diplomonads, and the pH, in four regions of the intestine (pyloric, anterior, mid, and posterior) (Weisheit 2004). Life cycle The stages in the process of transformation of trophozoites to cysts were observed in organisms maintained in in vitro culture. Primary cultures were maintained in minimal essential medium (MEM) supplemented with calf serum, sodium bicarbonate solution, and antibiotics (Uldal 1996). The culture flasks were incubated at 10 ºC in the dark. For photography, samples were preserved in 3% glutaraldehyde in 0.1 M N-cacodylate buffer (pH 7.4). Predicting susceptibility We modified an in vitro plasma incubation technique previous used to determine susceptibility to the kinetoplastid hemoflagellates Cryptobia catastomi and Trypanoplasma salmositica (Bower & Woo 1977, Wehnert & Woo 1980). The basic premise of the test is that the plasma of susceptible hosts is relatively benign in its action on the flagellates, whereas plasma from resistant hosts is damaging, resulting in lysis and or cytotoxicity. Our initial studies were aimed at protocol development, and determination of parameters indicative of between-species differences in susceptibility to S. salmonis. We used rainbow trout as the susceptible host, and carp Cyprinus carpio and Atlantic sturgeon Acipenser sturio as resistant hosts (Cheng 2006). A 384-well tissue culture plate was used for our tests. The wells were loaded with culture medium, fresh plasma was added in 1:2 serial dilution (and tested from 1:4 to 1:2,048), and known numbers of trophozoites were added. Control wells contained medium and trophozoites, but no plasma. Experiments were conducted in triplicate. After setting up the inoculation, wells were examined at 5, 30, 60 and 120 minutes, and lysis and cytotoxicity were recorded (assessed as killed or missing cells and abnormal movement respectively). 3.4.4.3 Results Characterisation The pyriform trophozoite had a tapered posterior end, bearing a small caudal projection between the emerging posterior flagella (Fig. 1A - C); occassionally a vacuole was seen discharging through the surface (Fig. 1A). Bands of microtubules radiated out from around the flagellar pocket, lobed nuclei were intertwined, and there was a region of dense free ribosomes at the posterior end of the body. The ssu rRNA gene sequence clearly distinguished S. salmonis from three other Spironucleus species from fish, and a 1405 bp sequence used for phylogenetic analysis showed S. salmonis was a sister taxon to S. vortens (Saghari Fard et al. 2007). The diplomonads were at significantly higher occurrence and density in the pyloric region of the intestine than elsewhere. However microhabitat preference was not closely related to the pH profile (Weisheit 2004). 134 C B Fig. 1: Scanning electron micrographs of trophozoites of Spironucleus salmonis from rainbow trout Oncorhynchus mykiss. A. Unadorned body surface (an important diagnostic feature), the dark circular area is a discharging digestive vacuole. B. Tapered posterior of body. C. A species-specific feature, the small projection between the two emerging posterior flagella (from Saghari Fard et al. 2007). Life cycle studies Transformation of individual swimming trophozoites into colonies of immobile cysts could occur very rapidly. The process began by the flagella of trophozoites attaching to digesta or to each other (Fig. 2A), and ended with large aggregations or colonies of encysted flagellates (Fig. 2B). The attaching trophozoites changed their shape from pyriform to spherical, flagella could no longer be seen, and a cyst wall was formed. A B Fig. 2: Attachment, colony formation and encystment of Spironucleus salmonis. A. Single trophozoite recently attached to digesta; note that typical pyriform shape is retained. B. Colony, note that the cells have changed shape from pyriform to spherical. Colony has approximately 15 cells. Predicting susceptibility Integration of ten different parameters was investigated, and led to the development of a successful protocol for quantifying lysis and cytotoxicity (Cheng 2006). The survival of the trophozoites generally decreased with plasma concentration increase, and with duration of the incubation, for each of the three fish species. Data is shown for rainbow trout in Fig. 3. For determining the harmful effects of the plasma on the © IGB 2007 135 trophozoites, a combination of three criteria were considered: lysis (lytic titre), cytotoxicity, and time that the trophozoites remained alive in the plasma incubation. Preliminary data showed that plasma from sturgeon was more harmful to the trophozoites than was plasma from carp or rainbow trout, and that the trophzoites survived for the longest time in plasma from rainbow trout. 1.0 Survival of trophozoites 0.8 control 1:8 1:32 1:128 1:512 0.6 0.4 0.2 0.0 5 30 60 120 Time post inoculation (min) Fig. 3: Changes in survival of trophozoites in different plasma concentrations and at different times (rainbow trout, preliminary data). A survival score of 1.0 indicates that all the trophozoites survived. (From Cheng 2006) 3.4.4.4. Discussions Characterisation Our ultrastructural studies provided the first accurate identification of the genus and species of the diplomonad infecting rainbow trout in Germany (Saghari Fard et al., 2007). We observed a novel feature of taxonomic significance, namely the small caudal projection, and also proposed some new aspects of functional morphology based on the intertwined and multi-lobed apices of the nuclei. Recognition of the distinct sequence of the ssu rRNA gene, confirms the importance of the complimentary molecular approach to taxonomy of diplomonads, and provides valuable information for development of molecular probes for diagnosis. Our study of the microhabitat preference and pH is the first to investigate physiochemical factors and microhabitat of piscine diplomonads. Life cycle We were able to observe the transformation of trophozoites to cysts in vitro, and believe that this is a good model for studying what happens in vivo, since cysts have been reported for S. salmonis (Moore 1922, Davis 1926), and colonies of cysts are known for other diplomonads (Wood & Smith 2005). Identification of the environmental triggers prompting the transformation (presumably encountered in vivo when the trophozoites pass from the fish into the water), would be an important next step in understanding the process, and may lead to recognition of new targets for treatments based on inhibition of encystment. This would be an important new approach, since present treatments target the trophozoites in the fish, rather than the cysts which transmit the infection. 136 Predicting susceptibility We have successfully modified a plasma incubation test originally devised for kinetoplastids in the blood (Bower & Woo 1977, Wehnert & Woo 1980) for a new application with diplomonad flagellates from the lumen of the intestine. Demonstration of the dose-response effect of the plasma was an essential prerequisite to further development of the plasma incubation test. Our preliminary data on between-species susceptibility shows promise, since our plasma incubation tests suggest the same patterns of susceptibility to S. salmonis as seen from epizootiological data. Further development of our new test will involve testing large numbers of individual fish of different species, and naive and exposed individuals of the most susceptible species, the rainbow trout. Exploration of the mechanisms of the innate immunity that are manifest in the test is also planned. Recommendations Recognition of distinct sequences in the ssu rRNA gene offers the possibility for development of molecular probes for different piscine diplomonad species, which could supplement ultrastructural diagnosis, and would be more accurate. Development of new treatments can include agents that inhibit the transformation of trophozoites to resistant cysts, thus offering a crucial alternative to the present situation, where the effective treatment against trophozoites is not permitted for use in many countries. Development of the plasma incubation test holds considerable promise for predicting host susceptibility to S. salmonis, and would be a cheaper and less expensive approach than the present tests, which require experimental infections. Acknowledgement We are pleased to thank Mr. Matthias Kunow, Fisherman, for assistance with collecting rainbow trout and maintaining them at the Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin (IGB). Ms. Anorte Marko (Molecular Parasitology, Humboldt University, Berlin) graciously undertook initial sample processing of electron microscopy samples. Mr. Michael Delannoy from Johns Hopkins University, School of Medicine, Baltimore, and Ms. Else Engeland from the National Veterinary Institute, Oslo also processed some TEM samples. For our ultrastructure and molecular investigations, we were most fortunate to have had the assistance of Dr. Erik Sterud, of the National Veterinary Institute in Oslo. We also thank Ms. Magdalena Sieber and Ms. Ute Hentschel from IGB, and Ms. Cathy Rada of the Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, for their assistance with obtaining literature for us. We are grateful to our colleagues from IGB: Prof. Werner Kloas for support, Dr. Klaus Kohlmann for advice on the molecular aspects of the study, and Mr. Jörn Gessner for providing blood samples from sturgeon. We gratefully acknowledge the Nachwuchsförderung des Landes Berlin (NaFöG) for the award of a Ph.D. scholarship to Mr. M. Reza Saghari Fard, the Amt für Ausbildungsförderung for Bafög to Ms. Claudia Weisheit, and the Deutsche Forschungsgemeinschaft for the award of a Mercator Visiting Professorship to Dr. Sarah Poynton. © IGB 2007 137 References BELOSEVIC, M., FAUBERT, G. M. (1987): Lysis and immobilization of Giardia muris trophozoites in vitro by immune serum from susceptible and resistant mice, Parasite Immunol. 