The late Paleocene and early Eocene hyperthermal events

Transcription

The late Paleocene and early Eocene hyperthermal events
evidenced by calcareous nannofossils and geochemistry
Dissertation
zur Erlangung des Grades eines
Doktors der Naturwissenschaften
der Fakultät für Geowissenschaften
der Ruhr-Universität Bochum
vorgelegt von
Christian Joachim
aus Hamm (Westfalen)
Bochum
Dezember 2012
Cover photo: SEM image of the PETM-specific nannofossil Discoaster araneus (diameter=15µm).
Die vorliegende Arbeit wurde von der Fakultät für Geowissenschaften der Ruhr-Universität Bochum als
Dissertation zur Erlangung des Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) anerkannt.
1. Gutachter: Prof. Dr. J. Mutterlose
2. Gutachter: Prof. Dr. A. Immenhauser
3. Fachfremder Gutachter: Prof. Dr. C. Pascal
Tag der Disputation: 01.02.2013
Erklärung
Hiermit erkläre ich an Eidesstatt, dass ich die vorliegende Arbeit selbstständig angefertigt sowie die benutzten
Quellen und Hilfsmittel vollständig angegeben habe. Soweit Zitate, Abbildungen und Karten anderer
Werke im Worte oder dem Sinn nach entnommen sind, wurden diese in jedem Einzelfall als Entlehnung
kenntlich gemacht. Diese Dissertation hat noch bei keiner anderen Fakultät oder Hochschule zur Prüfung
vorgelegen und wurde abgesehen von den angegebenen Teilpublikationen noch nicht veröffentlicht. Die
Bestimmungen der Promotionsordnung sind mir bekannt. Die von mir vorgelegte Dissertation ist von Prof.
Dr. Jörg Mutterlose betreut worden.
Bochum Februar 2013
Christian Joachim
TABLE OF CONTENTS
Table of contents
List of figures and tables………………………………………................................................................vi
Abstract...................................................................................................................................................viii
Zusammenfassung.....................................................................................................................................ix
Acknowledgements....................................................................................................................................xi
Chapter I: Introduction.......................................................................................................................0
1.1. Thesis overview..........................................................................................................................1
1.2. Ocean acidification and global warming………….……….......................................................2
1.3. The Paleogene climate evolution and biotic changes..................................................................5
1.4. Calcareous nannofossils and haptophytes..................................................................................9
1.5. Objectives...............................................................................................................................12
Chapter II: Biodiversity and evolution patterns of calcareous nannofossils during the PaleoceneEocene thermal maximum – evidence for surface water acidification?...............................................13
2.1. Introduction............................................................................................................................14
2.2. Section and material................................................................................................................16
2.3. Methods..................................................................................................................................17
2.3.1. Geochemistry.......................................................................................................................17
2.3.2. Calcareous nannofossils........................................................................................................17
2.4. Results.....................................................................................................................................18
2.4.1. Geochemistry.......................................................................................................................18
2.4.2.1. Diversity patterns..............................................................................................................20
2.4.2.2. Nannofossil intervals.........................................................................................................20
2.4.2.3. Statistics............................................................................................................................22
2.5. Discussion...............................................................................................................................22
2.5.1. Excursion floras and PETM conditions................................................................................22
2.5.2. Ocean acidification...............................................................................................................24
2.5.3. Temperature.........................................................................................................................26
2.5.4. Productivity..........................................................................................................................29
2.6. Conclusion..............................................................................................................................29
2.7. Acknowledgements..................................................................................................................30
2.8. Appendix.................................................................................................................................31
Chapter III: Geochemical evidence for environmental perturbations during the Paleocene-Eocene thermal maximum from the equatorial Atlantic................................................................................41
3.1. Introduction............................................................................................................................43
3.2. Material and methods.............................................................................................................44
3.2.1. Section and material.............................................................................................................44
3.2.2. Methods...............................................................................................................................45
TABLE OF CONTENTS
3.3. Results.....................................................................................................................................46
3.3.1. Stable isotope geochemistry..................................................................................................46
3.3.2. Major elements.....................................................................................................................47
3.3.3. Elements related to changes of provenance or weathering.....................................................48
3.3.4. Elements related to bio-productivity.....................................................................................50
3.3.5. Elements affected by diagenesis............................................................................................52
3.4. Discussion...............................................................................................................................52
3.4.1. Stable isotopes......................................................................................................................52
3.4.2. Major elements.....................................................................................................................52
3.4.3. Elements related to changes in provenance or weathering.....................................................54
3.4.4. Elements related to bioproductivity......................................................................................55
3.4.5. Redox-sensitive elements......................................................................................................58
3.5. Conclusion..............................................................................................................................59
3.7. Appendix.................................................................................................................................61
Chapter IV: Temperature related size variation in calcareous nannofossils during the late Paleocene
and early Eocene……………………………………………………………………..…......................64
4.1. Introduction...........................................................................................................................65
4.2. Section and material................................................................................................................67
4.3. Methods..................................................................................................................................67
4.3.1. Geochemistry.......................................................................................................................67
4.4. Results....................................................................................................................................70
4.4.1. Geochemistry.......................................................................................................................70
4.4.2.1. Nannofossil diversity indices.............................................................................................71
4.4.2.2. Floral changes during the hyperthermal events..................................................................73
4.4.3. Coccolithus pelagicus biometry...............................................................................................76
4.4.3.1. Statistical analysis..............................................................................................................76
4.4.3.2. Frequency plots.................................................................................................................79
4.5. Discussion...............................................................................................................................83
4.5.1. Similarities and differences of the ETM nannofossil floras....................................................83
4.5.2. Driving mechanisms of the assemblage and size shifts...........................................................83
4.5.2.1. Productivity.......................................................................................................................84
4.5.2.2. Temperature......................................................................................................................85
4.6. Conclusion..............................................................................................................................86
4.8. Appendix.................................................................................................................................88
TABLE OF CONTENTS
Chapter V: Calcareous nannofossils response to the Paleocene-Eocene thermal maximum at DSDP
Site 401 (Bay of Biscay)...................................................................................................................101
5.1. Introduction........................................................................................................................ .102
5.2. Section and material..............................................................................................................103
5.3. Calcareous nannofossils and paleoenvironmental changes during the PETM.........................103
5.4. Size measurements on Coccolithus pelagicus............................................................................104
5.5. Appendix...............................................................................................................................109
Chapter VI: General conclusion and perspectives………………….................................................115
6.1. Ocean acidification and climate.............................................................................................116
6.2. Evolution..............................................................................................................................118
6.3. Perspective.............................................................................................................................120
Taxonomical index………………....................................................................................................123
References……….........…...............................................................................................................128
Curriculum Vitae.............................................................................................................................148
..................................
List of figures and tables
Fig.1.1. Bjerrum plot, showing how ocean carbonate chemistry and pH are related (modified from
Barker & Ridgwell (2012) and the references therein).
Fig.1.2. Schematic of the dissociation of carbon dioxide in seawater (Barker & Ridgwell, 2012).
Fig.1.3. Carbon release and surface calcite saturation of the PETM and the business-as-usual carbon
emission scenario (Zeebe, 2012) .
Fig.1.4. The “Zachos-curve”, illustrating the ice-free temperatures for the last 65Ma (Zachos et al.,
2008) and the references therein).
Fig. 1.5. Systematics of the Haptophyta and their position within the Eukaryota (Green & Jordan,
1994; Billiard & Inouye, 2004; Sàez et al., 2004; Adl et al., 2005).
Fig. 1.6. Systematics of the Haptophyta and their position within the Eukaryota (Green & Jordan,
1994; Billiard & Inouye, 2004; Sàez et al., 2004; Adl et al., 2005).
Fig.1.7. The haptophyte cell and its features (Jordan, 2012).
Fig.1.8. The bicyclic coccolithophorid life cycle (Geisen et al,, 2002).
Fig.2.1. Palaeogeographical reconstruction (55Ma) and the sampling location.
Fig.2.2. Geochemical and calcareous nannofossil – based features of the PETM.
Fig.2.3. Calcareous nannofossils across the PETM
Fig.2.4. Correlation matrix of the geochemistry and important nannofossil taxa.
Fig.2.5. Calcareous nannofossil record with focus on discoasters.
Fig.2.6. Discoaster diversity, PETM excursion taxa and specific groups of nannofossils.
Fig.2.7. Plate I.
Fig.2.8. Plate II.
Fig.2.9. Plate III.
Fig.2.10. Geochemistry results and diversity indices of calcareous nannofossils.
Fig.2.11. Calcareous nannofossil results from the PETM at Demerara Rise.
vi
LIST OF FIGURES AND TABLES
Fig.3.2. Stable isotopes across the PETM section.
Fig.3.3. Ternary diagram including SiO2, CaO and Al2O3 across the PETM.
Fig.3.4. Terrigenous input, carbonate and opal plotted across the PETM section.
Fig.3.5. Elements related to changes in provenance or weathering.
Fig.3.6. Elements related to bio-productivity.
Fig.3.7. Elements affected by diagenesis.
Fig.3.8. Major components of the different PETM stages recovered from ODP Site 1258C.
Fig.3.9. Major and minor element concentrations and Al-ratios of the different PETM stages.
Fig.3.10. Geochemistry results from the PETM 1258C (Demerara Rise).
Fig.4.2. Sampling interval 1260 A&B, including corephotos, NP-zonation and sample density.
Fig.4.3. Geochemical parameters and nannofossil indices.
Fig.4.4. Calcareous nannofossils across the ETM2 and H2.
Fig.4.5. Calcareous nannofossils across the ETM3.
Fig.4.6. Biometry of Coccolithus pelagicus (length vs. width) and mixture analysis.
Fig.4.7. Size measurement (mean values) vs. δ13Cbulk.
Fig.4.8. Models for δ13Cbulk vs. the mean values of length and width (μm) of the central opening.
Fig.4.9. Correlation matrix of δ13C and the mean values of different size parameters.
Fig.4.10. Correlation matrix for both models and a δ13Cbulk threshold of 0.5‰.
Fig.4.11. Size measurement data of Coccolithus pelagicus including the mode.
Fig.4.12. Model of Coccolithus pelagicus morphology vs. δ13Cbulk.
Fig.4.13. Plate IV.
Fig.4.14. Plate V.
Fig.4.15. Plate VI.
Fig.4.16. Calcareous nannofossil results 1260A.
Fig.4.17. Calcareous nannofossil results 1260B.
Fig.5.2. Calcareous nannofossil record of DSDP Site 401, including derived results.
Fig.5.3. Size measurement data from Coccolithus pelagicus.
Fig.5.4. Frequency plot for the length of Coccolithus pelagicus from DSDP Site 401.
Fig.5.5. Mixture analysis of length and central opening length from Site 401.
Fig.5.6. Plate VII.
Fig.5.7. Plate VIII.
Fig.5.8. Calcareous nannofossil results DSDP Site 401.
Fig.6.1. SEM images of calcareous nannofossils across the PETM 1258C.
Fig.6.2. Model of coccolith morphology from two different sites.
Fig.6.3. Cenozoic record of benthic carbon isotope values (Zachos et al., 2008) and the δ13Cbulk, carbonate
and long-term Coccolithus pelagicus biometry.
vii
ABSTRACT
Abstract
Ocean acidification is currently one of the most discussed scientific topics, included in the debate
of global change induced by mankind. Marine primary producers, providing the basis of the marine
food web, including calcite-producing haptophyte algae, are thought to be strongly influenced
by ocean acidification caused by carbon output from fossil fuel burning. The Paleocene-Eocene
thermal maximum (PETM, 55.5 million years ago) is considered as the closest analogue of global
warming and ocean acidification in earth history compared to the modern world. In this study,
calcareous nannofossils (=fossils of haptophyte algae) from the late Paleocene to early Eocene have
been investigated from an equatorial setting. Calcareous nannofossils of the PETM have been
studied using core material from the equatorial Atlantic, ~0° paleolatitude (Demerara Rise; Leg
207, ODP Site 1258C); the Eocene thermal maximum 2 (ETM2, ~53.7 million years ago) and
Eocene thermal maximum 3 (ETM3, 52 million years ago) have been analysed using samples of
Demerara Rise; Leg 207, ODP Site 1260A,B. Major elements, elements related to changes in
provenance or weathering, elements related to bio-productivity and redox-sensitive elements during
the PETM have been investigated using material from the same site (Demerara Rise; Leg 207,
ODP Site 1258C). In order to quantify the calcareous nannofossil record of the PETM, a North
Atlantic study site (Bay of Biscay, DSDP Site 401, ~44° paleolatitude) has been studied to assess
differences compared to the equatorial site. The three hyperthermal events (PETM, ETM2, ETM3)
are marked by a substantial input of isotopically light carbon into the oceans, superimposed on a
general warming trend and are characterised by increased temperatures and possible surface-water
acidification.