9, 11-19. BOWER, S. M., WOO, P. T. K. (1977): Cryptobia catastomi: incubation in plasma of susceptible and refractory fishes. Exp. Parasitol., 43, 63-68. BRÄMICK, U. (2004): Binnenfischerei 2003. In: DÖLLING, R. (ed.): Jahresbericht über die Deutsche Fischwirtschaft 2004. Bundesministerium für Verbraucherschutz, Ernährung und Landwirtschaft, DCM Verlag, Meckenheim, 47-77. BRUGEROLLE, G., JOYON, L., OKTEM, N. (1973) : Contribution a l’étude cytologique et phylétique des diplozoaires (Zoomastigophorea, Diplozoa; Dangeard 1910). II. Étude ultrastructurale du genre Spironucleus (Lavier 1936). Protistologica, 9, 495-502. BUCHMANN, K., BRESCIANI, J. (2001): An introduction to parasitic diseases of freshwater trout. DSR Publishers, Frederiksberg C. CHENG, J. (2006): Development of a modified plasma incubation test for detecting susceptibility to the piscine diplomonad Spironucleus salmonis. MS thesis, Humboldt University in Berlin, Germany. DAVIS, H. S. (1926): Octomitus salmonis, a parasitic flagellate of trout. Bull. US. Bur. Fish., 42, 9-26. FAO (2004): FAO Yearbook. Fishery statistics. Aquaculture production 94/2. FAO, Rome. JØRGENSEN, A. STERUD, E. (2004): SSU rRNA gene sequence reveals two genotypes of Spironucleus barkhanus (Diplomonadida) from farmed and wild Arctic charr Salvelinus alpinus. Dis. Aquat. Org., 62, 93-96. JØRGENSEN, A. STERUD, E. (2006): The marine pathogenic genotype of Spironucleus barkhanus from farmed salmonids redescribed as Spironucleus salmonicida n. sp. J. Eukaryot. Microbiol., 53, 531-541. KENT, M. L., ELLIS, J., FOURNIE, J. W., DAWE, S. C., BAGSHAW, J. W., WHITAKER, D. J. (1992): Systemic hexamitid (Protozoa: Diplomonadida) infection in seawater pen-reared Chinook salmon Oncorhynchus tshawytsha. Dis. Aquat. Org., 14, 81-89. MOORE, E. (1922): Octomitus salmonis, a new species of intestinal parasite in trout. Trans. Am. Fish. Soc., 52, 74-97. POYNTON, S. L., STERUD, E. (2002): Guidelines for species descriptions of diplomonad flagellates from fish. J. Fish. Dis., 25, 15-31. POYNTON, S. L., SAGHARI FARD, M. R., JENKINS, J., FERGUSON, H. W. (2004): Ultrastructure of Spironucleus salmonis n. comb. (formerly Octomitus salmonis sensu Moore 1922, Davis 1926, and Hexamita salmonis sensu Ferguson 1979), with a guide to Spironucleus species. Dis. Aquat. Org., 60, 49-64. ROBERTS, R. J., SCHLOTFELDT, H-J. (1985): Grundlagen der Fischpathologie mit einer Einführung in die Anatomie, Physiologie, Pathophysiologie und Immunologie sowie in den aquatischen Lebensraum der Knochenfische. Paul Parey, Berlin. SAGHARI FARD, M. R., JØRGENSEN, A., STERUD, E., BLEISS, W., POYNTON, S. L. (2007): Ultrastructure and molecular diagnosis of Spironucleus 138 salmonis (Diplomonadida) from rainbow trout Oncorhynchus mykiss in Germany. Dis. Aquat. Org., 75, 37-50. SANZIN, W. D. (1965): Untersuchungen zur Ökologie, Artspezifität und Variabilität von Hexamita salmonis Moore. Ph.D. Dissertation in Ludwig-Maximilians University of Munich. SCHÄPERCLAUS, W., KULOW, H., SCHRECKENBACH, K. (1990): Fischkrankheiten Teil 2. Akademie-Verlag, Berlin. SCHLOTFELDT, H-J. (1991): Was tun, wenn …? ein Leitfaden für den praktischen Fischzüchter, Teichwirt und Fischhalter. Staatlicher Fischseuchenbekämpfungsdienst Niedersachsen und Fischgesundheitsdienst, Hannover. SCHLOTFELDT, H-J., ALDERMAN, D. J. (1995): What should I do? A practical guide for the freshwater fish Farmer. Bull. Eur. Assoc. Fish. Pathol. (suppl), 15, 28-29. SCHMIDT, W. (1919): Untersuchung über Octomitus intestinalis truttae. Arch. Protistenkd, 40, 253-289. STOSKOPF, M. K. (1993): Fish Medicine. WB Saunders Co, Philadelphia. ULDAL, A. (1996): Life cycle observations on Hexamita salmonis from rainbow trout intestine. In vitro studies. Bull. Eur. Ass. Fish. Pathol., 16, 112-114. ULDAL, A., BUCHMANN, K. (1996): Parasite host-relations: Hexamita salmonis in rainbow trout Oncorhynchus mykiss. Dis. Aquat. Org., 25, 229 – 231. UZMANN, J. R., PAULIK, G. J., HAYDUK, S. H. (1965): Experimental hexamitiasis in juvenile Coho salmon (Oncorhynchus kisutch) and Steelhead trout (Salmo gairdneri). Trans. Amer. Fish. Soc., 94, 53-61. WEHNERT, S. D., WOO, P. T. K. (1980): In vivo and in vitro studies on the host specificity of Trypanoplasma salmositica. J. Wildl. Dis., 16, 183-187. WEISHEIT, C. (2004): Ökologie von Diplomonadflagellaten in Regenbogenforellen aus Aquakultur. B. Sc. Thesis, Faculty of Agriculture and Horticulture, Humboldt University, Berlin. WOO, P. T. K., POYNTON, S. L. (1995): Diplomonadida, Kinetoplastida and Amoebida (Phylum Sarcomastigophora). In: WOO, P. T. K. (ed.): Fish Diseases and Disorders, Vol 1, Protozoan and Metazoan Disorders. CAB International, Wallingford, 27-96. WOOD, A. M., SMITH, H. V. (2005): Spironucleosis (Hexamitiasis, Hexamitosis) in the ring-necked pheasant (Phasianus colchicus): detection of cysts and description of Spironucleus meleagridis in stained smears. Avian Dis., 49, 138 – 143. © IGB 2007 139 OGUNJI, J., SUTTER, D., RENNERT, B., KLOAS, W., SCHULZ, C. 3.4.5 Growth performance and body composition of carp (Cyprinus carpio) fed diets containing housefly maggot meal (magmeal) Wachstum und Körperzusammensetzung von Karpfen (Cyprinus carpio) denen Futtermittel mit Fliegenmadenmehl verabreicht wurden Key words: housefly maggot meal, fishmeal, cyprinus carpio, growth performance Abstract In order to evaluate housefly maggot meal (magmeal) as feed ingredient for carps (Cyprinus carpio) juveniles triplicate groups were fed with five isonitrogenous feeds (crude protein: 401 – 418 g kg-1) with varying protein sources. Fishmeal based protein content of diets was substituted with 0 (diet C), 150 (diet A1), 450 (diet A2), 670 (diet A3), and 860 g kg-1 (diet A 4) magmeal. Carp juveniles were fed a fixed ration at a level of 15 % body weight in 6 portions per day. Highest individual weight gain, specific growth rate and best feed conversion ratio were observed in carp fed diet A1 followed by fish fed diet A2 and diet C without any significant differences. Higher magmeal inclusion in diets A3 and A4 decreased fish growth performance significantly and also the body lipid concentration. Dietary inclusion of magmeal up to the level of 450 g kg-1 would improve optimal growth performance of carp. In such a combination magmeal is able to supply above 50 % crude protein needed in the carp diet. Zusammenfassung Kommerzielles Fischfutter basiert im Allgemeinen auf Fischmehl als Proteinquelle. Jedoch ist Fischmehl eine teure und wenig umweltfreundliche Proteinquelle. Deshalb wird nach Alternativen gesucht. Eine davon könnte Fliegenmadenmehl sein. Ziel der Untersuchungen war, Fliegenmadenmehl als Bestandteil im Futter für junge Karpfen (Cyprinus carpio)zu testen. Dazu wurden junge Karpfen in jeweils drei Wiederholungen mit fünf Futtermitteln gefüttert, die nahezu gleiche Proteingehalte (401- 418 g kg-1) von unterschiedlichen Proteinquellen aufwiesen. Der Fischmehlanteil wurde im Futter A1 durch 150 g kg-1, in Futter A2 durch 450 g kg-1, in Futter A3 durch 670 g kg-1 und in Futter A4 durch 860 g kg-1 Fliegenmadenmehl ersetzt. Futter C enthielt kein Fliegenmadenmehl und diente als Kontrolle. Den Karpfen wurden täglich Futtermengen in Höhe von 15 % ihrer Körpermasse in 6 Portionen verabreicht. Den besten Zuwachs, die höchste spezifische Wachstumsrate und den niedrigsten Futteraufwand wies Futter A1 auf. Es folgten die Futtermittel A2 und C. Die Unterschiede waren statistisch nicht signifikant. Höhere Anteile an Fliegenmadenmehl in den Futtermitteln A3 und A4 verringerten das Wachstum der Karpfen signifikant. Der Körperfettgehlt nahm ebenfalls ab. Es wird geschlussfolgert, dass ein Anteil 140 des Fliegenmadenmehls bis zu 450 g kg-1 das Wachstum der Karpfen verbessert. So können über 50 % des Rohproteins im Karpfenfutter aus Fliegenmadenmehl abgedeckt werden. 3.4.5.1 Introduction Commercial aqua feed has been traditionally based on fish meal as a main protein source due to its high protein content and balanced amino acid profile. In addition to its excellent supply of essential fatty acid (EFA), mineral and vitamins (Tacon 1993) fishmeal is also very palatable and highly digestible to most fresh water and marine fishes (Watanabe et al. 1997). Rapid increase in aquaculture industry all over the world demands fish meal in greatly higher quantity. Although the production of fish meal and fish oil remained constant over the last two decades at around 6200 – 7000 t/a relative amount used in fishfeed increased from 15 % in 1980 up to 43 % in 2002 (FAO 2002). These facts have made fish meal an expensive protein source for feed formulation in aquaculture (El-Sayed et al. 2000). As a consequence alternative protein sources for aquaculture fish food are being sought after. Housefly maggot meal (magmeal) as a protein source in fish diets has been evaluated in tilapia and catfish species respectively (Adesulu & Mustapha, 2000; Fasakin et al. 2003; Ajani et al. 2004). No trial so far has been reported with carp. It has been shown that magmeal is of high biological value and that the percentage of crude protein ranges from 40 to 61.4 % dry matter (dm). It is also rich in phosphorus, trace elements and B complex vitamins (Teotia & Miller, 1973; Spinelli et al. 1979; Ajani et al. 2004). Examination of the comparative amino acid profiles of fish and fly larvae protein showed that no essential amino acid was limiting (Spinelli et al. 1979). Ajani et al. (2004) and Fashina-Bombata & Balogun (1997) reported that magmeal can replace up to 100 percent of fish meal in the diets of Nile tilapia (Oreochromis niloticus). The objective of this study is to assess the growth performance and body composition of carp (Cyprinus carpio) fed diets containing housefly maggot meal (magmeal). 