Nannofloras of the PETM can be divided in two groups: small taxa and abnormal developed
discoasters. 1) Small taxa are forms with a large central opening, here regarded as ecophenotypes of
Coccolithus pelagicus. These small ecophenotypes occur in high total abundances during the PETM.
They are interpreted as adaptations to a higher nutrient demand caused by higher metabolic rates
due to higher temperatures and local oligotrophic conditions during the PETM. 2) Abnormal
developed discoasters are not restricted to the PETM, but occur contemporaneus to an elevated
Discoaster diversity (chapter II).
In addition to the nannofossil record, changes of the detrital flux, biological productivity
and paleoredox conditions across the PETM have been addressed by analysing 70 samples for stable
isotopes (δ13Cbulk & δ18Obulk) and major / minor elements. The PETM record of Demerara Rise
shows a pronounced and sharp lithologic change from calcareous chalks (pre-PETM) to laminated,
clay-rich beds (PETM). The typical δ13Cbulk stable isotope pattern anomaly across the PETM is, due
to the low carbonate content, disturbed. K/Al ratios suggest a change in provenance or more intense
weathering in the hinterland. Barium shows a massive decrease of plankton productivity during the
early stage of the event. The Mn/Al ratios and bulk Mn enrichment factors (EF) show a substantial
drop during the PETM onset, followed by a gradual recovery to pre-event values. In contrast to the
depletion of Mn, other typically redox-sensitive elements (e.g. Cr, Co) or element/Al ratios show no
viii
ZUSAMMENFASSUNG
certain changes across the PETM. These results suggest that paleoenvironmental conditions were
probably not oxygen limited (chapter III).
In comparison to the PETM, only minor changes in the composition of nannofossil
assemblage occur during ETM2 and ETM3. The species Coccolithus pelagicus, which provides about
40% of the nannofossil assemblage, is marked by size reductions related to the three hyperthermal
events (PETM, ETM2, ETM3). The largest ecophenotypes of C. pelagicus with a small central
opening, reflecting maximum calcification, occur under normal, non-hyperthermal (cooler)
conditions. Samples with the most negative δ13Cbulk values yield the smallest ecophenotypes with
high total abundance, suggesting a relationship between small ecophenotypes and warm oligotrophic
conditions during hyperthermal events. The elevated temperatures increase the metabolic rate,
while growth is limited by local oligotrophic conditions. Samples with intermediate δ13Cbulk values
show ecophenotypes with medium length and relatively larger central openings. This ecophenotype
is typically found during the ETM2 onset (chapter IV).
Size measurement data from DSDP Site 401, Bay of Biscay, show an uninfluenced size
record (no dwarfing) of C. pelagicus across the PETM. In contrast to Demerara Rise, this site is
influenced by higher continental runoff and high nutrient levels during the event. Therefore, in
this location growth of C. pelagicus is not limited by oligotrophic conditions (chapter V) during the
PETM. The typical PETM “excursion taxa” Discoaster araneus and Coccolithus bownii are absent at
this site.
Zusammenfassung
Ozeanversauerung ist derzeit eines der am intensivst untersuchten Phänomene im Zusammenhang
mit dem vom Menschen verursachten Klimawandel. Primärproduzenten, wie die kalkbildenden
Haptophyten, bilden die Grundlage des marinen Nahrungsnetzes. Diese Primärproduzenten, so
wird vermutet, werden von verschiedenen Faktoren des Klimawandels (Ozeanversauerung und
globale Erwärmung) beeinträchtigt. Das Paläozän/Eozän-Temperaturmaximum (PETM, vor etwa
55,5 Millionen Jahren) wird zur Zeit als das beste erdgeschichtliche Analog zur rezenten globalen
Erwärmung und zu dem sich wandelnden Kohlenstoffkreislauf betrachtet. Kalkige Nannofossilien
des PETMs, des eozänen Temperaturmaximums 2 (ETM2, vor etwa 53,7 Millionen Jahren) und des
eozänen Temperaturmaximums 3 (ETM 3, vor 52 Millionen Jahren) wurden an einem äquatorialen
Standort im Westatlantik (0° Paläobreite) untersucht. Am gleichen Material wurden auch die
geochemischen Signale (δ13Cbulk & δ18Obulk, sowie Röntgenfluoreszenzanalysen) des PETMs erfasst.
Um diesen äquatorialen Standort in eine Relation zu einem Standort in höherer geographischen
Breite bringen, wurde auch ein PETM Bohrkern weiter nördlich in der Bucht von Biskaya (Leg
401, 44°N Paläobreite) mikropaläontologisch untersucht. Alle drei spät paläozänen bis früh eozänen
Temperaturmaxima (PETM, ETM2 und ETM3) sind gekennzeichnet durch einen plötzlichen
Eintrag von isotopisch leichtem Kohlenstoff, einem Erwärmungstrend und Ozeanversauerung.
Die Nannofossil-Vergesellschaftungen des PETM können in zwei Gruppen unterteilt
ix
ZUSAMMENFASSUNG
werden. 1) Kleine Arten – oder Arten mit einer großen zentralen Öffnung. Diese Arten (Coccolithus
minimus und Coccolithus latus), werden hier als Ökophänotypen von Coccolithus pelagicus betrachtet.
Kleine Ökophänotypen kommen in hohen totalen Abundanzen während des PETMs vor und zeigen
keine Deformationen. Deshalb ist es unwahrscheinlich, dass die geringe Größe der Coccolithen
eine Anpassung an Ozeanversauerung des Oberflächenwassers darstellt. Wahrscheinlicher ist eine
Anpassung an die höheren Temperaturen und oligotrophen Bedingungen am Demerara-Rücken.
2) Abnormal oder asymmetrisch entwickelte Discoasteriden sind nicht auf die frühe Phase des
PETMs – also den Horizont mit der stärksten möglichen Ozeanversauerung – beschränkt, sondern
kommen auch in anderen Horizonten mit erhöhter Diversität von Discoaster vor (Kapitel II).
Zusätzlich zu der hochauflösenden Nannofossil-Studie wurden auch Änderungen im
Nährstoffspektrum, der biologischen Produktivität, so wie der Paläoredoxbedingungen während des
PETM vom Demerara-Rücken geochemisch untersucht. Das PETM ist generell von einem scharf
abgegrenzten Wechsel von Kalk (pre-PETM) zu einem laminierten, ton-reichen Horizont (PETM)
geprägt. Die K/Al Verhältnisse deuten entweder auf einen Wechsel in der Herkunft des Materials
oder eine intensivere Verwitterung im Hinterland hin. Barium zeigt einen starken Einbruch in der
biologischen Produktivität während des PETMs an. Das Mn/Al Verhältnis und die Mn Anreicherung
zeigen ebenfalls einen starken Einbruch während des PETMs, gefolgt von einer graduellen
Erholungsphase. Andere redox-sensitive Elemente (z.B. V, Cr, Co) zeigen keine Veränderungen
während des PETMs. Diese Ergebnisse weisen darauf hin, dass die Paläoumweltbedingungen nicht
durch eine Sauerstofflimitierung in den tiefen Wasserschichten geprägt waren (Kapitel III).
Im Vergleich zum PETM sind die anderen beiden hyperthermalen Ereignisse (ETM2 und
ETM3) nur von kleineren Wechseln in der Zusammensetzung ihrer Nannofloren geprägt. Innerhalb
des Taxons Coccolithus pelagicus, welches ca. 40% der gesamten Vergesellschaftung ausmacht,
geschehen jedoch Größen- und/oder Änderungen des Ökophänotypes während der hyperthermalen
Ereignisse. Die Morphologie der Coccolithen zeigt einen nicht-linearen Zusammenhang zur
δ13Cbulk Kurve. Die größten Ökophänotypen mit einer kleinen zentralen Öffnung – und daher auch
mit der größten gesamt-Kalzifizierung – kommen unter “normalen” d.h. nicht-hyperthermalen
(kühleren) Bedingungen vor. In den Proben mit den geringsten δ13Cbulk Werten, also während der
hyperthermalen Ereignisse (PETM, ETM2, ETM3), kommen die kleinsten Ökophänotypen mit
hohen totalen Abundanzen vor, die als Anpassung an höhere Temperaturen und lokale oligotrophe
Bedingungen interpretiert werden. In den Proben mit mittleren δ 13Cbulk Verhältnissen zeigen die
Coccolithen mittlere Gesamtlängen mit einer großen zentralen Öffnung (Kapitel IV).
Die Größenmessungen an C. pelagicus aus dem Datensatz der DSDP Bohrung 401 (Bucht
von Biskaya) zeigen keine Verkleinerung während des PETMs. Im Gegensatz zu den Demerara
Rise Proben ist diese Lokalität stark von einem erhöhten Abfluß vom Festland her geprägt, der viele
Nährstoffe einträgt. Das Größenwachstum von C. pelagicus ist daher an dieser Lokalität nicht durch
oligotrophe Bedingungen limitiert (Kapitel V).
x
ACKNOWLEDGEMENTS
Acknowledgements
First, I would like to thank Prof. Dr. Jörg Mutterlose, Prof. Dr. Adrian Immenhauser, Dr. Peter
Schulte and Dr. Christian Linnert, who initiated this project, for their support and feedback during
the last three years.
Dear Jörg, thank you for providing me the chance to join your working group at the RuhrUniversität Bochum and to work on this most interesting project. I really enjoyed presenting our
work on conferences and getting our work to a real dynamic state. Your door was always open for
discussing results and it was always a pleasure to argue with you.
Dear Peter, thank you for introducing me to the complex field of inorganic geochemistry. Dear
Christian, thank you for always having time for sharing your experiences and enthusiasm with me.
Special thanks to Prof. Dr. Hans-Jürgen Brumsack for discussing the inorganic geochemistry with
me.
Furthermore I would like to thank the BIOACID-community and the Bundesministerium für
Bildung und Forschung for their financial support as well as the “Research School” of the RuhrUniversität Bochum, providing me with a stipend making it possible for me to join the INA
conference in Yamagata (Japan) in 2010 and a research stay in Southampton in 2012.
Special thanks to all people in the palaeontology and sedimentology working groups. I had a great
time with you and really enjoyed being part of this group. Mohammed Ali Hussein, Mohammed
Alqudah, Dr. Cinzia Bottini, Wawrzyniec Chorazy, Dr. Nicolas Christ, Dr. Anthony Druiventak,
Sabine Hahn, Saskia Hesse, René Hoffmann, Stefan Huck, Yasuhiro Iba, Ariane Kujau, Phillip
Meisner, Sebastian Pauly and Jasper Wassenburg. Nathalie Lübke, Carla Möller, Kevin Stevens are
thanked for preparing samples and picking foramaminifers. I am especially grateful to Sabine Sitter
and Cornelia Mell for the help with the administration and organization of this project. Finally
I want to thank Dr. Samantha Gibbs and Sarah O’Dea from the National Oceanography Centre
Southampton, Department of Ocean and Earth Science as well as Dr. André Bornemann from the
University of Leipzig.
Most importantly I would like to thank all my friends, my parents Christel & Franz-Joseph, and
my family for their encouragement, support and friendship.
xi
CHAPTER I
Chapter I
Introduction
0
THESIS OVERWIEW
1.1. Thesis overview
This thesis consists of a general introduction (chapter I) and three manuscripts (chapter II, III, IV),
which have been submitted for publication to international scientific journals (currently under
review) and chapter V, which is a contribution to a manuscript currently in preperation. Chapter
VI is a general conclusion of the thesis. A bibliography of all used quotations and a complete
taxonomic index of all mentioned nannofossil species are given at the end of the thesis.
Chapter I provides the geological and palaeontological background for this PhD study. Topics
adressed include ocean acidification, global warming (1.2), the Paleogene climate evolution and
biotic changes (1.3), calcareous nannofossil taxonomy and ecology. (1.4).
Chapter II “Biodiversity and evolution patterns of calcareous nannofossils during the Paleocene
Eocene thermal maximum – evidence for surface water acidification?” authored by C. Joachim
(CJ), J. Mutterlose and P. Schulte is a high-resolution study of calcareous nannofossils across the
PETM. The data collection and interpretation, as well as the writing and compilation of the figures
of this manuscript have been provided by CJ. The work has been supervised by J. Mutterlose
& P. Schulte who also approved the publication. The manuscript has been submitted to Marine
Micropaleontology.
Chapter III contains a geochemical record of the section already described in chapter II. It is
entitled: “Geochemical evidence for environmental perturbations during the Paleocene-Eocene
thermal maximum from the equatorial Atlantic” authored by CJ, J. Mutterlose, P. Schulte and
H.-J. Brumsack. Besides the isotope record the data was acquired by X-ray fluorescence. The paper
focuses on the distribution pattern of major elements as well as on the detritus-, productivity- and
redox sensitive elements and their palaeoenvironmental interpretation. The geochemical analyses
have been made by H.J. Brumsack (University of Oldenburg). The manuscript, written by CJ, has
been reviewed by the co-authors H.J. Brumsack, P. Schulte and J. Mutterlose. It has been submitted
to Chemical Geology.
Chapter IV “Temperature related size variation in calcareous nannofossils during the late Paleogene
and early Eocene” written by CJ, J. Mutterlose, P. Schulte and C. Linnert. The sampling of the core,
sample preparation and evaluation, including taxonomy, size measurements of the nannofossils and
statistics, as well as the writing of the manuscript is in the responsibility of CJ. The manuscript has
been reviewed by J. Mutterlose. P. Schulte and C. Linnert took part in initiating this PhD project.
The manuscript has been submitted to Marine Micropaleontology.
Chapter V “Implications from the Bay of Biscay” results from a cooperation with André Bornemann
(University of Leipzig). It includes nannofossil results and size measurements on Coccolithus pelagicus
compiled by CJ. The nannofossil data will be a contribution to a manuscript by André Bornemann,
currently in an early stage of preparation.
Chapter VI is a conclusion of the main findings of the thesis and provides a perspective for future
work. It consists of three sub-chapters, namely 6.1 Ocean acidification and climate, 6.2 Evolution
and 6.3 Perspective.
1
CHAPTER I
1.2. Ocean acidification and global warming
The issue of global warming and its “evil twin” ocean acidification have recently become the research
object of a large scientific community. Increasing interest of the mass media and public discussions
of climate change influence nowadays politics, economy and daily life (IPCC, 2012; Schellnhuber
et al., 2012). Ocean acidification is considered as a major threat to marine biodiversity (Kleypas et
al., 1999; Zondervan et al., 2001; Orr et al., 2005; Raven, 2005; Sponberg, 2007). Throughout the
last years several research initiatives on ocean acidification have been started, namely the “European
project on ocean acidification” (EPOCA), the “UK Ocean Acidification Research Programme”
(UKOARP) and the German research program, “Biological Impacts of Ocean Acidification”
(BIOACID), of which this thesis is a subproject. In contrast to the majority of subprojects involved
in the BIOACID research program, this project is not based on experiments with cultured, living
primary producers (nannoplankton). It provides a paleo-perspective on biotic changes caused by
massive short-termed carbon emissions, using fossilised remains of primary producers (calcareous
nannofossils). This PhD study focusses on three relatively short termed warming events in the
Paleocene and Eocene periods. These hyperthermal events include the Paleocene-Eocene thermal
maximum (PETM; 55.5 million years ago), the Eocene thermal maximum 2 (ETM2; ~53.7my
ago) and the Eocene thermal maximum 3 (ETM3; 52my ago). These three hyperthermal events
are potential analogies to the global climatic change observed for the “Anthropocene”, an epoch
defined by rising CO2 and methane concentrations in the atmosphere, coinceeding with the design
of the steam engine in 1784 (Crutzen, 2002). Although similarities exist between these Paleogene
hyperthermals and the current situation, no past event perfectly parallels future projections in
terms of disturbing the balance of ocean carbonate chemistry. The unprecedented rapidity of the
CO2 release, which is currently taking place (Hönisch et al., 2012), is probably quite different from
the situation in the Paleogene. The ocean has captured between 28 and 34% of the anthropogenic
carbon dioxide emitted to the atmosphere between 1980 and 1994 (Sabine et al., 2004; Millero,
2007). The average surface ocean pH, compared to pre-industrial levels (~1850), has already been
decreased by about 0.1 units (Raven, 2005). It has probably not been below 8.1 during the past
2 million years (Hönisch et al., 2009), indicating that HCO3- is the dominant carbonate species
(Barker & Ridgwell, 2012) (Fig. 1.1). If CO2 emissions continue unabated, surface-ocean pH
could decline by approximately 0.7 units by the year 2300 (Zeebe et al., 2008; Zeebe, 2012) and
atmospheric CO2 concentrations will exceed ~2000ppmv (Caldeira &Wickett, 2003; Mikolajewicz
et al., 2007). Ocean conditions to date are already more extreme than those experienced by marine
organisms and ecosystems for at least 20 million years (Pelejero et al., 2010). The timescale of
the anthropogenic carbon input is so short that the natural capacity of the surface reservoirs to
absorb carbon is overwhelmed and the surface-ocean calcite saturation state (Ωc) would drop from
approximately 5.4 to <2 within a few hundred years (Zeebe, 2012). The PETM appears to be the
closest analogon to the predicted future that has so far been identified in the geological record
(Zeebe & Ridgwell, 2011). The calcium ion concentrations were higher in the Paleocene ocean
(Ridgwell & Schmidt, 2010) than those of nowadays oceans. The Ωc in the PETM
2
OCEAN ACIDIFICATION AND GLOBAL WARMING
Fig.1.1: The Bjerrum plot modified from (Barker & Ridgwell, 2012) shows the relationship between pH
and carbonate chemistry (for salinity=35‰, temperature=25°C, pressure=0bar). pH-values of the different
substances are from Bridges & Mattice (1939) and Hoffman et al. (1989).
scenario suggests a decline from 5.5 to ~4 within a few thousand years (Zeebe, 2012). Dissolved CO2
in combination with water produces CO2(aq) and carbonic acid (Eq.1), which rapidly dissociates to
produce bicarbonate ions (Eq.2). The bicarbonate ions can in turn dissociate into carbonate ions.
Both reactions produce protons and therefore influence the pH of the seawater (Eq.3, Fig 1.2).
CO2(aq) + H2O <=> H2CO3 (Eq.1)
H2CO3 <=> HCO3- + H+
(Eq.2)
HCO3- <=> CO32- + H+
(Eq.3)
Concerning ocean acidification, calcite is the more resolution resistant structural form of
CaCO3 compared to aragonite, which is used by corals to build their skeletons (Barker & Ridgwell,
2012). The carbon input had a moderate impact on the surface-water saturation state (Gibbs et
al., 2006; Zeebe et al., 2009; Gibbs et al., 2010). Direct effects of ocean acidification on surface
calcifiers during the PETM may have been limited because of a relatively slow carbon input rate
(Zeebe, 2012).
3
CHAPTER I
Fig.1.2: Illustration of the dissociation of carbon dioxide in seawater and its chemical reactions (Barker &
Ridgwell, 2012). On the lower left the foraminifer Globigerina bulloides is depicted. Foraminifers are one of
the most important calcaerous microfossil groups in earth history.
In contrast to the PETM with an output of 3,000Pg carbon (1Pg=1015g) over a period of
about 6000 years (Zeebe et al., 2009) the proposed “Anthropocene” output of 5,000Pg C will take
place in only 500 years (Zeebe et al., 2008). The ocean acidification event that humans are expected
to cause is unprecedented in the geological past (Zeebe, 2012) (Fig. 1.3). The high speed of carbon
4
OCEAN ACIDIFICATION AND GLOBAL WARMING
release in the “Anthropocene” scenario (500 years) makes the biggest difference to the much slower
PETM scenario (6000 years), because it takes the ocean about 1000 years to transfer CO2 added to
the surface water into the deep sea, where sediments can eventually neutralize the added acid (Kerr,
2010).
Fig. 1.3: The PETM warming versus the „Anthropocene“ warming. Modified from Zeebe et al. (2009);
Zeebe & Ridgwell (2011) and Zeebe (2011), as amended by Zeebe (2012). (a) Business-as-usual carbon
emission scenario as projected for the future (5,000Pg carbon over 500 years (Zeebe et al., 2009)] and as
observed for the PETM [(3,000Pg C over 6,000 years (Zeebe et al., 2009)). The onset of industrialization
has been aligned with the onset of the PETM. (b) Changes in surface-ocean calcite saturation state (ΩC)
simulated with the LOSCAR (Long-term Ocean-atmosphere-Sediment Carbon cycle Reservoir) model
(Zeebe, 2011) in response to the carbon input shown in panel a.
Comparisons between the Cretaceous and the near future (next 500 years), frequently made to
suggest that marine calcification will not be impaired in a future high CO2 world, are invalid (Zeebe
& Ridgwell, 2011). The Mesozoic Era [including the Triassic, Jurassic and Cretaceous; 255-65.5 million
years ago] probably represents the most pronounced period of warmth during the Phanerozoic
[the last 542 million years] (e.g. Barron et al., 1981; Barron, 1983; Hay, 1998). In contrast to the
modern scenario the Cretaceous [145.5-65.5 million years ago] represents a fundamentally different
long-term steady state over 80 million years with different reservoir sizes and controls on carbonate
chemistry (Zeebe & Ridgwell, 2011). For a detailed review of past changes in ocean chemistry see
Zeebe & Ridgwell (2011) and Zeebe (2012).
1.3. The Paleogene climate evolution and biotic changes
After the Chicxulub asteroid impact (65.5 million years ago), triggering the third largest mass
5
CHAPTER I
extinction event [e.g. non-avian dinosaurs, marine and flying reptiles, ammonites, rudists (Fastovsky
& Sheehan 2005), marine primary producers (Sheehan et al., 1996; Aberhan et al., 2007) and a 93%
decrease of calcareous nannofossil species (Bown et al., 2005b)] at the Cretaceous-Paleogene boundary
(Schulte et al., 2010), the early Paleogene provided room for many different taxa to evolve. The
most famous example for the Paleogene evolution is the radiation of placental mammals (Falkowski
et al., 2005).
The recently discovered Latest Danian Event (LDE) may represent another early Paleocene
hyperthermal event (Quillévéré et al., 2008; Ali, 2009; Bernaola et al., 2009; Bornemann et al.,
2009), about 61Ma ago (Speijer, 2003), preceding the PETM. During the Paleocene and early
Eocene, annual mean temperatures rose constantly, culminating in the early Eocene climatic
optimum (EECO) (Zachos et al., 2001) (Fig. 1.4). The EECO is characterised by high atmospheric
CO2 concentrations (Yapp, 2004; Smith et al., 2010), elevated sea surface temperatures (Bijl et al.,
2009) and widespread formation of cherts (Muttoni & Kent, 2007). Bottom water temperatures,
derived from otoliths in the Belgian Basin, show a mean annual temperature of 27.5°C during
the EECO (Vanhove et al., 2011). The late Paleocene - early Eocene hyperthermal events occur
superimposed on a long-term warming trend and are triggered by orbital parameters (Cramer et
al., 2003; Lourens et al., 2005; Nicolo et al., 2007; Galeotti et al., 2010, Sexton et al., 2011). They
occur in the maxima of 405kyr and 100kyr eccentricity cycles (Lourens et al., 2005).
The most intense studied hyperthermal event, the PETM (55.5 Ma) (Kennett & Stott,
1991; Zachos et al., 2005), had an estimated duration of 196ka (Murphy et al., 2010). The PETM
is characterised by a negative carbon isotope excursion (CIE) of ~-3‰ δ13Ccarb (derived from
foraminifera), and a by 3-4°C rise of surface water temperature (Thomas, 1998). The CIE based
on long-chain n-alkanes derived from plant leaf waxes in the central Arctic ocean shows values of
-4.5‰ to -6‰ δ13Cn-alkanes for the same interval. This value may reflect the true isotope values of
atmospheric CO2 in equilibrium with the ocean (Pagani et al., 2006). The initial warming at the
Paleocene-Eocene boundary preceded the CIE (Secord et al., 2010) and is thought to have been a
trigger for the warming of deep ocean currents (Tripati & Elderfield, 2005). These in turn initiated the
melting of methane clathrates or methane “ice” (Bice & Marotzke, 2002), a source for isotopic light
carbon (Dickens et al., 1995; Dickens et al., 1997; Dickens, 2000; Dickens, 2011). The attendant
oxidation of CH4 to CO2 is interpreted to cause climate warming through a greenhouse feedback
(Zachos et al., 2008). Large-scale slope failures, associated with the catastrophic dissociation of
methane, have been reported from the western Atlantic (Katz et al., 1999, 2001). Orbital induced
changes in ocean circulation and intermediate water temperature can trigger the destabilisation of
methane hydrates and explain the decreasing magnitude and increasing frequency of hyperthermal
events during the early Eocene (Lunt et al., 2011). The range of the carbon input suggests a major
alternative source of carbon in addition to any contribution of the methane during the PETM
(Dunkley Jones et al., 2010). Other plausible or additional carbon sources are the decomposition
of soil organic carbon in circum-Arctic and Antarctic continental permafrost (DeConto et al.,
2012) and patterns of surficial carbon redistribution (Sexton et al., 2011).