3.4.5.2 Material and Methods Culture system Experimental fish were reared in two recirculation systems each comprising of nine tanks (individual volume: 28 x 28 x 51.5 cm) and a filtration unit with a sedimentation chamber for settlement of particulate matter and a biological filter. Mean and standard deviation (±) of water temperature, pH, and O2content (measured with WTW multi 340 I, Weilheim, Germany) during the experiment were similar in all recirculation systems: 25.95 °C (± 0.52, System A), 25.95 °C (± 0.52, System B), 25.95 °C (± 0.52, System C); 7.66 (± 0.42), 7.57 (± 0.48), 7.65 (± 0.35) and 8.46 mg l-1 (± 1.19), 8.55 mg l-1 (± 0.94), 8.51 mg l-1 (± 0.79). The average concentration of total ammonia during the experiment was 0.25 mg l-1. © IGB 2007 141 Experimental diets Formulation and chemical composition of experimental diets are shown in Table 1 and 2. Five isonitrogenous diets were formulated to yield a content of around 41 % crude protein dry mattter (dm) using fishmeal and magmeal as major dietary protein sources. Fishmeal concentration in the diets decreased with increasing concentration of magmeal. Diet C, formulated with the highest inclusion level of fish meal and without magmeal served as the control. Though 10 g kg-1 of chromic oxide was included in all diets, no fish faeces were collected for digestibility determination as it was initially planned. Silicate gel was used to balance the nutrient content of the diets. All dry diet components, including vitamin and mineral mixture, were thoroughly mixed with oil. Water was added and the feed pressed into pellets of 1 mm diameter. The wet pellets were dried for 3 days at room temperature and stored at -2 °C until used. Table 1: Ingredients used for experimental diet formulation [g kg-1] Diets Feed Stuff 1 C A1 A2 A3 A4 FishMeal 620 520 300 150 - Magmeal - 150 450 670 860 Soymeal - - - - - Wheat Flour 160 150 130 100 100 Fish Oil 70 60 30 - - Canola Oil 80 60 30 20 10 Vit./Min Mix 2 20 20 20 20 20 Silicate gel 40 30 30 30 - Chromic Oxide 10 10 10 10 10 1 C = Control; 2Vitamin and Mineral mix (Spezialfutter Neuruppin - VM BM 55/13 Nr. 7318) supplied per 100 g of dry feed : Vitamin A 12000 I.E; Vitamin D3 1600 I.E; Vitamin E 160 mg; Vitamin K3 6.4 mg; Vitamin B1 12 mg; Vitamin B2 16 mg; Vitamin B6 12 mg Vitamin B12 26.4 mg; Nicotinic acid 120 mg; Biotin 800 mg; Folic acid 4.8 mg; Pantothenic acid 40 mg, Inositol 240 mg; Vitamin C 160 mg; Antioxidants (BHT) 120 mg; Iron 100 mg; Zink 24 mg; Manganese 16 mg; Cobalt 0.8 mg; Iodine 1.6 mg; Selenium 0.08 mg Experimental fishes and feeding trial Experimental fish were obtained from Warmwasserfischzucht Jäntschwalde, three days after hatching. They were brought to the facilities of Institute of Freshwater Ecology and Inland Fisheries Berlin Germany, where the carps were reared and acclimatized for six weeks. Prior to the commencement of growth trial, ten carps each with an initial average body weight of 0.74 g were randomly distributed in fifteen tanks. Experimental diets were assigned to the carps in triplicate tanks respectively in a way that all feeding groups were represented in the two recirculation systems evenly. The fish were given restricted ration at a level of 15 % body weight in 6 portions at 8.00, 10.00, 12.00, 14.00, 16.00, 17.30 hours respectively per day. Bryant & Matty (1981) suggested that carp fry (100 mg to 3g) required 10 – 15 % body weight per 142 day for optimum growth at water temperatures of 24 °C. This feeding level was reduced to 10 % body weight after three weeks when fish failed to consume their total ration. The fish were weighed every two weeks and quantity of food adjusted accordingly. Experimental tanks were cleaned regularly, and the trial lasted for 43 days (Molnar et al. 2006). Sample collection At the end of the experiment, four fish from each tank were randomly taken. The fish were weighed before the length of each fish was taken and liver excised and weighed. The rest 6 fish in all the tanks respectively were killed, individually weighed and measured before they were homogenised and freeze dried at a temperature of – 54 °C. Twenty fish samples sacrificed and homogenised at the beginning of the experiment were also freeze dried before being analysed for initial whole body composition. Table 2: Proximate nutritional and amino acid composition (g kg-1 dry matter) of experimental diets, values are means of duplicate determinations. Proximate composition Diets C A1 A2 A3 A4 Dry Matter (Dm) 953 951 954 945 927 Crude protein (Cp) 417 418 410 411 401 Crude lipid (Cl) 205 215 217 219 255 Crude ash 181 170 163 160 126 NFE 1 198 197 210 210 218 Gross Energy (MJ kg-1) 2 21.61 22.01 22.13 22.24 23.57 P/E ratio 3 19.30 18.99 18.53 18.48 17.01 Alanine 47.1 47.0 45.8 37.8 38.2 Arginine* 25.2 29.2 26.1 25.8 28.2 Aspartic acid 34.2 63.5 65.1 58.1 62.1 Glutamic acid 122.1 123.0 119.7 98.4 103.2 Histidine* 23.3 21.0 30.2 25.2 30.8 Isoleucine* 33.1 32.7 33.4 28.3 29.5 Leucine* 16.9 18.5 16.8 14.1 14.4 Lysine * 25.7 26.8 26.4 22.0 23.4 Phenylalanine* 36.1 34.5 40.7 39.9 44.7 Serine 26.4 26.8 26.2 21.4 21.8 Taurine 12.8 13.4 10.9 13.7 10.6 Threonine* 18.0 19.0 19.3 13.3 14.0 Tryptophan* 2.2 2.9 1.9 3.0 1.6 Tyrosine 4.4 2.4 3.5 3.6 4.5 Valine* 28.3 28.1 29.9 25.9 27.7 Total 455.80 488.80 495.90 430.50 454.70 Amino Acids 1 Nitrogen free extract + fibre, (NFE) = 100 - (% protein + % fat + % ash); 2Calculated by: Crude protein = 23.9 MJ kg-1 Crude lipids = 39.8 MJ kg-1, NFE = MJ kg-1 (Schulz et al., 2005); 3P/E = Protein to energy ratio in g protein / MJ gross energy; *Essential amino acids © IGB 2007 143 Chemical analysis The freeze-dried samples of fish and experimental diets were analyzed for proximate composition. Every analysis was carried out in duplicate and fish samples per tank. Protein (N x 6.25) was analysed using a Kjeltec System (Tecator) and crude fat using a Soxtec System HT (Tecator) with petroleum ether as the solvent. Ash was determined by burning in a muffle furnace at 550 °C for 10 hours. Gross energy was calculated using the following values: crude protein = 23.9 kJ g-1, crude lipids = 39.8 kJ g-1 and NFE = 17.6 kJ g-1 (Schulz et al. 2005). To estimate the amino acid concentrations of the experimental diets, 5 mg of the freeze-dried samples were hydrolyzed with 6N HCl at 110 °C for 24 hours. No protecting reagents were added to avoid destruction of sulphur amino acids that methionine values determined were very insignificant and are not reported here. Other analytical procedures for amino acids followed the description of Ogunji & Wirth (2001). Statistical analysis All data were subjected to one-way analysis of variance (ANOVA). The significance of difference between means was determined by Duncan’s multiple range test (P < 0.05) using SPSS for Windows (Version 12). Values are expressed as means ± SE. 3.4.5.3 Results Growth performance and food utilisation The effect of magmeal diets on growth performance and feed utilisation of Cyprinus carpio are shown in Table 3. During the experiment no mortality was recorded. Reduction of fishmeal from 620 g kg-1 (supplying 411.7 g kg-1 crude protein) in control diet to 530 g kg-1 (supplying 351.9 g kg-1 crude protein) and 300 g kg-1 (supplying 199.2 g kg-1 crude protein) respectively, by substituting with 150 g kg-1 magmeal (supplying 69.8 g kg-1 crude protein) in diet A1 and 450 g kg-1 magmeal (supplying 209.52 g kg-1 crude protein) in diet A2 improved final fish weight gain, specific growth rate (SGR), food conversion ratio (FCR) and hepatosomatic index (HIS), but no significant differences were observed (p> 0.05). No significant differences in FCR and HIS were also observed when magmeal was included in the carp diet at a level of 670 g kg-1 (supplying 312 g kg-1 crude protein) to diet A3. At this level however SGR decreased significantly. Diet A4 with magmeal as sole protein source yielded a significant lowest fish growth performance. Fish fed control diet recorded the highest condition factor (Cf 1.76). 144 Table 3: Mean and standard error (±) of growth performance parameter of Cyprinus carpio fed experimental diets; values are mean of triplicate feeding groups; within each line values with different superscript letter differ significantly (p< 0.05). Parameters Diets C A2 A3 A4 Initial weight (g) 0.73±0.01 a 0.73±0.01a 0.74±0.01a 0.75±0.01a Final weight (g) 7.90±0.36ab 9.44±0.55a 8.59±0.66a 6.35±0.53ab 4.38±0.28c Weight gain (g) 7.17±0.09ab 8.70±0.54a 7.86±0.63a 5.60±0.63b 3.63±0.37c Diet fed (g fish -1 ) 9.57±0.13a 10.49±0.35a 9.76±0.49a 8.32±0.44b 6.99±0.25c b 2.15±0.08c 1.96±0.18b SGR 1 A1 2.79±0.02 a a 0.75±0.01 2.92±0.05 a 2.87±0.07 a 2.53±0.07 FCR2 1.34±0.02a 1.21±0.04a 1.25±0.04a 1.50±0.08a HSI 3 2.52±0.14a 2.40±0.10a 2.15±0.14a 2.31±0.12a 2.47±0.21a Cf 4 1.76±0.02a 1.69±0.03a 1.61±0.02b 1.56±0.02b 1.59±0.04b Survival (%) 100 100 100 100 100 1 Specific growth rate (% day-1) = (InW 2 - InW1/ T2 -T1) × 100 2 Food conversion ratio = total diet fed (g)/live weight gain (g); 3 Hepatosomatic Index = [liver weight (g)/total fish weight (g)] * 100, based on a sub-sample of n = 12 per experimental group 3 Condition factor = W2 * L2 -3 * 100 (L = total length) Body composition Whole body crude protein, crude lipid and crude ash content increased in all experimental groups when compared to the initial status (Table 4). The crude protein varied between 131.6 g kg-1 (A4) and 133.6 g kg-1 (A3) without significant differences (p> 0.05) between all feeding groups. Carps fed control and A1 diets recorded highest body crude fats which decreased significantly with increasing dietary magmeal inclusion. Ash concentration in carps fed diet C (19.3 g kg-1) was significantly lower than in other groups (p< 0.05). No significant difference in body ash contents was observed between fish fed diet A1 to A4 (P < 0.05). Table 4: Mean and standard error (±) of initial and final composition of carp (whole fish) fed experimental diets; values are expressed as g kg -1 of original matter (o.m.); within each line values with different superscript letter differ significantly (p<0.05). Components Initial status 3.4.5.4 C Diets A2 A1 a A3 A4 a Moisture 824.5±0.03 730.9±0.34 734.0±0.31 754.8±0.09b 767.5±0.11c 767.7±0.37 c Crude protein 118.5±0.01 133.2±0.09a 132.4±0.20a 132.8±0.14a 133.6±0.10a 131.6±0.08a Crude lipid 24.3±0.02 a a b 106.9±0.35 100.7±0.20 79.3±0.08 Crude ash 19.3±0.00 19.3±0.07 NFE 13.5±0.00 9.7±0.15a a 21.8±0.10 b 11.2±0.09a 21.3±0.06 b 11.8±0.08a 63.3±0.07c 68.2±0.33c b 22.5±0.04b 12.8±0.10a 10.0±0.08a 22.7±0.24 Discussion In this study a complete replacement of fishmeal with magmeal in carp diet (diet A4) adversely affected growth performance (SGR 2.15; FCR 1.96) compared to the control. In contrast 100 % replacement has been reported for tilapia Oreochromis niloticus without any growth inhibition (Ajani et al. 2004 Fashina-Bombata & Balogun 1997). Since the amino acid dietary composition meets the requirement for carp, such reduced growth © IGB 2007 145 performance when magmeal completely substitute fishmeal may be due to inefficient utilisation of magmeal protein by carp resulting from low digestibility. Magmeal used for diet formulation contained an acid detergent fibre (ADF) concentration of 137.8 g kg-1. Most fish can tolerate up to 8 % fibre in their diets, but higher concentrations (8 to 30 %) depress growth (Edwards et al. 1977, Hilton et al. 1983, Poston 1986). According to Schwarz & Kirchgeßner (1982) carp is not able to digest fibre. Fasakin et al. (2003) reported that the reduction in growth performance of African catfish fed full–fat maggot meal may be, among other reasons due to low protein digestibility of magmeal. The weight gain and SGR of carp improved as fish meal was replaced in experimental diets with magmeal up to an incorporation level of 450 g kg-1 (diet A2). There seem to be a form of nutrient fortification when fishmeal is combined with magmeal in the diet of carp up to a certain level. It is however; unclear the particular nutrients that were improved giving the fact that the