6
Fig.1.4: The “Zachos curve” from Zachos et al. (2008), modified from Zachos et al. (2001), based on deep-sea benthic foraminiferal oxygen-isotope curve based on records
from DSDP and ODP sites (Zachos et al., 2001) with additional data from Billups et al., 2002; Bohaty & Zachos (2003), and Pälike et al. (2006). The δ18O record
indicates the temperature for the ice-free ocean, preceding the onset of large-scale glaciation on Antarctica, about 35Ma ago (Zachos et al., 2008).
THE PALEOGENE CLIMATE EVOLUTION AND BIOTIC CHANGES
7
CHAPTER I
Sexton et al. (2011) suggest massive DOC storage under anoxic conditions in the abyssal
Southern Ocean, which is ventilated frequently due to astronomical parameters, explaining the
high frequency of less pronounced hyperthermal events during the early Eocene. The release of
carbon to the ocean-atmosphere system led to a rapid lowering of the deep-sea pH and a shoaling
of the carbonate compensation depth (CCD) (e.g. Zachos et al., 2005). The ecological changes
during the PETM are more complex than just changes of the CCD, they also include warming
and oxygen depletion, leading to a benthic foraminifera extinction event (BEE), coinciding with
the PETM onset (Kennett & Stott, 1991; Pak & Miller, 1992; Alegret & Ortiz, 2007; Alegret,
2009; Winguth, 2012). For a detailed review of the PETM see Mc Innerney et al. (2011). The
Eocene thermal maximum 2 (ETM2) or „Elmo“ (=Eocene layer of mysterious origin) horizon,
occurring at ~53.7Ma, is characterised by a negative carbon shift of ~-1.5‰ (Lourens et al., 2005).
The last early Eocene hyperthermal event (~52Ma) is the Eocene thermal maximum 3 (ETM3) or
“X-event” of Röhl et al. (2006) and shows a negative carbon anomaly of ~-1‰ (Röhl et al., 2006).
These two smaller hyperthermal events are thought to share several characteristics with the PETM,
like elevated temperatures, carbonate dissolution and perhaps biotic response (Thomas & Zachos,
2000; Cramer et al., 2003; Zachos et al., 2004; Röhl et al., 2006; Thomas et al., 2006; Nicolo et
al., 2007; Quillévéré et al., 2008; Agnini et al., 2009).
A giant boid snake is reported from the Paleocene continental neotropics, suggesting mean
annual temperatures of 30-34°C (Head et al., 2009). The tropical rainforest during the PETM
was able to persist under elevated temperatures and high levels of atmospheric CO2 (Jaramillo et
al., 2010). The PETM on the continents is characterised by increased mid-latitude tropospheric
humidity and enhanced cycling of carbon through terrestrial ecosystems (Bowen et al., 2004). On
the continents several modern groups of mammals, like Artiodactyla [e.g. deer], Perissodactyla [e.g.
horses] and Primates appear suddenly without any known precursors during the PETM (Gingerich,
2006). Surprisingly, most of the earliest species of these orders are significantly smaller than their
immediate descendants and some contemporary taxa occurring in the PETM appear to be dwarfed
(Gingerich, 2006). The dwarfism of mammals is explained by elevated CO2 levels at the height of
the greenhouse event, affecting plant growth, nutrient storage, digestibility and ultimately, herbivore
growth and reproduction (Tuchman et al., 2002; Gingerich, 2003). The cetaceans [whales], which
originated in the early Eocene, made a gradual transition from terrestrial carnivorous mammals
to aquatic mammals feeding on planctivorous fishes (Gingerich et al., 1983). Plenty of eusocial
insects radiated during the PETM or the early Eocene climatic optimum (EECO), including
corbiculate bees, rhinotermitid termites and modern subfamilies of ants (Formicidae) (Rust et al.,
2010). The amount and diversity of insect damage on angiosperm leaves reaches a maximum during
the PETM, suggesting increased insect herbivory, which is likely a long-term effect of increasing
pCO2 and warming temperatures (Currano et al., 2008). For the floral community, the “plant
community change” hypothesis implies that major changes in the floral composition during the
PETM amplified the CIE, caused by a rapid transition from mixed angiosperm/conifer flora to a
purely angiosperm flora (Smith et al., 2007). The PETM acidification and global warming coincides
8
CALCAREOUS NANNOFOSSILS AND HAPTOPHYTES
with one of the five most substantial metazoan reef crises in the last 500Myr (Kiessling & Simpson,
2011). In contrast to corals, foraminifera and calcareous nannofossils use calcite, not aragonite for
calcification. The rising temperatures led to a stepwise demise of Paleocene coral reefs, giving way to
an unprecedented expansion of larger foraminifera, dominating Tethyan platforms during the early
Eocene (Scheibner & Speijer, 2008).
1.4. Calcareous nannofossils and Haptophytes
Calcareous nannofossils (Greek from nannos = “dwarf ”) are a paraphyletic group [a group of
organisms, not including all descendants of a last common ancestor], including the fossilized, calcitic
remains of haptophyte algae (Coccolithophorids), nannoliths (an extinct group, thought to be
formed by haptophytes or similar eukaryotic protists (Young et al., 1999) [eukaryotic protists are
unicellular organisms containing a nucleus]) and calcitic cysts of dinoflagellates, which belong to the
Alveolata. The Eukaryota are generally subdivided into two divisions, using the number of their
ancestrally possessed flagella (Fig. 1.5).
Fig. 1.5: Systematics of the Haptophyta and their position within the Eukaryota (Green & Jordan,
1994; Billard & Inouye, 2004; Sàez et al., 2004; Adl et al., 2005).
1) Opisthokonts [including fungi and animals] + Amoebozoa, which both ancestrally
possessed a single flagellum, form the first group, called Unikonts. 2) The second group, the Bikonts,
derived from an ancestor who possessed two flagella. The Bikonts include the “super groups” Rhizaria
9
CHAPTER I
[including Foraminifera and “Radiolaria”, both are important index fossils], Archaeplastida [including
plants], Excavata and Chromalveolata (Adl et al., 2005; Parfrey et al., 2006).
Haptophyta are then placed within the group of the Chromalveolata, besides the
Cryptophyceae, Stramenopilata and Alveolata (Adl et al., 2005). The autapomorphy [distinct feature,
known to be a derived trait, unique to a specific terminal group] of the Haptophyta is the haptonema,
an additional spiral filamentous appendage (Fig.1.4) (Bown & Young, 1998; Young & Henriksen,
2003). The haptophytes are therefore a monophyletic [derived from one unique common ancestor
and including all its descendants] group (Jordan, 2009). The Haptophyta include two classes, the
Pavlovophyceae and Prymnesiophyceae (Sàez et al., 2004).
Coccolithophores or coccolithophorids (greek from cocco = berry, kernel litho = stone phora
= to carry), are a paraphyletic group including the orders Isochrysidales and Coccolithales, both
producing calcitic coccoliths. They are placed within the Prymnesiophyceae (Green & Jordan,
1994; Billiard & Inouye, 2004). Additionally, some aragonitic coccoliths are described (Manton
& Oates, 1980; Cros & Fortuno, 2002). Coccoliths are produced, like the cellulose scales of noncalcifying haptophyte taxa, within the Golgi complex (e.g. Pienaar, 1994; Young & Henriksen,
2003; Brownlee & Taylor, 2004) and secreted to the outer layer of the cell, building the coccosphere
(Lohmann, 1902) (Fig. 1.6).
Fig. 1.6: The haptophyte cell and its internal structures (Jordan, 2012).
Coccoliths are one of the main driver of the open ocean organic pump, which removes
CO2 from the atmosphere (Honjo et al., 2008). The accumulation of coccoliths into marine snow
ballasts organic matter that otherwise would not sink to the ocean floor (de Vargas et al., 2007).
Based on gene analysis, haptophytes evolved approximately 824 million years ago (Liu et al., 2010).
10
CALCAREOUS NANNOFOSSILS AND HAPTOPHYTES
Coccoliths first appeared in the late Triassic, about 220 million years ago (Jordan, 2012).
Like all protists, Haptophyta have a biphasic life cycle with a diploid (2n) and a haploid
(n) life stage (Fig.1.7) (Bown & Young, 1998; Geisen et al., 2002; Young & Henriksen, 2003). A
well-known similar complex protist live cycle is the one of Plasmodium causing malaria in humans
(e.g. James & Tate, 1937). The diploid generation of the Coccolithophorids or “heterococcolith
stage” produces coccoliths, which typically occur in the marine fossil record. Heterococcoliths build
complex structures, which consist of strongly modified calcite crystals, arranged in interlocking
cycles (de Vargas et al., 2007). The heterococcolith stage produces 7–204 coccoliths per cell
Fig. 1.7: Schematic illustration of the haptophyte live cycle (of C. leptoporus) modified from Geisen et al.
(2002). Both stages of their lifecycle are depicted, the diploid heterococcolith stage (left) and the haploid
holococcolith stage.
(Knappertsbusch, 1993) building the coccosphere around the cell. The coccolith size is strongly linear
correlated to coccosphere and cell diameter (Henderiks, 2008). Smaller cell sizes in the Oligocene,
relative to the Eocene have been interpreted to potentially reflect the response to increased CO2
limitation associated with the decline in atmospheric CO2 levels across the Eocene-Oligocene
transition (Henderiks & Pagani, 2008). This implies a CO2-related effect on photosynthesis and cell
growth rather than on calcification (Zeebe & Ridgwell, 2012). The possible evolutionary advantages
of calcification in Coccolithophores are still part of a scientific debate, including protection from
physical damage and viral infection, buoyancy regulation, light regulation or chemical buffer
(Braarud et al., 1952; Manton, 1968; Gartner & Bukry, 1969; Young 1994; Bown & Young,
1998; Rost & Riebesell, 2004). In contrast, the haploid, holococcolith stage produces smaller, less
complex, rhombohedral crystals of uniform size (~0.1μm), which are excreted on the edge of the
cell (Rowson, 1986; Kleijne, 1991; Sym & Kawachi, 2000; Young et al., 2003). The holococcoliths
are, due to their size, and simple construction of uniform crystals, rarely preserved in the Mesozoic
11
CHAPTER I
fossil record (Mutterlose et al., 2005). This implicates our study of Coccolithus pelagicus biometry
(chapter IV) is limited to the heterococcolith life stage.
The third group of calcareous nannofossils are the Nannoliths (Haq & Boersma, 1978).
Nannoliths are probably a polyphyletic [not descendants from one common ancestor but of multiple
origin] group of protists (de Vargas & Probert, 2004), thought to be formed by haptophytes, but
probably by a different biomineralisation process to either heterococcoliths or holococcoliths (Young
et al., 1999). Nannoliths include the taxa Braarudosphaeraceae, Ceratolithaceae, Discoasteraceae,
Sphenolithaceae and Triquetrorhabdulaceae and others.
1.5. Objectives
The objectives of this thesis are to describe the sequence of nannofossil patterns (diversity,
abundances, size evolution, origination and extinction patterns) and geochemical properties for
the three late Paleocene - early Eocene thermal maxima (PETM, ETM2, ETM3). The BIOACID
subproject 3.5.2. was integrated in the project 3.5. “Impact of present and past ocean acidification
on metabolism, biomineralisation and biodiversity of pelagic and neritic calcifiers” and entitled:
“Biological response to short-termed ocean acidification events in the past: biodiversity and
evolution patterns of marine primary producers (calcareous nannofossils) during the late Paleocene
– early Eocene”. This thesis focusses on the PETM and whether surface water acidification affected
calcareous nannofossils (chapter II). This has been stated by several authors (e.g. Bybell & SelfTrail, 1995; Jiang & Wise, 2006; Mutterlose et al., 2007; Raffi & De Bernardi, 2008; Raffi et al.,
2009; Self-Trail et al., 2012) and documented by “malformed” calcareous nannofossils restricted to
the PETM. Besides the calcareous nannofossils the concomitant geochemical changes during the
PETM were addressed for the same location (Demerara Rise), with focus on their implications to
palaeoceanography and paleoclimate (chapter III). Part of this geochemical study was also to assess
bio-productivity values independent from the calcareous nannofossil record. This allowes to bridge
the gap, produced by the shallowing carbonate compensation depth during the early stage of the
PETM. The question if ETM2 and ETM3 share the specifications of the PETM, like oligotrophic
warm water conditions is addressed in chapter IV. Size measurements of Coccolithus pelagicus have
been used to determine if the ETMs changes in surface water acidification have an effect on the size
of the coccoliths. The final objective of the thesis was the question if the studied phenomena are
limited to the Equator or also appear in other PETM study sites (DSDP Site 401, Bay of Biscay).
12
CHAPTER II
Chapter II
Biodiversity and evolution patterns of calcareous
nannofossils during the Paleocene-Eocene
thermal maximum
–
evidence for surface water acidification?
13
CHAPTER II
Chapter II: Biodiverstiy and evolution patterns of calcareous nannofossils
during the Paleocene-Eocene thermal maximum - evidence for surface water
acidification?
Christian Joachim a, *, Jörg Mutterlose a & Peter Schulte b
a
Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität Bochum, Universitätsstr. 150,
44801 Bochum, Germany
b
GeoZentrum Nordbayern, Universität Erlangen, Schlossgarten 5, 91054 Erlangen, Germany
* Corresponding author.
E-mail address: [email protected] (C. Joachim).
(This manuscript has been submitted to Marine Micropaleontology)
Abstract
Calcareous nannofossils of the Paleocene-Eocene thermal maximum (PETM) have been investigated
from an equatorial setting (Demerara Rise; ODP Site 1258C; 196.80-191.70mbsf ). The PETM
was possibly caused by a massive carbon injection, creating environmental changes, which caused a
warming of deep ocean water currents. The carbon isotope excursion (CIE), typical for the PETM, is
preceded by an initial warming phase, while the PETM is marked by warm, oligotrophic conditions.
Calcareous nannofossil counts have been obtained in high resolution, with two cm sample intervals
throughout the major part of the event. The diversity of calcareous nannofossils in the studied
interval amounts to 85 ecophenotypes. PETM excursion floras can be divided in two groups: 1)
Small taxa – or taxa with a large central opening, like Coccolithus minimus and Coccolithus latus, are
here regarded as ecophenotypes of Coccolithus pelagicus. Small ecophenotypes of C. pelagicus occur
in high total abundances during the peak phase of the event and are interpreted as an adaptation
to higher nutrient demand caused by higher metabolic rates due to higher temperatures and
oligotrophic conditions during the PETM at this site. 2) Abnormal developed discoasters are not
restricted to the PETM, but occur frequently during the event, contemporaneous to an elevated
diversity of Discoaster.
Key words: PETM, ocean acidification, global warming, abnormal developed discoasters, calcareous
nannofossil evolution.
2.1. Introduction
The late Paleocene- early Eocene climatic evolution is characterised by at least three hyperthermal
events (e.g. Thomas et al., 2000; Zachos et al., 2001),of which the Paleocene-Eocene thermal
maximum (PETM; ~55Ma) is the most prominent (e.g. Kennett & Stott, 1991; Sloan, 1998;
Röhl et al., 2000). Sluijs et al. (2007) showed that the onset of environmental changes, recorded
by the acme of the thermophilic dinoflagellate cyst Apectodinium and of surface-ocean warming,
preceded the negative carbon isotope excursion (CIE) marking the PETM by several thousand
years. The gradual ocean warming possibly led to a sudden release of ~1500-2000 *109 tons of
14
INTRODUCTION
methane from decomposing gas hydrate reservoirs to the ocean-atmosphere system (Dickens et al.,
1995; Dickens et al., 1997; Dickens, 2000), causing a shallowing of the Carbonate Compensation
Depth (CCD). Alternative or additional mechanisms to explain the negative δ13C excursion, are the
release of carbon from permafrost and peat in Antarctica (DeConto et al., 2012) and the ventilation
of DOC, stored under anoxic conditions in the abyssal Southern Ocean (Sexton et al., 2011).
Consequences of this release of carbon to the ocean were intensified warming of the atmosphere
and oceans, substantial changes in ocean chemistry, and the reorganization of the global carbon
cycle (Kennett & Stott, 1991; Koch et al., 1992; Thomas et al., 2002; Zachos et al., 2003, 2005;
Tripati & Elderfield, 2005; Sluijs et al., 2006; Röhl et al., 2007). Estimates of CO2 concentrations
in the atmosphere during the PETM range between 1000 and 3500ppm and are indicated by
findings from paleosols, marine boron isotopes and leaf stomal indices (Royer et al., 2004; Yapp,
2004). The estimated level of 750ppm of CO2 at the end of the 21th century (Caldeira & Wickett,
2003) predicts similar ecological conditions for the oceans of the future. Data from an Earth system
model, however, suggest a much slower peak rate of carbon addition, than the present rate (Cui et
al., 2011).
Fig. 2.1: Paleogeographic reconstruction (55.0Ma). Location of Demerara Rise and other important PETM
calcareous nannofossil sites, reconstructed from http://www.odsn.de.
Calcareous nannofossils and other microfossils of PETM age have been intensively studied from
several locations (Fig. 2.1) including Demerara Rise, ODP Site 1259, 1260 (Jiang & Wise., 2006;
Mutterlose et al., 2007), ODP Site 1209B, Shatsky Rise, Pacific Ocean (Bralower, 2002; Tremolada
et al., 2008) and Walvis Ridge, South Atlantic ODP Site 1262, 1263 (Raffi et al., 2009), high
latitudinal sites like the Weddell Sea (Bralower, 2002) and Maud Rise ODP Site 690B (Tremolada
et al., 2008). “Malformed” coccoliths, interpreted to reflect surface ocean acidification and shortliving excursion taxa have been described from different localities worldwide (Bybell & Self-Trail,
1995; Kelly et al., 1996, Jiang & Wise, 2006; Mutterlose et al., 2007; Raffi & De Bernardi, 2008;
Raffi et al., 2009). The term “malformation” in coccoliths is, however, inadequate defined, because
15
CHAPTER II
different authors use varying definitions, as well as different taxonomic concepts. Though the causes
of “malformation” are poorly understood, surface water acidification has been suggested as a possible
trigger by various authors (Jiang & Wise, 2006; Mutterlose et al., 2007; Erba et al., 2010; Self-Trail
et al., 2012).
The equator is a key region for the study of the PETM, because it provides a record of possible
changes of the wind-driven equatorial upwelling system. Furthermore, the equator experienced
the most extreme temperatures during the PETM, ~31°C surface water temperatures (Thomas et
al., 2006). Equatorial upwelling systems are therefore archives for oceanographic changes, which
document the complex interplay of ocean chemistry, climate, circulation and plate tectonics (Van
Andel et al., 1977). Our study is based, in contrast to Jiang & Wise (2006) and Mutterlose et al.
(2007), on a more differentiated taxonomy, following Bown (2005), a by a factor three higher
sample resolution and total abundance data, based on the settling slide technique, following Geisen
et al. (1999).
The objective of this high-resolution study of the PETM from an equatorial site is to analyse
a sequence of nannofossil patterns throughout the PETM and answer the question if “malformed”
calcareous nannofossils are restricted to the PETM and if they reflect surface water acidification. We
hypothesize that temperature and productivity have been underestimated as a driving force, causing
this phenomenon.
2.2. Section and material
This high-resolution study of calcareous nannofossils (167 samples) supported by isotope
geochemistry (Fig. 2.2) has been performed on a 5.10m thick section of ODP core 1258C (196.80191.70mbsf ) from Leg 207 Demerara Rise. Core 1258C has been taken ~380km off the coast of
Suriname, South America (9°25’N, 54°45’W) and reflects an equatorial setting of the Western
Atlantic. The investigated site had a paleolatitude of 4°N, a paleo-water-depth of lower-bathyal to
upper-abyssal, and an average sedimentation rate of 1.5cm/ka (Erbacher et al., 2004). Therefore,
the investigated 5.10m thick Paleocene-Eocene interval covers approximately 340ka. The 5.10m
thick interval is composed of a 1.03m thick pre-PETM interval (196.80-195.77mbsf ), the 2.17
m thick PETM interval (195.77-193.60mbsf ) and the 1.85m thick post-PETM interval (193.60191.70mbsf ). The PETM interval itself can be subdivided into the body (195.77-195.22mbsf ),
and the recovery interval (195.22-193.60mbsf ). The body includes the peak phase (195.77195.55mbsf ).
A 55cm thick clay layer (195.77-195.22 mbsf ), attributed here to the body of the PETM,
was deposited during a period of 70-80ka (Röhl et al., 2000; Farley & Eltgroth, 2003). The total
duration of the PETM is 120-220ka (Farley & Eltgroth, 2003; Murphy et al., 2010).
16
METHODS
2.3. Methods
2.3.1. Geochemistry
The calcium carbonate content (Fig. 2.3) was measured by using a “Carbonate-bomb” (Müller &
Gastner, 1971). Each sample was analysed at least twice with a sediment volume of 0.5g for each
measurement with an accuracy of 3wt%. The δ13Cbulk values of all samples with a carbonate content
of <20% were analysed by Dr. Nils Andersen, Leibnitz Laboratory for Radiometric Dating and Stable
Isotope Research CAU Kiel, using a Finnigan MAT 251 mass spectrometer in combination with
a Kiel I prototype. The investigated material is housed at the Department of Geology, Mineralogy
and Geophysics, Ruhr-University Bochum.
2.3.2. Calcareous nannofossils
The calcareous nannofossil intervals have been studied in a two cm resolution for the interval
from 195.95-194.05mbsf. The outer intervals (196.80-195.95mbsf and 194.05-191.70mbsf ) were
sampled in five cm intervals. Smear and settling slides were used to gain data of total abundances
and diversity. The taxonomic status of some calcareous nannofossils occurring in this interval is still
under discussion. Bown (2005) described several new species in the genus Coccolithus (Coccolithus
minimus, Coccolithus latus, Coccolithus foraminis and Coccolithus bownii), mainly on the base of
different sizes of coccolith length and width as well as length and width of the central opening. In this
paper we refer to this species as ecophenotypes, because we are not convinced of their independent
taxonomic status. We rather see an advantage to distinguish between them, as the occurrence of
different ecophenotypes is possibly related to ecological changes during the PETM. The random
settling technique (Geisen et al., 1999) was applied for a set of 167 slides. The abundances were
determined by counting 300-400 specimens/slide and once obtained, corrected to the total water
column within the settling boxes (Geisen et al., 1999). Rare coccolith species were counted by the
acquisition of two additional random traverses of each individual slide, and counted “1”. All counts
were performed by the use of an Olympus BH-2 light microscope with cross-polarized light at a
magnification of x1500. Pictures were taken with an Olympus UC30 Digital colour camera.
Preservation of calcareous nannofossils was checked, following the criteria of Roth &
Thierstein (1972) and Roth (1973). Therefore, it has been distinguished here between etching (E)
and overgrowth (O). Category E1/O1 shows slight etching or overgrowth, E1-E2/O1-O2 little
etching or overgrowth, E2/O2 moderate etching or overgrowth, E2-E3/O2-O3 increased etching
or overgrowth and E3/O3 severe etching (all smaller calcareous nannofossils are dissolved). Strong
overgrowth results in problems identifying specimens.