dietary amino acid composition seem similar (Table 2). Adesulu & Mustapha (2000) reported that the levels of some essential amino acids in magmeal were higher than that in fish meal and soybean meal. Examination of the comparative amino acid profiles of fishmeal and fly larvae protein in rainbow trout showed that no essential amino acid was limiting (Spinelli et al. 1979). The condition factor (Cf 1.76) of carps fed control diet in this study however, was highest though not significantly different from diet A1. Fishmeal is considered the most desirable animal protein ingredient in aquaculture diets (Muzinic et al. 2006). Yerli & Zengin (1996) reported a condition factors for the total, male and female of C. carpio between 1.45 – 2.08 and 1.74 – 2.47 respectively. Balik et al. (2004) determined that the condition factor of both sexes of silver crucian carp increased gradually with age. The FCR of carps fed diets A1 – A3 containing various percentages of magmeal were not significantly different, ranging from 1.21 (diet A1) to 1.50 (diet A3). De Silva & Anderson (1995) suggested that low FCR values indicate an improved feed outcome. Values as low as 1.0 have been reported although, generally they range between 1.2 and 1.5 for fish fed carefully prepared diets. As such incorporation of magmeal in carp diets, above the level 450 g kg-1 (supplying 209.5 g kg-1 dietary protein) (diet A2; FCR 1.25) and below 670 g kg-1 (supplying 312 g kg-1 dietary protein) (diet A3; FCR 1.5) would seem to enhance optimal growth performance of carp and provide outstanding economic advantage. This may allow for less expensive diet formulations for carps and reduce diet cost for producers, thereby increasing profitability. According to Fashina-Bombata and Balogun (1997) the replacement of fish meal by magmeal is economically feasible. The cost of harvesting and processing one kilogramme of magmeal is less than 20 % of cost of 1 kilogramme of fish meal. Whole body analysis shows that the level of magmeal in the experimental diets did not influence the HSI. The HSI in all feeding groups was not significantly different indicating that the proportion of lipid and carbohydrate incorporated into all experimental diets was optimal for carp 146 utilisation. Hemre et al (1989) suggested that fish even convert carbohydrate to lipid which are stored in the liver and thus affect the liver index. In this study the dietary lipid content (205 g kg-1; diet C – 255 g kg-1; diet A4) increased with elevated magmeal incorporation due to the high concentration of lipid in magmeal (258.2 g kg-1). The whole body moisture composition increased with increasing dietary lipid while the body crude lipid decreased. 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WICHELS, A., WUERTZ, S., DOEPKE, H., SCHUETT, C., GERDTS, G. (2006): Bacterial diversity in the breadcrumb sponge Halichondria panicea (Pallas). FEMS Microbiology Ecology, 56, 102-108. WIESE, B., PALANCAR, M. C., ARAGON, J. M., SANCHEZ, F., GIL.R. (2006): Modelling the Entreperias reservoir. Water Environment Research, 78, 781-791. WILHELM, S., HINTZE, T., LIVINGSTONE, D. M., ADRIAN, R. (2006): Longterm response of daily epilimnetic temperature extrema to climate © IGB 2007 159 forcing. Canadian Journal of Fisheries and Aquatic Sciences, 63, 24672477. WOLTER, C. (2006): First record of river gudgeon Romanogobio belingi in the River Havel, Brandenburg, Germany. Lauterbornia, 56, 91-94. WUERTZ, S., NITSCHE, A., GESSNER, J., KIRSCHBAUM, F., KLOAS, W. (2006): IGF-I and its role in maturing gonads of female sterlet, Acipenser ruthenus Linnaeus, 1758. Journal of Applied Ichthyology, 22, 346-353. WUERTZ, S., LUTZ, I., GESSNER, J., LOESCHAU, P., HOGANS, B., KIRSCHBAUM, F., KLOAS, W. 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Limnologica, 36, 1. 160 4.2 Non-reviewed papers, books, book chapters and reports Artikel in nichtreferierten Zeitschriften, Bücher, Buchbeiträge und Berichte ARLINGHAUS, R. (2006): Der unterschätzte Angler. Kosmos Verlag, Stuttgart, 168 S. ARLINGHAUS, R., LEWIN, W.-C. (2006): Dokumentierte und vermutete Auswirkungen einer intensiven Angelfischerei und Ausblick für das Management. In: Leibniz-Institut für Gewässerökologie und Binnenfischerei (ed.): Integrierter Gewässerschutz für Binnengewässer: Maßnahmen zum nachhaltigen Umgang mit der Ressource Wasser. Leibniz-Institut für Gewässerökologie und Binnenfischerei, Stechlin, 5576. BLANK, B., MEIßNER, R., NEEF, T., STRAUCH, G., NÜTZMANN, G. (2006): Investigating heterotrophic denitrification in shallow groundwater of the Schaugraben catchment, NE Germany. In: KOVAR, K., HRKAL, Z.,.BRUTHANS, J. (eds.): Hydrology and Ecology: The Groundwater/Ecology connection, 137-140. 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BRÜGGEMANN, R., RESTREPO, G., VOIGT, K. (2006): Evaluation of the Pollution State in Baden-Wuerttemberg by a Local Analysis. In: STUDZINSKI, J., HRYNIEWICZ, O. (eds.): Development of Methods and Technologies of Informatics for Process Modeling and Management. Polish Academy of Sciences, Systems Research Institute, Warsaw, 121135. BRÜGGEMANN, R., RESTREPO, G., VOIGT, K. (2006): Structure-FateRelationships of Organic Chemicals. In: VOINOV, A., JAKEMAN, A.J., RIZZOLO, A. E. (eds.): Proceedings of the iEMSs Third Biennial Meeting: "Summit on Environmental Modelling and Software", 1-6. © IGB 2007 161 BRÜGGEMANN, R., SIMON, U., NÜTZMANN, G. (2006): Analyzing water management strategies in urban regions by directed graphs. In: STUDZINSKI, J., HRYNIEWICZ, O. (eds.): Modeling concepts and decision support in environmental systems. Polish Academy of Sciences, Warsaw, System research, 111-124. BRUNKE, M. (2006): Meio- und Makrofauna der überströmten Sohle. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 181-190. BRUNKE, M. (2006): Mikrofauna. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 139144. BRUNKE, M., GRAFAHREND-BELAU, E., PUSCH, M. (2006): Bedeutung von Totholz für das Makrozoobenthos. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 278284. BRUNKE, M., GUHR, H. (2006): Auswirkungen der Schifffahrt. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 286-294. BRUNKE, M., PUSCH, M. (2006): Prozesse und Biozönosen an der überströmten Flusssohle - Einleitung. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 155156. ENGELHARDT, C., GOLOSOV, S., CASPER, P., HUPFER, M., KIRILLIN, G. (2006): Seiche-induced convection in upper sediments. In: RUEDA, F. (ed.): Physical processes in natural waters, 59-68. FISCHER, H., PUSCH, M. (2006): Auswirkungen wasserbaulicher Eingriffe auf das Zoobenthos und die mikrobiellen Stoffumsetzungen. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 264-272. FISCHER, H., PUSCH, M. (2006): Überblick über die untersuchten Flussabschnitte. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 27-29. FISCHER, H., WILCZEK, S. (2006): Bakterien und deren Stoffumsetzungen. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 147-154. FISCHER, H., WILCZEK, S., BRUNKE, M. (2006): Kohlenstoffumsatz. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 191-198. FREYHOF, J., HUCKSTORF, V. (2006): Conservation and management of aquatic genetic resources: a critical checklist of German freshwater fishes. Berichte des IGB, 23, 113-126. GARCIA, X.-F., BRAUNS, M., PUSCH, M. (2006): MakrozoobenthosBesiedlung in unterschiedlichen Buhnenfeldtypen. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 278-285. GESSNER, J., LUDWIG, A., DIEKMANN, M. (2006): Störe: Implikationen für Schutz und Management. Fischer & Teichwirt, 2006, 63-64. 162 GUHR, H., SCHWARTZ, R. (2006): Stoffliche Belastungen. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 19-26. HAMANN, E., NÜTZMANN, G. (2006): Conceptual reactive transport modelling of a sewage water based contamination in an urban groundwater system. In: KOVAR, K., HRKAL, Z.,.BRUTHANS, J. (eds.): Hydrology and Ecology: The groundwater/ecology connection, 203-207. HIRT, U. (2006): Quantifying of tile drainage areas in a catchment as a base for the modelling of water and matter fluxes. In: MOUCHEL, J.-M., BARLES, S. (eds.): Man and river systems. Interactions among Rivers, their watersheds, and the sociosystem, 111-114. HUPFER, M. (2006): Eutrophierungsverminderung durch Gewässertechnologien- Irrweg oder Herausforderung für Wissenschaft und Praxis. 4. Stechlin-Forum, 4, 21-28. KASPRZAK, P., REESE, C., KOSCHEL, R., SCHULZ, M., HAMBARYAN, L., MATHES, J. (2006): Glacial relicts in NE-German lakes: Habitat characteristics of Eurytemora lacustris (Copepoda, Calanoida). Berichte des IGB, 23, 151-160. KIRILLIN, G., GOLOSOV, S., ENGELHARDT, C. (2006): Observation of a cyclonic gyre produced by internal surge in a small deep lake . Berichte des IGB, 23, 55-64. KIRSCHBAUM, F. (2006): Erstmalige Zucht eines Vertreters der Nilhechtgattung Petrocephalus (P. soudanensis) induziert durch Imitation von Hochwasserbedingungen. In: GREVEN, H., RIEHL, R. (eds.): Biologie der Aquarienfische. Tetra Verlag GmbH, Berlin, 65-72. KIRSCHBAUM, F., KIRSCHBAUM, M. (2006): Ablaichen von zwei Messerfischen der Gattung Brachyhopopomus (B. pinnicaudatus, B. brevirostris) im Aquarium induziert durch Imitation von Hochwasserbedingungen. In: GREVEN, H., RIEHL, R. (eds.): Biologie der Aquarienfische. Tetra Verlag GmbH, Berlin, 74-80. KIRSCHBAUM, F., SCHUGARDT, C. (2006): Fortpflanzungsstrategien und entwicklungsbiologische Aspekte bei südamerikanischen Messerfischen (Gymnotiformes) und afrikanischen Nilhechten (Mormyridae) vergleichende Betrachtungen. In: GREVEN, H., RIEHL, R. (eds.): Biologie der Aquarienfische. Tetra Verlag GmbH, Berlin, 81-116. KLEEBERG, A., GELBRECHT, J. (2006): Risikoabschätzung der Belastung der Müggelspree aus exponierten Gleithängen nach MakrophytenEntfernung. Im Auftrag des Landesumweltamtes Brandenburg (LUA), 1-16. KLEEBERG, A., HUPFER, M. (2006): Experimental studies on sediment and phosphorus resuspension in the lowland River Spree, NE Germany. Berichte des IGB, 23, 79-88. KLEEBERG, A., HUPFER, M. (2006): Re- und Immobilisierung von Phosphor unter alternierenden Milieubedingungen. BMBF-Verbundprojekt „Feinsedimentdynamik und Schadstoffmobilität in Fließgewässern" Förderkennzeichen 02WF0469, 1-59. KNAUS, U., WIRTH, M., RENNERT, B., SCHULZ, C. (2006): Einfluss einer partiellen Substitution von Fischöl durch Leinöl und Sojaöl auf das © IGB 2007 163 Wachstum und die Körperzusammensetzung von Zandern (Sander lucioperca, L). Fischerei & Fischmarkt in Mecklenburg-Vorpommern, 6, 39-40. KNAUS, U., WIRTH, M., RENNERT, B., SCHULZ, C. (2006): Einfluss einer partiellen Substitution von Fischöl durch Leinöl und Sojaöl auf das Wachstum und die Körperzusammensetzung von Zandern (Sander lucioperca, L). Fischer & Teichwirt, 57, 174-175. KÖHLER, J. (2006): Einfluss von Talsperren und durchflossenen Seen auf die Wasserqualität im Spreegebiet. In: MÜLLER, D., SCHÖL, A., BERGFELD, T., STRUNCK, Y. (eds.): Staugeregelte Flüsse in Deutschland. 