The diversity of calcareous nannofossils was here quantified as species richness (S), which is
also referred to as simple diversity. Evenness (E) and the Shannon Diversity Index (HS) (Shannon,
1948) have been calculated with a MultiVariate Statistical Package (MVSP) (Fig. 2.2). The Evenness
(E) characterizes the homogeneity of the assemblage, whereby “0” is 1 single species preferred
and “1” is all species are equal in abundance. The Shannon Index expresses heterogeneity of an
17
CHAPTER II
assemblage, where high values express a high heterogeneity. The programme STATISTICA was
used to analyse the data. The Kolmogorov-Smirnov test with Lilliefors correction was used to check
for normal distribution; non-parametric tests were applied for non-normal distributed data. A
Spearman-type correlation matrix (Fig. 2.4) was calculated for 14 parameters (CaCO3, δ13Cbulk,
δ18Obulk, Campylosphaera spp., Chiasmolithus spp., C. minimus, C. latus + C. foraminis, C. bownii,
Sphenolithus spp., Discoaster araneus, teratoid discoasters, Rhomboaster cuspis, Toweius spp. and
Fasciculithus spp. by the use of STATISTICA. Samples from the barren or almost barren samples
(195.77-195.32mbsf ) are excluded from the matrix.
Productivity and temperature were plotted with the paleoenvironmental index (PI) of Gibbs
et al. (2010), based on the equation: PI= Toweius spp.% / Discoaster spp.% + Sphenolithus spp.%
+ Toweius spp.%. Toweius is interpreted to indicate mesotrophic and cool conditions, whereas
Discoaster and Sphenolithus represent oligotrophic, warmer conditions (Bralower, 2002; Gibbs et al.
2006 a & b).
2.4. Results
2.4.1. Geochemistry
The δ13Cbulk record (Fig. 2.2) of the pre-PETM interval indicates values of ~0.89‰ (196.80195.79mbsf ). Following this interval the δ13Cbulk curve shows three negative peaks of up to -11‰
within the negative anomaly (peak phase). In the following course of the event, the carbon isotope
values become more positive (-1.25‰, 195.40mbsf ) and recover to pre-PETM values. The CIE
ends in 193.69mbsf.
The calcium carbonate content of the pre-PETM interval (196.80-195.77mbsf ) ranges from
33.3% to 61.4%, in the PETM it declines to 13.6% (195.77mbsf ) and 0 (195.75-195.36mbsf ).
Following this the carbonate values increase steadily to 50.3% (194.80mbsf ) (Fig. 2.3).
The PETM is subdivided into three different phases: 1) the body (195.77-195.22mbsf ) is interpreted
as a semistable state, following the initial forcing, lasting approximately 60,000 years (Bowen et
al., 2004). 2) The peak phase (195.77-195.55mbsf ), which is the part of the CIE with the most
negative results (included in the body). 3) The recovery (195.22-193.60mbsf ) is the recovery of the
Earth’s systems, to a state in the earliest Eocene, similar to that of the late Paleocene (Bowen et al.,
2004).
The preservation of calcareous nannofossils in the pre-PETM interval (196.80-195.77mbsf )
varies from E1, to E2-E3 in the PETM (195.77-194.31mbsf ). In the subsequent part of the core
preservations of E1-E2 characterize the recovery phase and the post-PETM interval (Fig. 2.2).
Absolute abundances show values with a maximum of 1.97x109 specimens/g sediment in the
pre-PETM interval (196.80-195.79mbsf ) (Fig. 2). The average value in this interval is 9.84x108
18
Fig. 2.2: Stratigraphic framework, sample density, core photo, calcium carbonate content (CaCO3), δ13Cbulk, species richness (S), absolute abundances, evenness,
Shannon index (HS), preservation index, paleoenvironmental index of Gibbs et al. (2010), abundance of the genera Coccolithus and Toweius as well as PETM intervals
and interpretation.
RESULTS
19
CHAPTER II
specimens/g sediment. During the peak phase (195.77-195.55mbsf ) abundances drop to 0
(195.77mbsf, 195.75mbsf ) and stay below 3x106 specimens/g sediment for the remainder of this
interval. In the interval (195.55-195.38mbsf ) abundances increase gradually to a value of 2x108.
2.4.2.1. Diversity patterns
A total of 85 calcareous nannofossil taxa have been identified throughout the investigated interval.
The most frequent species are Coccolithus pelagicus (40.5%) and Toweius pertusus (27%), which
account for more than 2/3rd of the assemblages. C. bownii (4.2%), Sphenolithus moriformis (3.5%),
and C. eodela (2.7%) are next common.
Discoaster is the most diverse group during the investigated interval. Twenty six different
ecophenotypes were distinguished. Discoasters, which show an aberrant calcification, were counted
as teratoid discoasters (Fig. 2.5).
In the pre-PETM interval (196.80-195.77mbsf ) species richness (S) ranges between 20
and 32. In the peak phase (195.77-195.55mbsf ) S declines to a maximum of 5 and increases
subsequently to 5-16 (sample 195.55mbsf, 195.53mbsf ). Values for the evenness (E) rise from
~0.5 in the pre-PETM interval (196.80-195.77mbsf ) to 0.8-1 during the peak phase (195.77195.55mbsf ). During the recovery phase (195.22-193.60mbsf ) values drop slowly to the prePETM values of 0.5. The Shannon Index (HS) has a value of ~2 in the pre-PETM interval (196.80195.77mbsf ), drops in the peak phase (195.77-195.55mbsf ) to ~0.5 -1 and shows highest values of
> 2 in the upper part of the body (195.55-195.22mbsf ). During the recovery (195.22-193.60mbsf )
values slowly decline to those typical of pre-PETM conditions ~2.
2.4.2.2. Nannofossil intervals
Within the final stage of the pre-PETM interval (196.80-195.77mbsf ) total abundances, as well as
abundances of C. pelagicus, Campylosphaera spp. and Fasciculithus spp. show a drastic increase. This
phase is here called “initial warming phase” (196-195.77mbsf ). During this initial warming phase
Toweius spp., however, shows a marked decline in abundance and a shift from smaller to bigger
specimens takes place within Campylosphaera spp..
The peak phase (195.77-195.55mbsf ) is characterised by a decline of abundance of most
nannofossil taxa to 0. Nannofossils occurring in the body with extraordinary high abundances are C.
minimus (195.47-195.22mbsf ), R. cuspis, and C. bramlettei (maximum abundance in 195.38mbsf ).
R. cuspis first occurrence datum (FOD) is 195.51mbsf. These three taxa are rare in the post-PETM
interval (last common occurrence (LCO) in 194.50mbsf ).
C. bownii has its first common occurrence (FCO) at 195.43mbsf, within the body; its
LCO is in the recovery phase (194.23mbsf ). The FOD of D. araneus is in 195.51mbsf. Teratoid
discoasters and excursion nannofloras are typical for the recovery phase (195.22-193.60 mbsf ). The
top of the recovery interval is defined by an increase of the carbon isotope values at 193.60 mbsf.
20
Fig. 2.3: Abundance of several nannofossil taxa, correlated to δ13Cbulk, (Toweius pertusus, Toweius occultatus, Toweius eminens, Toweius serotinus, Coccolithus pelagicus.
Coccolithus latus + Coccolithus foraminis, Coccolithus minimus, Coccolithus bownii, Campylosphaera dela, Campylosphaera eodela, Chiasmolithus spp., Coronocyclus
bramlettei, Neochiastozygus spp., Discoaster spp., Fasciculithus spp. and Rhomboaster cuspis) during the PETM intervals.
RESULTS
21
CHAPTER II
PETM specific excursion taxa (R. cuspis, C. bownii, D. araneus and teratoid discoasters) have their
LCO at 194.23mbsf. In the upper part of the recovery phase (194.31-193.60mbsf ) abundances of
Toweius decline and those of Coccolithus increase (194.21-193.75mbsf ). Following that, Toweius
shows increasing and Coccolithus decreasing abundances (193.55-192.80mbsf ). The post-PETM
(193.55-191.70mbsf ) is the interval following the PETM and its excursion taxa.
The uppermost centimetre of the studied interval, shows an assemblage shift with increasing
abundances of teratoid discoasters and decreased values of the PI index. This interval (192.05191.75mbsf ) is also marked by an increase of C. latus and C. foraminis, as well as a higher Shannon
diversity.
2.4.2.3. Statistics
he correlation matrix (Fig. 2.4) shows strong positive correlations between CaCO3, δ13Cbulk, δ18Obulk
and Toweius spp. (p<0.001), as well as highly significant negative correlation of CaCO3, δ13Cbulk
and δ18Obulk to Campylosphaera and the excursion taxa C. bownii and D. araneus (p<0.001).
In contrast the δ18Obulk record shows significant negative correlations to the various Coccolithus
ecophenotypes with a large central opening (C. latus + C. foraminis) (r=-0.32). Campylosphaera
spp. strongly correlates positively with C. latus and C. foraminis (r=0.45) and the known PETM
excursion taxa C. bownii (r=0.62), D. araneus (r=0.59) and teratoid discoasters (r=0.35) (Bybell &
Self-Trail, 1995; Jiang & Wise, 2006; Mutterlose et al., 2007; Raffi & De Bernardi, 2008; Raffi et
al., 2009). C. minimus indicates only correlations of minor significance. C. latus + C. foraminis show
significant correlations with C. bownii (r=0.49), D. araneus (r=0.41) and less significant with the
teratoid discoasters (r=0.27). C. bownii significantly correlates with D. araneus (0.73) and teratoid
discoasters (0.36), as well as strong anticorrelations with Toweius spp.. D. araneus suggests significant
correlations with the teratoid discoasters and R. cuspis as well as strong anticorrelations with Toweius
spp. and Fasciculithus spp.
2.5. Discussion
2.5.1. Excursion floras and PETM conditions
Traditionally, the term “transient excursion taxa” has been applied to R. cuspis and R. bramlettei as
well as to the teratoid discoasters, D. araneus and Discoaster anartios, which are restricted to the CIE
(e.g. Bybell & Self-Trail, 1995; Bralower, 2002; Kahn & Aubry, 2004; Agnini et al., 2007a, 2007b;
Aubry et al., 2007; Mutterlose et al., 2007; Raffi & De Bernardi, 2008; Raffi et al., 2009). In this
study C. latus, C. foraminis, C. minimus, C. bownii, C. bramlettei, D. araneus, D. anartios, teratoid
discoasters, Fasciculithus thomasii, R. cuspis Rhomboaster spineus and R. bramlettei are considered
excursion taxa, because of their PETM specific high abundance. Due to their morphology these taxa
can be divided into two groups (Fig. 2.6): 1. Small coccoliths like C. minimus and ecophenotypes
of Coccolithus sp. with a large central opening (C. latus and C. foraminis); 2. Discoasters, with a
higher variability of shape or structural loss (D. araneus, D. anartios and teratoid discoasters with a
concrete parent taxon).
22
CaCO3
18
-0.66
0.04
0.15
-0.32
-0.47
-0.10
-0.67
-0.34
-0.17
0.39
0.23
1.00
δ O
Campylosphaera spp.
1.00
-0.01
-0.15
0.45
0.62
0.11
0.59
0.35
0.21
-0.38
-0.25
Chiasmolithus spp.
p<0.05
1.00
-0.06
-0.11
-0.30
-0.19
-0.21
-0.13
-0.15
0.14
0.03
Coccolithus minimus
1.00
0.12
0.10
-0.19
-0.14
-0.21
0.04
0.21
0.25
p<0.001
1.00
0.49
0.23
0.41
0.27
0.21
-0.22
-0.09
C. latus + foraminis
Fig. 2.4: Correlation matrix of CaCO3, δ13C, δ18O and selected calcareous nannofossil taxa.
195.75-155.32 mbsf excluded
0.69
-0.54
0.24
0.25
-0.23
-0.81
-0.28
-0.71
-0.45
-0.42
0.46
0.44
0.67
δ O
Campylosphaera spp.
Chiasmolithus spp.
Coccolithus minimus
C. latus + C. foraminis
Coccolithus bownii
Sphenolithus spp.
Discoaster araneus
teratoid discoasters
Rhomboaster cuspis
Toweius spp.
Fasciculithus spp.
-0.51
-0.02
0.18
-0.30
-0.46
-0.12
-0.50
-0.19
0.09
0.30
0.22
1.00
0.51
13
18
1.00
δ C
δ C
13
CaCO3
Coccolithus bownii
1.00
0.29
0.71
0.41
0.22
-0.45
-0.07
Sphenolithus spp.
1.00
0.31
0.25
0.07
-0.11
-0.12
Discoaster araneus
1.00
0.41
0.25
-0.46
-0.39
teratoid discoasters
1.00
0.29
-0.20
-0.32
Rhomboaster cuspis
1.00
-0.11
-0.21
Toweius spp.