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(2006): Experimental bristle induction in Micractinium (Chlorophyta): an example of interaction between grazer and phytoplankton. Berichte des IGB, 23, 103-112. MEINELT, T. (2006): Betrachtungen zum Wettangeln. Angeln und Fischen, 12, 3. 164 MEINELT, T. (2006): Dorsch - Kapitale sind das Kapital. Kutter & Küste, 21, 64-66. MEINELT, T. (2006): Große Fische müssen geschont werden oder vom Sinn und Unsinn von Höchst- und Mindestmaßen. Fischer & Angler in Sachsen, 3, 80. MEINELT, T. (2006): Große Fische müssen geschont werden oder vom Sinn und Unsinn von Mindestmaßen. Angeln und Fischen, 2, 3. MEINELT, T. (2006): Weidgerechte Angelfischerei. Ethische Betrachtung einer Passion von Franz Menzebach und Armin Göllner, Buchrezension. Angeln und Fischen, 10, 3. MEINELT, T. (2006): Zum Zurücksetzen großer Fische…. Angeln und Fischen, 9, 3. MEINELT, T., ARLINGHAUS, R. (2006): Zur unterschätzten Bedeutung großer Tiere im Fischereimanagement. Angeln und Fischen, 6, 2. MEINELT, T., STÜBER, A., BRÄUNIG, I. (2006): Weitere Ergebnisse bei der Anwendung von Peressigsäure (Wofasteril E400 und Wofasteril E250) zur Bekämpfung von Fischschimmel (Saprolegnia parasitica) - Erste Erfahrungen bei der Erbrütung von Regenbogenforellen. Fischer & Teichwirt, 57, 12-14. MORSCHEID, H., MÄHLMANN, J., HILT, S. (2006): Wiederbesiedlung von Flachseen mit submersen Makrophyten: Entwicklung einer Handlungsanweisung. In: Deutsche Gesellschaft für Limnologie (ed.): Erweiterte Zusammenfassung der DGL-Tagung, 130-133. NÜTZMANN, G., HOLZBECHER, E., WIESE, B. (2006): Inverse modeling tool visual CXTFIT for one-dimensional transport, sorption and degradation processes during bank filtration. In: STUDZINSKI, J., HRYNIEWICZ, O. (eds.): Modeling concepts and decision support in environmental systems. Polish Academy of Sciences, Warsaw, System research, 11-24. OHLBERGER, J., STAAKS, G., HÖLKER, F. (2006): Influence of morphology on swimming costs in fishes . Berichte des IGB, 23, 127-138. PFLUGMACHER, S., PEUTHERT, A., CHAKRABATI, S. (2006): Cyanobacterial toxins and oxidative stress responses in aquatic macrophytes. Berichte des IGB, 23, 31-40. PUSCH, M. (2006): Szenarien und Entscheidungshilfen. In: Pusch, M., Fischer, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 301-310. PUSCH, M., FISCHER, H. (2006): Einleitung. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 1-6. PUSCH, M., FISCHER, H. (2006): Zusammenfassung und Ausblick. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 311-319. PUSCH, M., FISCHER, H. (eds.) (2006): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee Verlag, Berlin. PUSCH, M., FISCHER, H., SCHWARTZ, R. (2006): Synthese der Auswirkungen. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 295-300. © IGB 2007 165 PUSCH, M., SCHWARTZ, R., FISCHER, H. (2006): Prozesse und Biozönosen in den Buhnenfeldern - Einleitung. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 83-86. RESTREPO, G., BRÜGGEMANN, R. (2006): Ranking regions using cluster analysis, Hasse diagram technique and topology. In: VOINOV, A., JAKEMAN, A. J., RIZZOLO, A. E. (eds.): Proceedings of the iEMSs Third Biennial Meeting: "Summit on Environmental Modelling and Software", 1-6. SAUER, W., KRÜGER, A., ENGELHARDT, C. (2006): Artificial vs natural flooding regime of a polder in the Lower Odra Valley: sediments and loads. In: STUDZINSKI, J., HRYNIEWICZ, O. (eds.): Modelling concepts and decision support in environmental systems, 57-68. SCHUGARDT, C., KIRSCHBAUM, F. (2006): Erstmaliges Ablaichen der zwei Nilhechtarten Mormyrus sp. und Marcusenius mento unter Aquarienbedingungen induziert durch Imitation von Hochwasserbedingungen. In: GREVEN, H., RIEHL, R. (eds.): Biologie der Aquarienfische. Tetra Verlag GmbH, Berlin, 159-170. SCHUGARDT, C., KIRSCHBAUM, F. (2006): Fortpflanzung und Entwicklung von Polypterus senegalus. In: GREVEN, H., RIEHL, R. (eds.): Biologie der Aquarienfische. Tetra Verlag GmbH, Berlin, 171-182. SCHWARTZ, R. (2006): Entstehung und Gliederung des Flusslaufs. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 7-14. SCHWARTZ, R., BRUNKE, M., FISCHER, H. (2006): Sedimentdynamik. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 171-173. SCHWARTZ, R., KOZERSKI, H.-P. (2006): Sedimentation in Buhnenfeldern. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 105-117. SUKHODOLOV, A., SUKHODOLOVA, T. (2006): Evolution of mixing layers in turbulent flow over submersible vegetation: field experiments and measurement study. In: FERREIRA, R. L. M., ALVES, E. C. T., LEAL, J. G. A. B., CARDOSO, A. H. (eds.): River Flow 2006. Taylor & Francis/Balkema, London, UK, 1, 525-534. SUKHODOLOV, A., SUKHODOLOVA, T., BUNGARTZ, H. (2006): Turbulence in natural streams. In: STUDZINSKI, J., HRYNIEWICZ, O. (eds.): Modeling concepts and decision support in environmental systems. Polish Academy of Sciences, Warsaw, System research, 41-56. SUKHODOLOVA, T., SUKHODOLOV, A. (2006): Field-scale experiment on the flow dynamics over submerged macrophytes. Berichte des IGB, 23, 6578. SUKHODOLOVA, T., SUKHODOLOV, A., KOZERSKI, H.-P., KÖHLER, J. (2006): Longitudinal dispersion in a lowland river with submersible vegetation. In: FERREIRA, R. L. M., ALVES, E. C. T., LEAL, J. G. A. B., CARDOSO, A. H. (eds.): River Flow 2006. Taylor & Francis/Balkema, London, UK, 1, 631-638. VENOHR, M., BEHRENDT, H. (2006): Nitrogen retention in surface waters: application and inter-comparison of empirical and conceptual models. 166 In: MOUCHEL, J.-M., BARLES, S. (eds.): Man and river systems. Interactions among Rivers, their watersheds, and the sociosystem, 260263. VENOHR, M., BEHRENDT, H. (2006): Spatial distribution of nitrogen emissions and retention and their influence on the resulting load. Berichte des IGB, 23, 141-150. VOIGT, K., BRÜGGEMANN, R. (2006): Information Systems and Databases. In: BRÜGGEMANN, R., CARLSEN, L. (eds.): Partial Order in Environmental Sciences and Chemistry. Springer, Berlin, 328-351. VOIGT, K., BRÜGGEMANN, R. (2006): Method of Evaluation by Order Theory Applied on the Environmental Topic of Data-Availability of Pharmaceutically Active Substances. In: STUDZINSKI, J., HRYNIEWICZ, O. (eds.): Development of Methods and Technologies of Informatics for Process Modeling and Management. Polish Academy of Sciences, Systems Research Institute, Warsaw, 107-120. VOIGT, K., PUDENZ, S., BRÜGGEMANN, R. (2006): ProRank - a Software Tool used for the Evaluation of Environmental Databases. In: VOINOV, A., JAKEMAN, A. J.,.RIZZOLO, A. E. (eds.): Proceedings of the iEMSs Third Biennial Meeting: "Summit on Environmental Modelling and Software", 1-6. WAUER, G., CASPER, P., GONSIORCZYK, T., KOSCHEL, R. (2006): Restaurierung des Tiefwarensees, Mecklenburg-Vorpommern, von 20012005 mit der Fällmittelkombination NaAl(OH)4/Ca(OH)2: Auswirkungen auf die Sedimentbeschaffenheit und interne P-Retention. In: Deutsche Gesellschaft für Linmnologie (ed.): Erweiterte Zusammenfassungen, 109-113. WILCZEK, S. (2006): Extrazelluläre Enzymaktivitäten freier und angehefteter Bakterien. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 79-82. WINKLHÖFER, K., LESZINSKI, M., STEINBERG, C. E. W. (2006): Industriebetriebe an der Oberspree und ihre Auswirkungen auf die biotische Beschaffenheit des Flusses im frühen 20. Jahrhundert. In: FRANK, S., GANDY, M. (eds.): Hydropolis - Wasser und die Stadt der Moderne. Campus, Frankfurt New York, 117-145. WOLTER, C. (2006): Bedeutung von Auen für die Fischfauna und ihre Rolle im ökologischen Monitoring. Dokumentationen zu den WRRLSeminaren der GRÜNEN LIGA, 17-19, 65-69. WOLTER, C. (2006): Die fischökologische Bedeutung von Flussauen und ihre Berücksichtigung bei der fisch-basierten Gewässer-Zustandsbewertung. Artenschutzreport, 19, 45-49. WOLTER, C. (2006): Vorkommen und Verbreitung des Stromgründlings Romanogobio belingi (Slastenenko, 1934) in der unteren Oder. Nationalpark-Jahrbuch Unteres Odertal, 2006, 48-54. WÖRNER, U., BRUNKE, M. (2006): Vertikale Wechselwirkungen zwischen Pelagial und Sediment im Buhnenfeld. In: PUSCH, M., FISCHER, H. (eds.): Stoffdynamik und Habitatstruktur in der Elbe. Weissensee, Berlin, 225232. © IGB 2007 167 4.3 Degrees Abschlüsse 4.3.1 Bachelor and Master Theses Bachelor- und Diplomarbeiten AULHORN, M. (2006): Einfluss eines cynobakteriellen Rohextraktes auf verschiedene Spinatvarietäten: Korrelation von Keimung und Wachstum mit dem antioxidativen Stoffwechsel. Humboldt Universität zu Berlin, 120 S. BAHRTH, C. (2006): Gene expression of superoxide dismutase isoforms in Ceratophyllum demersum after exposure to cyanobacterial toxinsimplications for oxidative stress. Universität Konstanz, 88 S. BEHREND, A. (2006): Einfluss des cyanobakteriellem Toxins Microcystin auf die Proteinexpression in Daphnia magna. Humboldt Universität zu Berlin, 110 S. BOEKHOFF, S. (2006): Sukzession und Diversität von Eubakterien und Pilzen während des Laub-Abbaus im Bodensee-Litoral. Universität Konstanz, 57 S. BRÜCKNER, S. (2006): Characterisation of Actinobacteria populations in lakes of the Mecklenburg-Brandenburg Lake District. Hochschule Bremen, 82 S. FALLER, M. (2006): Möglichkeiten und Grenzen der Erfassung potamaler Fische in großen Strömen mittels nächtlicher Elektrobefischungen. Humboldt-Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, 72 S. FREUDENBERG, P. (2006): Unterschiede zwischen organisierten und nichtorganisierten Anglern im urbanen Raum: Eine sozioökonomische Analyse am Beispiel Berlins. Humboldt-Universität zu Berlin, 76 S. GABEL, F. (2006): Impact of ship-induced waves on benthic invertebrates colonising lake shore habitats - An experimental study. Westfälische Wilhelms-Universität Münster, 70 S. HALLERMANN, J. (2006): Auswirkungen eines simulierten Angelvorgangs auf Mortalität und Wachstum von untermaßigen Zandern (Sander lucioperca): die Rolle der Luftexposition. Humboldt-Universität zu Berlin, 53 S. HÜHN, D. (2006): Letale und subletale Auswirkungen von Fangen-undZurücksetzen: Meta-Analyse verfügbarer Literatur und Empfehlungen für das angelfischereiliche Management in Deutschland. HumboldtUniversität zu Berlin, 92 S. JAROSCH, A. (2006): Oxidativer Stress in Cyanobakterien in Daphnia magna: Vergleich der enzymatischen Reaktion mit deren Regulation auf Genebene. Humboldt-Universität zu Berlin, 120 S. JÄHRLING R. (2006): Habitat choice and activity patterns of juvenile eastern freshwater cod (Maccullochella ikei) in an artificial environment. Humboldt-Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, 77 S. 168 MÜLLER, M. (2006): Metabolismus von PCB52 im Nematoden Caenorhabditis elegans und Charakterisierung der dabei induzierten Glutathion S-Transferase. Freie Universität Berlin, 99 S. NEUMANN, F. (2006): Diagenetische Veränderungen partikulärer Phosphorbindungsformen in Seesedimenten unter dem Einfluss von Makrozoobenthos. Universität Potsdam, 78 S. RAPP, T. (2006): Toxische Wirkung von Konservierungsmitteln in Angelfuttermitteln: der Einfluss von Benzoesäure und Kaliumsorbat auf die Eientwicklung beim Zebrabärbling (Danio rerio). HumboldtUniversität zu Berlin, 84 S. SCHOMAKER, C. (2006): Vergleichende Erfassung und Bewertung der Fischgemeinschaftsstruktur in abgetrennten und temporär angeschlossenen Auegewässern des Nationalparks "Unteres Odertal". Humboldt-Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, 87 S. WEISHEIT, C. (2006): Konditionierung von Karpfen (Cyprinus carpio) durch Huminstoffe verschiedener Herkunft. Humboldt-Universität zu Berlin, 92 S. 4.3.2 PhD Theses Doktorarbeiten ALLGAIER, M. (2006): Diversität und Dynamik von Bakteriengemeinschaften in vier ausgewählten Seen der Mecklenburgischen Seenplatte. Universität Oldenburg, 132 S. BLANK, B. (2006): Qualitative und quantitative Charakterisierung des Nitratabbaus im oberflächennahen Grundwasser des SchaugrabenEinzugsgebietes. Humboldt Universität zu Berlin, 146 S. GRESKOWIAK, J. (2006): Reactive transport processes in artificial recharged aquifers - field and modelling studies. Humboldt Universität zu Berlin, 131 S. MEYER, V. (2006): Die Bedeutung von Ciliaten für die Juvenilentwicklung und reproduktion von Copepoden sowie ihre trophischen Interaktionen im Tiefenchlorophyllmaximum eines mesotrophen Sees. IGB, 1-165 S. SCHULZE, T. (2006): Changes in structure and function of the fish community in a mesotrophic lake ecosystem after stocking a non-native top predator. Universität Potsdam, Institut für Biochemie und Biologie, 140 S. SENADEERA, K. P. G. W. (2006): Effects of catchment characteristics and land use practices on water quality of Kotmale, Victoria, Randenigala and Rantambe reservoirs using GIS. University of Jayewardenepura, Sri Lanka, 402 S. VENOHR, M. (2006): Modellierung der Einflüsse von Temperatur, Abfluss und Hydromorphologie auf die Stickstoffretention in Flusssystemen. Mathematisch-Naturwissenschaftliche Fakultät II der HumboldtUniversität zu Berlin, 193 S. © IGB 2007 169 WAUER, G. (2006): Der Einfluss von Fällmittelkombinationen auf die PRetention in Sedimenten geschichteter Seen. Humboldt-Universität zu Berlin, 123 S. WIESE, B. (2006): Spatially and temporally scaled inverse hydraulic modelling, multi-tracer transport modelling, and interaction with geochemical processes at a highly transient bank filtration site. Humboldt Universität zu Berlin, 195 S. ZIPPEL, M. (2006): Modellgestützte Bilanzierung der unterirdischen Wasserressourcen Berlins - die Grundwassersituation im weiteren Einzugsgebiet des Müggelsees. Freie Universität Berlin, 156 S. 4.3.3 Pre-Professional Theses Habilitationen HILT, S. (2006): Toleranz und Leistung aquatischer Makrophyten in nährstoffreichen Gewässern. Humboldt-Universität zu Berlin, 47 S. 170 4.4 Lectures at Universities Vorlesungen an Universitäten ADRIAN, R.: - Freie Universität Berlin, Vom Experiment über die Auswertung zur Publikation, 3 SWS (WS) ARLINGHAUS, R.: - Humboldt-Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, Management of Fish Communities, 4 SWS (WS 2005/2006) CASPER, P., GROSSART, H.-P.: - Humboldt-Universität zu Berlin, Mikrobiologisch-limnologisches Praktikum, 4 SWS (SS 2006) - Technische Universität Dresden, Mikrobiologisch-limnologisches Praktikum, 2 SWS (SS 2006) FREYHOF, J.: - Universität Potsdam, Ökologie und Diversität der Fische, 1 SWS (SS 2006) - Humboldt-Universität zu Berlin, Versuchsplanung und Auswertung freilandbiologischer Daten, 2 SWS (SS 2006) GELBRECHT, J.: - Humboldt-Universität zu Berlin, Wasserchemie, 4 SWS (WS 2005/2006) GROSSART, H.-P.: - Universität Osnabrück, 1 week course: "Aquatic Microbial Ecology" Field station Eilat in cooperation with K.-H. Altendorf, 2 SWS (WS 2005/2006) - Universität Kalmar, 1 week course: "Impact of viruses on bacteria colonizing aggregates"University of Kalmar, Sweden in cooperation with L. Riemann, 2 SWS (SS 2006) - Universität Oldenburg, Planktology class (2 weeks, including 1 week cruise on board of the RV Heincke), physics, chemistry, marine environmental studies, and biology, 3 SWS (WS 2005/2006) HILT, S.: - Humboldt-Universität zu Berlin, Taxonomisch-ökologisches Praktikum, 4 SWS (SS 2006) HÖLKER, F.: - Universität Bremen, Introduction into system analysis, 1 SWS (WS 2005/2006) - Universität Potsdam, Biodiversität und Ökologie der Fische, 1 SWS (SS 2006) HUPFER, M.: - Humboldt-Universität zu Berlin, Biogeochemische Stoffkreisläufe in Seen, 2 SWS (WS 2005/2006) KIRSCHBAUM, F.: - Humboldt-Universität zu Berlin, Systematics and Evolution of Fishes, 4 SWS (WS 2005/2006) © IGB 2007 171 KIRSCHBAUM, F., SCHULZ, C.: - Humboldt-Universität zu Berlin, Biologie, Ökologie und Nutzung tropischer Fischgemeinschaften/ Tropical Fish Communities, 2 SWS (WS 2005/2006) KLOAS, W.: - Humboldt-Universität zu Berlin, Oberseminar: Hormonphysiologie, 1 SWS (WS 2005/2006) - Humboldt-Universität zu Berlin, Vergleichende Endokrinologie, 2 SWS (WS 2005/2006) KNOPF, K.: - Humboldt-Universität zu Berlin, Fish Pathology II (Parasitology), 4 SWS (WS 2005/2006) KOHLMANN, K.: - Humboldt-Universität zu Berlin, Genetics and Breeding of Fishes, 4 SWS (SS 2006) MEHNER, T.: - Technische Universität Dresden, Fischökologie Blockkurs, 2 SWS (WS 2005/2006) MEINELT, T.: - Humboldt-Universität zu Berlin, Environmental stress in fishes, 3 SWS (SS 2006) NÜTZMANN, G.: - Humboldt Universität zu Berlin, Hydrologische Modelle I, 2 SWS (WS 2005/2006) - Humboldt-Universität zu Berlin, Hydrologische Modelle, 2 SWS (WS 2005/2006) - Humboldt Universität zu Berlin, Einführung in die Hydrologie, 2 SWS (SS 2006) PFLUGMACHER, S.: - Humboldt-Universität zu Berlin, Biochemische Regulation im aquatischen Ökosystem, 2 SWS (WS 2005/2006) - Humboldt-Universität zu Berlin, Biochemische Regulation im aquatischen Ökosystem (Fachkurs), 4 SWS (WS 2005/2006) - Humboldt-Universität zu Berlin, Biochemische Regulation im aquatischen Ökosystem (Fachkurs), 2 SWS (WS) - Humboldt-Universität zu Berlin, Biochemische Regulation im aquatischen Ökosystem (Oberseminar), 2 SWS (SS) PUSCH, M.: - Universität Potsdam, Aquatische Ökologie II - Fließgewässerökologie, 2 SWS (SS 2006) RENNERT, B.: - Humboldt-Universität zu Berlin, Special Aquaculture, 2 SWS (WS 2005/2006) - Humboldt-Universität zu Berlin, Special Aquaculture, 2 SWS (WS 2005/2006) WIEDNER, C., DITTMANN, E.: - Humboldt Universität zu Berlin, Molekulare Ökologie Praktikum, 4 SWS (SS 2006) 172 WIEGAND, C.: - Humboldt-Universität zu Berlin, Methoden der BiochemischMolekularen Ökotoxikologie, 2 SWS (WS 2005/2006) - Humboldt-Universität zu Berlin, Aktuelle Fragen der Ökotoxikologie, 2 SWS (WS 2005/2006) - Humboldt-Universität zu Berlin, Biochemisch Molekulare Ökotoxikologie, 2 SWS (SS 2006) - Humbolt-Universität zu Berlin, Biochemische Ökotoxikologie, Laborund Freilanduntersuchungen (Fachkurs), 4 SWS (SS 2006) WILHELM, S.: - Universität Potsdam, Tutorium zur Ökologie II, 1 SWS (WS 2005/2006) © IGB 2007 173 4.5 Memberships in Scientific or Editorial Boards Verantwortliche Positionen in Fachgesellschaften oder Gremien ARLINGHAUS, ROBERT: - Fisheries Management and Ecology, Editorial Board Member - European Inland Fisheries Advisory Commission of the FAO, Working Party on Recreational Fisheries, Head - European Inland Fisheries Advisory Commission of the FAO, Subcommission IV Social and Economic Issues, Rapporteur - European Anglers Alliance, Scientific Advisory Committee CASPER, PETER: - International Journal of Lakes & Rivers, Editorial Board Member - Beiträge zur angewandten Gewässerökologie Norddeutschlands, Editorial Board Member GESSNER, JÖRN: - World Sturgeon Conservation Society, Board of Directors, Secretary General - Gesellschaft zur Rettung des Störs - Society to Save the Sturgeon (Acipenser sturio L.) e.V., Vorstandsmitglied - International Sturgeon Research Centre, Malaspina University College, Scientific Committee, Member - ICES Working Group on International Transfers of Marine Organisms, Member - HELCOM Habitat, PG Restoration of Baltic Sturgeon, Chairman GROSSART, HANS-PETER: - Aquatic Microbial Ecology, Reviewing Editor - Scientific World (online publisher), Editorial Board Member HILT, SABINE: - DGL-Arbeitskreis Flachseen, Leitung HUPFER, MICHAEL: - Limnologica, Advisory Board Member - Lake Restoration Center, University of Southern Denmark, Advisory Board Member KASPRZAK, PETER: - International Review of Hydrobiology, Advisory Board Member - Limnologica, Advisory Board Member - Präsidium der Deutschen Gesellschaft für Limnologie (DGL), Beisitzer KIRSCHBAUM, FRANK: - Aqua Geographia, Advisory Board Member - Zeitschrift für Fischkunde, Advisory Board Member - Journal of Ichthyology and Aquatic Biology, Advisory Board Member - Gesellschaft zur Rettung des Störs - Society to Save the Sturgeon (Acipenser sturio L.) e.V., Advisory Board Head - Studiengang Fisheries Science and Aquaculture, Prüfungsausschuss 174 KLOAS, WERNER: - General and Comparative Endocrinology, Associated Editor - Environmental Research, Editorial Board Member - Journal of Applied Ichthyology, Editorial Board Member - OECD ad hoc Expert Group: Endocrine Disruptor Task Force for Amphibians KOHLMANN, KLAUS: - Fachbeirat für Aquatische Genetische Ressourcen, BMVEL, Stellvertretender Vorsitzender - Environmental Biotechnology, Editor KOSCHEL, RAINER: - International Association of Theoretical and Applied Limnology (IVL), Nationaler Repräsentant - Institut für Angewandte Gewässerökologie GmbH, Seddin, Gründungsmitglied und Vorstandsmitglied - Limnologica, Elsevier Verlag, Managing Editor - Beiträge zur angewandten Gewässerökologie Norddeutschlands, CoEditor KRIENITZ, LOTHAR: - Limnologica, Advisory Board Member - Algological Studies, Editorial Board Member - Phycologia, Co-Editor - Süßwasserflora von Mitteleuropa, Co-Editor MEHNER, THOMAS: - Limnologica, Advisory Board Member - ASLO Committee on Education, Committee Member MEINELT, THOMAS: - Präsidium des Deutschen Anglerverbandes e.V. (DAV), Referent für