1.00
0.18
Fasciculithus spp
1.00
DISCUSSION
23
CHAPTER II
Within the peak phase group 1, shows high relative abundances, while results are masked by the
shallowing of the CCD during this interval (195.77-195.60mbsf ). Therefore total nannofossil
abundances are very low (<10). Due to their high relative abundance and their delicate structure,
we assume that the total abundances of these taxa during this interval were significantly higher
compared to more robust and dissolution-resistent taxa like C. pelagicus s.str..
It is likely that C. latus, C. foraminis and C. minimus are ecophenotypes of C. pelagicus,
caused by environmental factors like changes in surface water temperature and trophic levels. C.
latus, C. foraminis, and C. minimus are species described by Bown (2005) from the Tanzania section
and have hardly been observed, respectively distinguished from C. pelagicus in previous publications.
Results from the correlation matrix do not indicate clear preferences of the small Coccolithus
ecophenotype. C. minimus shows positive correlation with Fasciculithus (0.21), which is interpreted
to indicate warm oligotrophic conditions (e.g. Haq & Lohmann, 1976) and Toweius (0.25), seen
as a cosmopolitan generalist without any preference (Mutterlose et al., 2007). Furthermore there
are negative correlations of C. minimus with teratoid discoasters and Sphenolithus, which are both
interpreted to reflect warm oligotrophic (Bralower, 2002) conditions (-0.19). The correlation of C.
minimus with δ13Cbulk shows positive values (0.25) in contrast to D. araneus (-0.71), which has been
interpreted as an effect of lower pH values (e.g. Bybell & Self-Trail, 1995; Jiang & Wise, 2006;
Mutterlose et al., 2007; Raffi & De Bernardi, 2008; Raffi et al., 2009; Self-Trail et al., 2012), and
C. bownii, which shows strong significant negative correlation with δ13Cbulk (-0.81). C. latus, with
its strong correlation to C. bownii, and D. araneus shows clearly a status of an excursion taxon with
affinities to PETM specific conditions.
2.5.2. Ocean acidification
The occurrence of small coccoliths, teratoid discoasters and the extinction of Fasiciculithus spp. are
interpreted by several authors as a result of surface water pH changes, affecting the calcification
process of the haptophyte cells at the onset of the PETM (e.g. Bybell & Self-Trail, 1995; Jiang &
Wise, 2006; Mutterlose et al., 2007; Raffi & De Bernardi, 2008; Raffi et al., 2009; Self-Trail et
al., 2012). The interpretations are based on observations by Riebesell et al. (2000). Riebesell et al.
(2000) reported reduced calcite production and malformation with increased CO2 concentrations
(280p.p.m.v. to 750p.p.m.v.) in culturing experiments with Emiliania huxleyi and Gephyrocapsa
oceanica. Increasing pCO2 causes a decrease in cell growth rate of 9% and 29% in E. huxleyi and C.
braarudii (Müller et al., 2010). Calcification in marine organisms is not only controlled by pH but
also by the calcite saturation state (Ω-cal) (Langer et al., 2006; Trimborn et al., 2007), which in turn
is influenced by dissolved inorganic carbon (DIC) and pH. While a 0.25 to 0.45 unit decline in
surface water pH is possible for the PETM (Ridgwell & Schmidt, 2010), reconstructed nannofossil
production, based on methods independent from dissolution of the risen CCD (for example Sr/
Ca) show that there is no evidence in the PETM for interruption of phytoplankton carbonate
production (e.g. Stoll et al., 2007; Gibbs et al., 2010). Direct effects of ocean acidification on
surface calcifiers during the PETM may have been limited because of a relatively slow rate of
24
Fig. 2.5: Abundance of nannofossil taxa with focus on the genus Discoaster (Sphenolithus spp., Cruciplacolithus spp., Discoaster araneus 9 rays, Discoaster araneus 8 rays,
Discoaster araneus 7 rays, Discoaster araneus 6 rays, Discoaster araneus 5 rays, Discoaster diastypus, Discoaster lenticularis, Discoaster cf. D. mohleri, Discoaster barbadiensis,
Discoaster multiradiatus, Discoaster delicatus, Discoaster cf. D. nobilis, Discoaster salisburgensis, teratoid discoasters (teratoid Discoaster spp., teratoid Discoaster cf. D. mohleri
and teratoid Discoaster cf. D. nobilis)) during the investigated interval.
DISCUSSION
25
CHAPTER II
carbon input (Zeebe, 2012). Furthermore, latest acidification experiments suggest a rapid (within
~500 asexual generations = 320 days) adaptive evolution in E. huxleyi to higher CO2 concentrations
(Lohbeck et al., 2012) and the discovery of a heavily calcified E. huxleyi morphotype in modern
waters with low pH (Beaufort et al., 2011; Smith et al., 2012) raises doubts on the interpretation
of calcareous nannofossils and ocean acidification during the PETM. Coccolith size, however, is
indeed strongly linearly correlated to both coccosphere- and cell diameter (Henderiks, 2008). For
the peak phase of the PETM this would suggest, taking the elevated total abundances of C. minimus
into account, that a shift to highly abundant smaller ecophenotypes takes place.
2.5.3. Temperature
The total abundances of C. pelagicus, a warm water taxon in the Paleocene (Haq & Lohmann, 1976)
and concomitant decrease of Toweius spp., interpreted as a mesotrophic cool water taxon (Bralower,
2002; Tremolada & Bralower, 2004; Gibbs et al., 2006a), possibly indicate rising temperatures
during the initial warming phase, compared to the earlier stages of the pre-PETM interval. The
same prominent decrease in abundance of Toweius spp. is recognized in the Alamedilla section
(Spain) of Monechi et al. (2000), while the decrease is concomitant to the CIE. Changes in the
assemblage composition, like the decline of the genus Toweius spp., precede the CIE onset, similar
to some progressive changes in the assemblage composition of foraminifera reported from Shatsky
Rise (Petrizzo, 2007). The same temperature increase is reflected in the samples preceding the CIE,
even if the signal of the PI index is not very strong. The high total abundance of C. bownii, in the
body, compared to the (PI) index, suggests a relation to the elevated temperatures. During the
PETM the global temperature increased by more than 5°C in less than 10,000 years (Zachos et al.,
2008). Sea surface temperatures near the North Pole increased from ~18°C to over 23°C during
the event (Sluijs et al., 2006). In the equatorial Pacific seas surface temperatures rose by 4° to 5°
C (Zachos et al., 2003), thermocline temperatures warmed by 3°C (Tripati & Elderfield, 2004).
Bottom waters in the equatorial Pacific warmed by 4 to 5°C, intermediate waters warmed before the
CIE (Tripati & Elderfield, 2005). Half the recovery phase of our site is characterised by decreasing,
but still elevated temperatures, compared to the pre-PETM interval. Jiang & Wise (2006) and
Mutterlose et al. (2007) report the same acme (~25%) of C. bownii in the PETM at Site 1259B and
1260. In southern Tanzania (TDP Site 14, Indian Ocean) C. bownii appears in high values (~25%)
in three distinctive peaks within the peak phase (Bown & Pearson, 2009). The pattern of the PI
index of Demerara Rise, compared to the PI index patterns of the sites of Gibbs et al. (2010), ODP
Site 690 (Southern Ocean) shows similar results, in contrast to ODP Site 1209 (Pacific Ocean) and
Bass River (New Jersey).
“Malformation” in calcareous nannofossils is defined as an exceptional variability of shape
or structural loss and is observed in some species of Discoaster (group 2). Discoasters are, however,
nannoliths and their relationship with coccolithophores is uncertain (Bown, 1997). Nannoliths are
thought to be formed by haptophytes, but are probably mineralized by a different process to either
heterococcoliths or holococcoliths (Young et al., 1999). Therefore, the comparison
26
Fig. 2.6: Abundance of calcareous nannofossil groups 1 (Coccolithus latus, Coccolithus foraminis, Coccolithus minimus), Coccolithus bownii (the typical PETM
excursion taxon) and group 2 (Discoaster araneus, Discoaster anartios and teratoid discoasters).
DISCUSSION
27
CHAPTER II
between teratoid discoasters (e.g. Bybell & Self-Trail, 1995; Jiang & Wise, 2006; Mutterlose et
al., 2007; Raffi & De Bernardi, 2008; Raffi et al., 2009) in the PETM and malformed E. huxleyi
in acidification experiments of Riebesell et al. (2000) has to be seen very critical when it comes to
the interpretation of the factor causing the phenomenon. D. araneus shows a range of five to nine
rays during the body of the PETM, and five to seven rays during the recovery interval. Discoaster
shows a short-term diversification during the PETM-interval (Fig. 2.6). The appearance of D.
araneus has been reported from several PETM sites within the peak phase (Jiang & Wise, 2006;
Mutterlose et al., 2007); it is, however, absent in Tanzania (Bown & Pearson, 2009). The preference
of D. araneus for warm surface waters is based on its relative abundance in the early PETM of
equatorial sites (Mutterlose et al., 2007). D. araneus is an excursion taxon but not a teratoid form,
because it is lacking a concrete ancestral parent taxon (Bown & Pearson, 2009), and due to its
longevity, abundance and distribution (Kahn & Aubry, 2004; Raffi et al., 2005; Bown & Pearson,
2009). Discoaster seems to gain by the specific PETM conditions, since a radiation of the genus
with six new species (D. araneus, D. diastypus, D. lenticularis, D. barbadiensis, D. anartios and D.
salisburgensis) and a maximum diversity of 14 ecophenotypes has been observed. The environmental
conditions may thus be seen as a) a stress period causing new taxa to originate, or b) very favourable
for discoasters.
Teratoid discoasters (Fig. 2.8, 35) do not appear in the pre-PETM, they are common,
however, in the body and recovery interval (~2%), but are not restricted to the PETM. The
occurrence of teratoid discoasters is contemporaneous to a high Discoaster diversity and the
excursion taxa C. bownii (r2=0.41) and D. araneus (r2=0.41). Raffi et al. (2008) showed normal
and malformed excursion ecophenotypes of D. nobilis, D. salisburgensis, and D. multiradiatus.
These malformed taxa neither show excessive growth nor a tendency to build extraordinary small
nannoliths. Malformation of these excursion taxa is given by a structural loss and incompleteness of
the plates. Due to the high abundance of malformed discoasters during the PETM, several PETM
specific ecological factors may support this phenomenon (e.g. higher temperature, productivity
changes, surface water acidification).
Malformation is, however, not restricted to the discoasters, but occurs also in Fasciculithus
spp. The structure of Fasciculithus thomasii, interpreted by Raffi & De Bernardi (2008) as a weakly
calcified F. tympaniformis suggested surface water acidification disrupting the calcite production.
However, calcifying patterns in F. thomasii compared in several PETM sites are constant and
therefore it seems unlikely to be teratoid forms. F. thomasii is also seen as an excursion restricted
species by Bown & Pearson (2009). Based on its close association with non-excursion discoasters,
Fasciculithus has been interpreted as an oligotrophic warm water taxon (Haq & Lohmann, 1976;
Mutterlose et al., 2007). At equatorial sites Fasciculithus declines significantly, but is present in the
fossil record until NP10b at Demerara Rise (Jiang & Wise, 2006). In mid and high latitudes the
abundance of Fasciculithus increases in the PETM (Bralower, 2002; Tremolada & Bralower, 2004).
The extinction of Fasciculithus in the PETM, however, might be triggered by higher temperatures.
The increase in high and mid latitudes during the PETM (Bralower, 2002; Tremolada & Bralower,
28
DISCUSSION
2004) might suggest a temperature threshold, causing the extinction of Fasciculithus spp.
2.5.4. Productivity
The PI index indicates a certain shift to higher temperature and lower productivity in the initial
warming phase. Productivity in the subsequent peak phase is high, but results of the PI index are
influenced by carbonate dissolution, caused by the CCD, before it decreases to a level lower than
during the pre-PETM, indicating more oligotrophic conditions during the body and early recovery.