Umwelt und Gewässer - Gemeinsamer Fachbeirat Gewässerökologie des DAV und der Naturfreunde Deutschlands, Sprecher PFLUGMACHER, STEPHAN: - Environmental Toxicology and Chemistry, Editorial Board Member - Journal of Applied Phycology, Editorial Board Member POYNTON, SARAH L.: - Acta Protozoologica, Editorial Board Member - Food and Agriculture Organization of the United Nations, Regional Reviewer for Aquaculture PUSCH, MARTIN: - Annales de Limnologie – International Journal of Limnology, Co-Editor WALZ, NORBERT: - International Review of Hydrobiology, Executive Editor WOLTER, CHRISTIAN: - Landesfischereibeirat Berlin, Vorsitzender © IGB 2007 175 4.6 Projects and grants Projekte und Stipendien EU Projects EU-Projekte BEHRENDT, H.: EUROHARP: Towards European harmonized procedures for quantification of nutrient losses from diffuse sources (FKZ: EVK1CT-2001-00096-Euroharp); 2002-2006. BEHRENDT, H.: Strengthening the Implementation for Nutrient Reduction and Transboundary Cooperation in the Danube River Basin (FKZ: RER/03/G31); 2006-2007. KIRSCHBAUM, F.: CRAFT: Analyse des Genom nach Sexmarkern mittels AFLP (Amplified Fragment-Length Polymorphism) und RAPD (Random Amplification of Polymorphic DNA) (FKZ: Q5CR-200272183 CRAFT); 2003-2006. KLOAS, W.: COMPRENDO: Comparative Research on Endocrine Disrupters (FKZ: ECK1-CT-2002-00129-Comprendo); 2002-2006. KLOAS, W.: EASYRING: Environmental Agent Susceptibility Assessment Utilising Existing and Novel Biomarkers as Rapid Non-Invasive Testing Methods (FKZ: QLK4-CT-2002-02286 Easyring); 2003-2006. KLOAS, W.: EMSG43 Endocrine disrupting effects in fish induced by parasites (FKZ: CEFIC-LRI Grant EMSG43); 2006-2009. KRIENITZ, L.: Potential and risk of mass developments of the cyanobacterium Arthrospira, an important food resource in tropical inland waters (FKZ: UNESCO 1-DE-09); 2005-2006. STAAKS, G.: TECHNEAU: technology enabled universal access to safe water (FKZ: EU contract 018320); 2006-2008. SUKHODOLOV, A.: NATO GRANT ESP.NUKR.EV 982416 (FKZ: ESP.NUKR.EV 982416); 2006 176 DFG Projects DFG-Projekte ADRIAN, R., GERTEN, D. (PIK): Phase shifts within lake plankton communities in response toward climate warming: Implications for the match/mismatch of species interactions (Aquashift) (FKZ: AD 91/12-1); 2004-2007. ARLINGHAUS, R., WOLTER, C.: Adaptive Dynamik und Management gekoppelter sozial-ökologischer Systeme am Beispiel der Angelfischerei (ADAPTFISH); 2006-2009. BUNGARTZ, H., GROSSART, H.-P.: Untersuchungen zum Einfluss der Aggregatbildung in Flüssen auf die Transportdynamik von Schwebstoffen (FKZ: BU 1442/1-1+ 1-2); 2004-2007. GROSSART, H.-P., KRIENITZ, L.: Dynamik von Bakterien-Algen Interaktionen: Ein Schlüssel zum Verständnis von Nährstoffkreisläufen in aquatischen Systemen (FKZ: GR 1540/8-1 + 8-2); 2005-2007. GROSSART, H.-P.: AQUASHIFT Effects of climate variability on interactions between cyanobacteria and associated microheterotrophs-consequences for development of toxic cyanobacterial blooms (FKZ: GR 1540/11-1); 2006-2009. KIRILLIN, G., ENGELHARDT, C., CASPER, P.: Untersuchung der dreidimensionalen Zirkulationsströmung im Stechlinsee (FKZ: KI 853/2-1); 2004-2006. KIRILLIN, G., BEHRENDT, H.: Climatic impact on temperature and mixing regime of polymictic lakes and its consequences for lake ecosystems (FKZ: KI 583/3-1); 2005-2007. KOZERSKI, H.-P.: Systematische Untersuchung der Retentionswirkung von Makrophyten durch Partikelsedimentation im strömenden Wasser (FKZ: KO 1352/6-1 + 6-2); 2004-2006. KRIENITZ, L.: Gattungs- und Artkonzept bei Chlorella und Micractinium (Chlorophyta, Chlorellaceae): Genotyp versus phaenotypischer Variabilität unter dem Einfluss von Kairomonen (FKZ: KR 1262/8-1 + 8-2); 2003-2006. MEHNER, T., FREYHOF, J.: The impact of climate variability on recruitment, life history, and physiology of sympatric pairs of ciscoes (Teleostei: Coregonus spp.) in lakes (FKZ: ME 1686/5-1 + 5-2); 2004-2006. MENZEL, R.: Systematische Untersuchungen zur Xenobiotika- und Huminstoff induzierten Genexpression (FKZ: ME 2056/2-1); 20042006. MENZEL, R.: Systematische Untersuchungen zur Xenobiotika- und Huminstoff induzierten Genexpression im Nematoden Caenorhabitis elegans (FKZ: ME 2056/2-2); 2006-2007. SUKHODOLOV, A.: A Fluid Dynamics Laboratory in the Field: a study on shallow mixing layers at confluent and recirculating river flows under yet simplified conditions (FKZ: SU 405/2-1); 2006-2008 © IGB 2007 177 Federal institution projects Bundesprojekte BEHRENDT, H., KLOAS, W., BRÜGGEMANN, R.: Auswirkungen des Globalen Wandels auf Nähr- und Schadstoffeinträge und Stoffrückhalte im Elbegebiet und auf den ökologischen Zustand der Oberflächengewässer (GLOWA-Elbe II, FKZ: 01LW0313); 2004-2007. BEHRENDT, H.: Quellen der Nährstoffeinträge und –Frachten im Flusseinzugsgebiet der Weichsel (FKZ: DLR, DPF 05/330); 2005-2006. BEHRENDT, H.: Entwicklung eines szenariofähigen Managementtools für Stoffeinträge in Oberflächengewässer im Rahmen der internationalen Berichtspflichten (UBA/Uni Karlsruhe, FKZ: 20524204); 2005-2007. BEHRENDT, H.: Integriertes Wasserressourcen-Management in Zentralasien: Modellregion Mongolei (MoMo) Teilprojekt : Landnutzung und Nährstoffbilanzen (FKZ: 0330762D MoMo); 2006-2009. GELBRECHT, J.: Twinning Prpojekt zu "Capacity Building Environment": Arbeitsplanung und Abrechnungsverfahren (FKZ: TR02/EN/01 Twinning NATURA); 2004-2006 GESSNER, J.: Untersuchung zur Ökologie Atlantischer Störe als Voraussetzung zur Wiederherstellung der ursprünglichen Fischartendiversität großer Fließgewässer (BMBF); 2004-2006. GESSNER, J., KIRSCHBAUM, F.: Maßnahmen zur Arterhaltung und Bestandsaufbau der Atlantischen Störe in Nord- und Ostsee; Wiss. Begleitung "Haltung der Elterntierbestände und versuchsweiser Besatz (BfN/Gesell. Z. Rettung des Störs, e.V. Z1.3-892 11-6/05); 2005-2008. HUPFER, M.: Verbundprojekt Feinsedimentdynamik und Schadstoffmobilität in Fließgewässern, TP 11: Mikrobielle Re-und Immobilisierung von Phosphor unter alternierenden Milieubedingungen (FKZ: 02WF0469); 2004-2006. HUPFER, M.: Entnahme von Sedimentkernen, in situ und Labormessungen (FKZ: Z6-00313 1035); 2006-2007. KIRSCHBAUM, F.: Genetische Populationsstruktur, Zuchtplan u. künstliche Vermehrung einer süßwasseradaptierten Zuchtgruppe des Europäischen Störes (Acipenser sturio) als Voraussetzung einer erfolgreichen Wiedereinbürgerung (0330718 Störe); 2005-2007. KLOAS, W.: Amphibien-Metamorphose-Assay – Validation Phase II (20467454/01 UBA); 2004-2006. KLOAS, W.: Bewertung und Regulation von Umwelthormonen TV 03: Fortsetzung der Validierung des 21-d-Amphibien-Metarmorphose-Assay (FKZ: Z6-97 411-14/41); 2006-2007. PFLUGMACHER, S., WIEGAND, C.: Verbundprojekt: Minimierung der Eutrophierung im Chaosee, China-Provinz Anhui, TP2: Entwicklung umweltbiotechnischer Verfahren (02 WT 0529); 2005-2007. 178 Other projects Andere Projekte ARLINGHAUS, R.: Ermittlung der Aalentnahme durch die Angelfischerei in Binnen-und Küstengewässern von Mecklenburg-Vorpommern (Landesforschungsanstalt für Landwirtschaft und Fischerei Mecklenburg-Vorpommern); 2005-2008. ARLINGHAUS, R.: Vorbereitung, Methodik und Auswertung der Anglerbefragung für die Region Nordwestmecklenburg und die Auswertung der Partnerregionen im Interreg-III b-Projekt Sustainable management of angling tourism in Natura 2000 and other sensitive areas (LMS, Befragung/Ausw.); 2006-2007. BEHRENDT, H.; Analyse von Agrar- und Umweltmaßnahmen im Bereich des landwirtschaftlichen Gewässerschutzes vor dem Hintergrund der EGWasserrahmenrichtlinie in der Flussgebietseinheit Weser (Bundesforschungsanstalt für Landwirtschaft/Institut für ländliche Räume); 2005-2008. BEHRENDT, H., KÖHLER, J.: Entwicklung eines Bewertungsverfahrens für Phytoplankton in Fließgewässern (LAWA-Projekt-Nr. O11.06); 20032006. BEHRENDT, H.: Erarbeitung eines Modellprototyps für die Berechnung von Nährstoffeinträgen auf der Basis einer neuen Gebietsuntergliederung und Mitarbeit bei der Modellentwicklung für ein Eintragsmodell für prioritäre Stoffe (Univ. Karlsruhe); 2006-2007. GELBRECHT, J.: Pilotprojekt Altarmanschluss und Renaturierung der Müggelspree; Vertrag über das Monitoring, (LUA Brandenburg); 2005-2007. GELBRECHT, J.: Untersuchung der Phosphorfreisetzung aus wiedervernässten Mooren im Peenetal (Land Mecklenburg – Vorpommern); 2003-2007. GESSNER, J.: Anschaffung und Transport eines Elterntierbestandes an Stören im Rahmen der Wiedereinbürgerung in der Oder (Land Brandenburg); 2004-2006. GESSNER, J: Aufbau eines Elterntierbestandes des baltischen Störs A. Oxyrinchus (M-0523-U); 2006-2007. GINZEL, G.: Wiederbewässerung der Rieselfelder um Hobrechtsfelde (Berliner Forsten); 2003-2006. HORNER, C., NÜTZMANN, G.: Erarbeitung von Planungsgrundlagen für die Pilotanlage Machnow - Hydraulisch-reaktive Modellierung PrognosePlanungsmodell BIOXWAND (BWB, 45203925); 2005-2006. KASPRZAK, P.: Verbesserung der Wasserqualität in thermisch geschichteten Hartwasserseen des NO-deutschen Tieflandes: Die Bedeutung von äußerer Nährstoffbelastung und pelagischer Nahrungskettenstruktur für Sedimentation und Phosphorfreisetzung aus dem Sediment (DBU 2005/801); 2006-2009. KLOAS, W.: Untersuchung von Wasserproben auf endokrine Stoffe und Auswertung der Analyseergebnisse im Rahmen der Risikoanalyse der UVS (Berliner Forsten); 2004-2006. © IGB 2007 179 KLOAS, W.: Wiederbewässerung der Rieselfelder um Hobrechtsfelde, Untersuchungen für Sedimente, Grund-u.Oberflächenwasser (Sedimentuntersuchung); 2004-2006 KNOPF, K: Beschreibung der Auswirkungen von Futtermittelzulagen auf den physiologischen Zustand von Zierfischen (Tetra GmbH); 2003-2006. KNOPF, K.: Prüfung von mindestens 5 Fischarten auf ihre Eignung als Modell eines Zierfisches zur Wirksamkeitsuntersuchung potentiell immunstimulierender Futterzusätze (Tetra GmbH); 2006-2007. KÖHLER, J., MISCHKE, U.: Mitarbeit im Praxistest Bewertungsverfahren mittels Phytoplankton für Seen zur Umsetzung der EUWasserrahmenrichtlinie (BTU Cottbus); 2005-2006. KÖHLER, J.: Phytoplanktonanalysen von bayrischen Seen zur Weiterentwicklung des für die EU-WRRL vorgeschlagenen Bewertungssystems (Bayr. Seen); 2005-2006 KÖHLER, J., MISCHKE, U.: Überarbeitung der Taxaliste der Gewässerorganismen in Deutschland (Bayrisches Landesamt für Wasserwirtschaft); 2005-2006. KÖHLER, J.: Umsetzung der Wasserrahmenrichtlinie – Praxistest Bayern: Auszählung und Bewertung von Phytoplanktonproben aus bayrischen Fließgewässern (Freistaat Bayern); 2004-2006 KOHLMANN, K.: Durchführung von Untersuchungen zurückkehrender Laichfische des Atlantischen Lachses (Salmo salar) auf genetische Marker (Freistaat Sachsen / Sächsische Landesanstalt für Landwirtschaft); 2003-2006. KOHLMANN, K.: Genetische Charakterisierung rückkehrender Laichfische des Altantischen Lachses (Salmo salar) auf der Basis von vier Mikrosatelliten-Loci (Institut für Binnenfischerei Potsdam-Saccrow); 2004-2007. KOSCHEL, R.: Erarbeitung der Machbarkeitsstudie für den Melzer See unter besonderer Berücksichtigung der Nachhaltigkeit der Restaurierungsmaßnahme Tiefwarensee (Stadt Waren/Müritz); 20062007. KOSCHEL, R., MEHNER, T.: Ganzheitlicher Gewässerschutz: Restaurierung Tiefwarensee (Stadt Waren/ Land Mecklenburg – Vorpommern); 2001-2006. KOSCHEL, R.: Ganzheitlicher Gewässerschutz Tollensesee: a) Wassergüte des Tollensesees und seiner Hauptzuflüsse, b) Limnologische Zustandsanalyse und Machbarkeitsstudie zur Sanierung und Restaurierung des Wanzkaer Sees (Land Mecklenburg – Vorpommern); 1995-2007. KOSCHEL, R.: Untersuchungen zur Nachhaltigkeit der Maßnahme künstliche Calcitfällung und Tiefenwasserbelüftung im Schmalen Luzin (Pilotanlage) (Land Mecklenburg – Vorpommern); 1997-2007. LUTZ, I., KLOAS, W.: Response of larval Xenopus laevis to 17-ß Estradiol (E2): Assessment of development, time to metamorphosis, and gonodal morphology (Syngenta TO 14017-04); 2004-2007. 180 MEHNER, T., FREYHOF, J.: Genetische Charakterisierung existierender Populationen der Kleinen und Großen Maräne (Coregonus spp.) in Seen Schleswig-Holsteins (Land Schleswig-Holstein, Amt für Ländliche Räume Kiel); 2005-2006. MEINELT, T.: Fischei-Test Zebrabärblinge (Fischerei-Test); 2003-2007 MEINELT, T.: Peressigsäure (Wofasteril) als alternatives Therapeutikum gegen Ektoparasiten (Schreiner-Stiftung); 2005-2006. MENZEL, R.: Untersuchung von Flusswassersedimenten (Elbe, Rhein, Donau) auf toxische Wirkung mit einem C.elegans DNA-Microarray (bfg DNA-Microarray); 2006. MISCHKE, U.: Analyse und Bewertung von bayrischen Fließgewässern zur Weiterentwicklung des für die EU-WRRL vorgeschlagenen Bewertungssystems Phytoplankton (Bayr. LA für Umwelt); 2006-2007. PUSCH, M.: Gutachten: Wissenschaftliche Begleitung des DBU-Projekts "Erhaltung von Habitaten der Kleinen Flussmuschel (Unio crassus) im Biosphärenreservat Spreewald durch Einrichtung von Borstenpässen (Landesumweltamt Brandenburg); 2005-2006. PUSCH, M.: Praxistest zur Bewertung von Phytoplankton, Makrophyten und Makrozoobenthos in fünf Berliner Seen im Rahmen der Umsetzung der EU-WRRL (VIII E22/11); 2006. WIEDNER, C.: Cylindrospermopsis raciborskii und Cylindrospermopsin in Gewässern der Berliner Region (Kompetenzzentrum Wasser Berlin); 2004-2007. WIEDNER, C.: Neo-Cyanobakterien und Neo-Toxine in Berliner und Brandenburger Gewässern (Kompetenzzentrum Wasser Berlin); 2005-2007. WOLTER, C.: Bestandserhebung der Fischfauna, Bewertung und Erstellung fischökologischer Referenzzönosen von ausgewählten Fließgewässern Brandenburgs (IfB, Referenzzönosen); 2006. WOLTER, C.: Ermittlung des fischereilich begründeten MindestWasserabflusses in großen Tieflandflüssen am Beispiel der Havel (Fischereigenossenschaft „Havel“); 2005-2008. WOLTER, C.: Fischerfassung in ausgewählten BundeswasserstraßenAbschnitten (SenVerw. Fischerf.); 2006. WOLTER, C.: Untersuchung des Laichgeschehens auf dem Fischlaichplatz "Westlicher Abzugsgraben" bei der Zitadelle Spandau sowie Abgrenzung der Bedeutung dieses Laichplatzes mit solchen im Wehrauslaufbereich der Schleuse Charlottenburg sowie solchen in den Tiefwerder Gräben (Fischereiamt Berlin); 2005-2006. © IGB 2007 181 Grants Stipendien ALLGAIER, M.: Zeitliche und räumliche Variabilität innerhalb der Bakteriengemeinschaft in Seen des Rheinsberger Seengebietes; supervisor: GROSSART, H.-P.: 2004-2006 (Stiftung des Deutschen Volkes). BAUER, N.: Allelopathische Wechselwirkungen zwischen Makrophyten und Phytoplanktonarten; supervisor: HILT, S.: 2005-2008 (Freie Universität Berlin, NaFöG). BRAUNS, M.: Erarbeitung eines Verfahrens zur ökologischen Bewertung von Seeufern; supervisor: WALZ, N.: 2005-2006 (FAZIT-Stiftung) CONTARDO, V.: Einfluss veränderter Wassereintrittspfade auf aquatische Organismen anhand ökotoxikologischer Kenngrößen; supervisor: WIEGAND, C.: 2005-2008 (Graduiertenkolleg Stadtökologie). FARD, M.: Wirt-Parasiten-Beziehungen in Diplomonaden Flagellaten bei wirtschaftlich wichtigen Süßwasserfischen; supervisor: KLOAS, W.: 2004-2006 (Humboldt-Universität zu Berlin, NaFöG). FERNANDES, M.: Identifizierung der Emission von Treibhausgasen über die Grenzfläche Wasser-Athmosphäre geschichteter Seen in Nordostdeutschland; supervisor: CASPER, P.: 2005-2006 (Leonardo-daVinci-Stipendium, EU). GRIGUTYTE, R.: Oxidativer Stress in der Characee 'Nitellopsis obtusa' durch Laubblattinhaltsstoffe - physiologische und ökologische Auswirkung; supervisor: PFLUGMACHER, S.: 2005-2008 (Deutsche Bundesstiftung Umwelt). HAMANN, E.: Modellgestützte Untersuchung des Stofftransports im Grundwasser eines urbanen Ballungsraumes unter besonderer Berücksichtigung veränderter Wassernutzung; supervisor: NÜTZMANN, G.: 2005-2008 (Humboldt-Universität zu Berlin, Deutsche Forschungsgemeinschaft). HILT, S.: Ökologische Relevanz allelopathischer Effekte submerser Makrophyten auf Phytoplankton und Phytobenthos; supervisor: WALZ, N.: 2003-2006 (Humboldt-Universität zu Berlin, Berliner Programm zur Förderung der Chancengleichheit von Frauen in Forschung und Lehre). HUTALLE, K.: Diversität und Dynamik der Bakteriengemeinschaften in ausgewählten Seen der Mecklenburger Seenplatte; supervisor: GROSSART, H.-P.: 2004-2007 (DAAD). KAMARA, S.: Effects of Natural organic matter (NOM) on photosynthetic activity, pigment pattern and antioxidant status of the aquatic macrophytes 'Ceratophyllum demersum' and 'Lemna minor'; supervisors: PFLUGMACHER, S.: 2005-2009 (DAAD). LASKOV, C.: Einfluss submerser Makrophyten auf geochemische Prozesse im Sediment eutropher wiederbesiedelter Flachseen; supervisor: HUPFER, M.: 2004-2006 (Humboldt-Universität zu Berlin, Berliner Programm zur Förderung der Chancengleichheit von Frauen in Forschung und Lehre). 182 NEUMANN, N.: Parasiten als Stressoren und die Auswirkungen von Stress auf die Immunantwort bei Fischen; supervisor: KLOAS, W.: 2004-2006 (Humboldt-Universität zu Berlin, NaFöG). OGUNJI, J.O.: Evaluation of Housefly Maggot Meal as an alternative protein source for tilapia (Oreochromis niloticus); supervisor: KIRSCHBAUM, F. : 2005-2006 (AvHumboldtstiftg., Georg-Forster-Stip.) OSMAN, A.: Der Einfluss von Schwermetallen auf die molekularen und morphologischen Veränderungen im Embryo- und Larvenstadium des afrikanischen Welses; supervisor: KIRSCHBAUM, F.: 2004-2006 (Ägyptische Regierung). PEUTHERT, A.: Physiologische Reaktion von Alfa Alfa auf Exposition mit cyanobakteriellen Toxinen; supervisor: PFLUGMACHER, S.: 2005-2008 (Freie Universität Berlin, NaFöG). RYCHLA, A.: Verbesserung der Wasserqualität in thermisch geschichteten Seen; supervisor: KOSCHEL, R.: 2006-2007 (Deutsche Bundesstiftung Umwelt). SERGELEN, G.: Trophic state, classification and management of Mongolian lakes; supervisor: KOSCHEL, R.: 2006-2007 (DAAD). © IGB 2007 183 4.7 Summary Gesamtübersicht Number 4.1 Peer-reviewed papers in international journals 4.2 Non-reviewed papers, books, book chapters and reports 4.3.1 Master Theses 122 87 17 4.3.2 PhD Theses 7 4.3.3 Pre-Professional Theses 1 4.4 Lectures at Universities University Humboldt-Universität zu Berlin 4.6 Number of IGB lecturers 16 Freie Universität Berlin 1 Universität Bremen 1 Technische Universität Dresden 2 Universität Oldenburg 1 Universität Osnabrück 1 Universität Potsdam 4 University of Kalmar 1 Projects* € in 2006 EU-projects 136.200 DFG-projects 454.700 Federal institution projects 941.400 Other 977.600 Total 2.509.900 * incl. fremdverwaltete Mittel 184 4.8 List of published IGB reports Liste der bisher veröffentlichten Berichte des IGB Hrsg.: IGB, Berlin. ISSN 1432-508X © IGB 2007 Heft 1 Behrendt, H. & Opitz, D. Ableitung einer Klassifikation für Gewässergüte von planktondominierten Fließgewässern und Flussseen im Berliner Raum und güteklassenbezogene Zielvorgaben zur Nährstoffreduzierung im Berliner Gewässersystem. 1996. 91 S. Heft 2 Gelbrecht, J. et al. Stoffeinträge in Oberflächengewässer und Stoffumsetzungsprozesse in Fließgewässern im Einzugsgebiet der Unteren Spree als Grundlage für Sanierungskonzepte. 1996. 148 S. (vergriffen) Heft 3 Prochnow, D. et al. Schweb- und Schadstoffe der unteren Spree 1994-1996, Modellierung und Simulation des dynamischen Verhaltens von Schwebstoffen in eutrophen Fließgewässern. 1997. 127 S. Heft 4 Jahresforschungsbericht 1996. 1997. 289 S. Heft 5 Jahresforschungsbericht 1997. 1998. 166 S. Heft 6 Sonderheft I Proceedings of the Workshop on Order Theoretical Tools in Environmental th Sciences, held on November, 16 , 1998 in Berlin. 1998. 117 S. Heft 7 Sonderheft II Zusammenfassungen der Beiträge des 13. Treffens deutschsprachiger DiatomologInnen mit internationaler Beteiligung vom 25. bis 28. März 1999. 1999. 208 S.: mit CD. Heft 8 Jahresforschungsbericht 1998. 1999. 208 S.: mit CD. Heft 9 Ausgewählte Forschungsergebnisse aus dem IGB zum Themenkreis „Einfluss von Eingzugsgebietscharakteristika auf die Wasserbeschaffenheit von Oberflächengewässern in Brandenburg. 1999. 170 S. Heft 10 Annual Report 1999. 2000. 234 S. Heft 11 Pusch, M. et al. Ökologisch begründetes Bewirtschaftungskonzept für die Spree unter dem Aspekt der bergbaubedingten Durchflussreduktion. 2001. 244 S. 185 186 Heft 12 Sonderheft III Casper, P., et al. Stechlinsee-Bibliographie. 2001. 85 S. Heft 13 Annual Report. 2001. 238 S. Heft 14 Pudenz, S. et al. Proceedings of the Workshop on Order Theoretical Tools in Environmental Science and Decision Systems, held on November 6 th -7 th 2001 in Berlin. 2001. 224 S. Heft 15 Annual Report 2001. 2002. Internet: www.igb-berlin.de. [Erschienen nur als CD-ROM.] Heft 16 Schauser, I. et al. Seeinterne Maßnahmen zur Beeinflussung des Phosphor-Haushaltes eutrophierter Seen. Leitfaden zur Auswahl eines geeigneten Verfahrens. 2003. 106 S.: mit CD-ROM. Heft 17 Annual Report 2002. 2003. 127 S. Heft 18 Arlinghaus, R. Angelfischerei in Deutschland – eine sozialökonomische Analyse. 2004. 160 S. Heft 19 Pusch, M. et al. Die Elbe – Gewässerökologische Bedeutung von Flussbettstrukturen The River Elbe – ecological importance of channel morphology 2004. 304 S. Heft 20 Annual Report 2003. Jahresforschungsbericht 2003. 2004. 206 S. Heft 21 Mehner, T. et al. Entwicklung einer leitbildorientierten Methode zur Bewertung des ökologischen Zustands von Seen anhand der Fischfauna. 2004. 202 S. Heft 22 Annual Report 2004. Jahresforschungsbericht 2004. 2005. 214 S. Heft 23 Annual Report 2005. Jahresforschungsbericht 2005. 2006. 215 S.