The low productivity at open-ocean sites demonstrates a global but transient increase in oligotrophy
during the onset and peak, which may have resulted from a widespread increase in stratification
and less efficient biological pumping (Gibbs et al., 2006a). Enhanced biological productivity and
upwelling during the PETM are indicated by micropaleontological and geochemical proxies for the
Tethyan Realm (Schmitz et al., 1996, 1997; Speijer et al., 1996, 1997; Charisi & Schmitz, 1998;
Speijer & Schmitz, 1998; Speijer & Wagner, 2002). A re-evaluation of the “productivity feedback
hypothesis” (Bains et al., 2000) showed, however, that export production did not rapidly remove
excess carbon from the atmosphere (Torfstein et al., 2010). An acme of the tropical dinoflagellate
Apectodinium and its migration towards the poles is associated with higher temperatures and
enhanced continental runoff, as well as stratification and eutrophic conditions in coastal waters
(Bujak & Brinkhuis, 1998; Crouch et al., 2003; Egger et al., 2003; Zachos et al., 2006). The results
from the PI-index of Gibbs et al. (2010) suggest low productivity throughout the body and the
early recovery of the PETM for our equatorial Atlantic site, and therefore an affected / sluggish
equatorial upwelling during this interval. Evidence from eolian grain size shows a rapid decrease in
the intensity of atmospheric circulation at the Paleocene–Eocene boundary (Janecek & Rea, 1983).
Newest models suggest a change of ocean circulation patterns for the PETM (Lunt et al., 2011) in
particular a decrease of the equatorial upwelling for the early stage of the PETM (Winguth et al.,
2012).
The occurrence of C. minimus during the PETM might represent an adaptation to the
trophic changes during the event. Asides the small size, no malformation is observed on the
coccoliths. While increased temperatures lead to accelerated metabolic activity and the growth rate
of phytoplankton is generally positively correlated with temperature (Lund, 1949; Talling, 1955;
Eppley, 1979), smaller phytoplankton cells have a greater potential for nutrient acquisition from
low-nutrient environments (Raven, 1998).
2.6. Conclusion
The biological perturbations of the PETM are concerted by temperature and productivity. The
paleoenvironmental index of Gibbs et al. (2010) was used to assess perturbations of temperature
and nutrients, indicating high temperatures and oligotrophic conditions for the PETM at
Demerara Rise. Temperatures start to rise in the interval preceding the CIE and are accompanied
by a major shift in the calcareous nannofossil assemblage. The total nannofossil diversity exceeds
85 ecophenotypes. The excursion flora of the PETM interval was divided into two morphology29
CHAPTER II
based groups. 1) Small ecophenotypes of C. pelagicus, like C. latus, C. foraminis and C. minimus,
which are thought to be stress forms, possibly caused by elevated temperatures and oligotrophy
during the PETM. Concerning the low total abundance, we suggest to study the biometry of C.
pelagicus in an interval covering the PETM and other hyperthermal events to confirm the idea of an
intraspecific response. 2) Teratoid discoasters are not restricted to the PETM. The genus Discoaster
spp. is favoured by the post-PETM conditions, showing immense adaptive radiation. The genus
Fasciculithus, becoming extinct in the early Eocene shows teratoid specimens as well. The extinction
of Fasciculithus might also be more related to elevated temperatures.
2.7. Acknowledgements
We would like to thank Dr. Nils Andersen (Kiel) for his critical comments and the German program
of “Biological Impacts of Ocean Acidification (BIOACID)” for the financial support, as well as the
two anonymous reviewers for their comments, improving the manuscript.
Fig. 2.7: All scale bars = 5µm 1) Toweius callosus; crossed nicols (XN); sample 1258C 8R 5w 91-92; 194.11mbsf.
2) Toweius eminens; XN; sample 1258C 8R 7w 60-61; 196.80mbsf. 3) Toweius eminens; XN; sample 1258C
8R 6w 66-67; 195.36mbsf. 4) Toweius eminens; XN; sample 1258C 8R 6w 62-63; 195.32mbsf. 5) Toweius
occultatus; XN; sample 1258C 8R 6w 119-120; 195.89mbsf. 6) Toweius pertusus; XN; sample 1258C 8R
5w, 40-41; 193.60mbsf. 7) Toweius pertusus (sphere); XN; sample 1258C 8R 5w 99-100; 194.19mbsf.
8) Toweius serotinus; XN; sample 1258C 8R 6w 145-146; 194.65mbsf. 9) Toweius serotinus; XN; sample
1258C 8R 6w 55-56; 195.25mbsf. 10) Toweius sp. 2 (Bown, 2005); XN; sample 1258C 8R 4W 45-46;
192.15mbsf. 11) Cyclicargolithus luminis; XN; sample 1258C 8R 4w 20-21; 191,90mbsf. 12) Coccolithus
pelagicus; XN; sample 1258C 4w 100-101; 192.70mbsf. 13) Coccolithus pelagicus; XN; sample 1258C 4w
15-16; 191.85mbsf. 14) Coccolithus crucis; XN; sample 1258C 8R 4w 75-76; 192.45mbsf. 15) Coccolithus
latus; XN; sample 1258C 8R 5w 105-106; 194.25mbsf. 16) Coccolithus minimus; XN; sample 1258C 8R 6w
14-15; 194.84mbsf. 17) Coccolithus foraminis; XN; sample 1258C 8R 4w 45-46; 192.15mbsf. 18) Coccolithus
bownii; XN; sample 1258C 8R 6w 60-61; 195.30mbsf. 19) Ericsonia subpertusa; XN; sample 1258C 8R
5w 99-100; 194.19mbsf. 20) Ericsonia staerkeri; XN; sample 1258C 8R 6w 135-136; 196.05mbsf. 21)
Campylosphaera dela; XN; sample 1258C 8R 7w 31-32; 196.51mbsf. 22) Campylosphaera eodela; XN; sample
1258C 8R 6w 38 - 39; 195.08mbsf. 23) Cruciplacolithus latipons; XN; sample 4w 95-96; 192.65mbsf. 24)
Cruciplacolithus edwardsii; XN; sample 1258C 8R 7w 60-61; 196.80mbsf. 25) Cruciplacolithus asymmetricus;
XN; sample 1258C 8R 5w 93-94; 194.13mbsf. 26) Cruciplacolithus cassus; XN; sample 1258C 8R 5w
55-56; 193.75mbsf. 27) Cruciplacolithus cruciformis; XN; sample 1258C 8R 7w 60-61; 196.80mbsf. 28)
Chiasmolithus bidens; XN; sample 1258C 8R 6w 140-141; 196.10mbsf. 29) Chiasmolithus consuetus; XN;
sample 1258C 8R 6w 83-84; 195.53mbsf. 30) Chiasmolithus nitidus; XN; sample 1258C 8R 6w 145-146;
196.15mbsf. 31) Chiasmolithus solitus; XN; sample 1258C 8R 4w 100-101; 192.70mbsf. 32) Coronocyclus
bramlettei; XN; sample 1258C 5w 111-112; 194.31mbsf. 33) Umbilicosphaera ? jordanii; XN; sample 1258C
5w 10-11; 193.30mbsf. 34) Ellipsolithus sp.1; XN; sample 1258C 7w 60-61; 196.80mbsf. 35) Ellipsolithus
distichus; XN; sample 1258C 5w 100-101; 194.30mbsf. 36) Ellipsolithus bollii; XN; sample 1258C 6w 3435; 195.04mbsf. 37) Ellipsolithus macellus; XN; sample 1258C 4w 87-88; 194.07mbsf. 38) Helicosphaera
sp.1; XN; sample 1258C 6w 140-141; 196.10mbsf. 39) Helicosphaera bramlettei; XN; sample 1258C 4w
70-71; 192.40mbsf. 40) Pontosphaera formosa; XN; sample 1258C 8R 4w 40-41; 192.10mbsf.
30
APPENDIX
Fig.2.7
31
CHAPTER II
Fig. 2.8: All scale bars = 5µm 1) Lophodolithus nascens; XN; sample 1258C 8R 4w 120-121; 192.90mbsf.
2) Lophodolithus nascens; XN; sample1258C 8R 6w 15-16; 194.85mbsf. 3) Zygodiscus plectopons; XN;
sample 1258C 8R 4w 100-101; 192.70mbsf. 4) Neochiastozygus distentus; XN; sample 1258C 8R 4w 100101; 192.70mbsf. 5) Neochiastozygus rosenkrantzii; XN; sample 1258C 8R 6w 65-66; 195.35mbsf. 6)
Neochiastozygus perfectus; XN; sample 1258C 8R 6w 68-69; 195.38mbsf. 7) Neochiastozygus substrictus; XN;
sample 1258C 8R 6w 95-96; 195.65mbsf. 8) Neococcolithes protenus; XN; sample 1258C 8R 5w 107-108;
194.27mbsf. 9) Calciosolenia aperta; XN; sample 1258C 8R 6w 130-131; 196.00mbsf. 10) Syracosphaera
tanzanensis; XN; sample 1258C 8R 6w 55-56; 195.25mbsf. 11) Blackites virgatus; XN; sample 1258C 8R
6w 50-51; 195.20mbsf. 12) Holodiscolithus solidus; XN; sample 1258C 8R 4w 90-91; 192.60mbsf. 13) aff.
Laternithus spp.; XN; sample 1258C 8R 6w 109-110; 195.79mbsf. 14) Bomolithus/Discoaster megastypus;
XN; sample 1258C 8R 6w 109-110; 195.79mbsf. 15) Discoaster araneus (9 rays); XN; sample 1258C 8R 6w
66-67; 195.36mbsf. 16) Discoaster araneus (8 rays); light-field; sample 1258C 8R 6w 24-25; 194.94mbsf.
17) Discoaster araneus (7 rays); XN; sample 1258C 8R 4w 60-61; 192.30mbsf. 18) Discoaster araneus (7
rays); XN; sample 1258C 8R 6w 79-80; 195.49mbsf. 19) Discoaster araneus (6 rays); XN; sample 1258C
8R 5w 105-106; 194.25mbsf. 20) Discoaster araneus (7 rays); light-field; sample 1258C 8R 6w 22-23;
194.92mbsf. 21) Discoaster araneus (8 rays); light-field; sample 1258C 8R 6w 24-25; 194.94mbsf. 22)
Discoaster araneus (7 rays); light-field; sample 1258C 8R 6w 26-27; 194.96mbsf. 23) Discoaster sp. 1; XN;
sample 1258C 8R 4w 50-51; 192.35mbsf. 24) Discoaster sp.2; XN; 1258C 8R 6w 48-49; 195.18mbsf. 25)
Discoaster sp.3; XN; 1258C 8R 6w 34-35; 195.04mbsf. 26) Discoaster diastypus; XN; 1258C 8R 4w 65-66;
192.35mbsf. 27) Discoaster cf. diastypus; XN; 1258C 8R 6w 70-71; 195.40mbsf. 28) Discoaster sp.4; XN;
1258C 8R 4w 100-101; 192.70mbsf. 29) Discoaster sp. 4; XN; 1258C 8R 6w 109-110; 195.79mbsf. 30)
Discoaster lenticularis; XN; 1258C 8R 4w 60-61; 192.20mbsf. 31) Discoaster cf. mohleri; XN; 1258C 8R
5w 101-102; 194.21mbsf. 32) Discoaster delicatus; XN; 1258C 8R 4w 45-46; 192.15mbsf. 33) Discoaster
barbadiensis; XN; 1258C 8R 4w 25-26; 191.95mbsf. 34) Discoaster multiradiatus; XN; 1258C 8R 6w 119120; 195.89mbsf. 35) Discoaster multiradiatus (teratoid); XN; 1258C 8R 5w 101-102; 194.21mbsf. 36)
Discoaster delicatus; XN; 1258C 8R 4w 45-46; 192.15mbsf. 37) Discoaster cf. D. nobilis; XN; 1258C 8R
6w 23-24; 194.92mbsf. 38) Discoaster cf. D. nobilis; bright-field; 1258C 8R 6w 109-110; 195.79mbsf. 39)
Teratoid Discoaster nobilis; XN; 1258C 8R 4w 0-1: 191.70mbsf. 40) Discoaster falcatus; bright-field; 1258C
8R 5w 133-134; 194.53mbsf.
32
APPENDIX
Fig.2.8
33
CHAPTER II
Fig. 2.9: All scale bars = 5µm 1) Discoaster salisburgensis; XN; 1258C 8R 5w 149-150; 194.69mbsf. 2)
Discoaster anartios; light-field; 1258C 8R 6w 45-46; 195.15mbsf. 3) Teratoid Discoaster anartios morphotype;
light-field; 1258C 8R 6w 24-25; 194.94mbsf. 4) Fasciculithus sp.; XN; 1258C 8R 6w 110-111; 195.80mbsf.
5) Fasciculithus involutus; XN; 1258C 8R 4w 40-41; 192.10mbsf. 6) Fasciculithus involutus; XN; 1258C
8R 4w 30-31; 192.00mbsf. 7) Fasciculithus involutus; bright-field; 1258C 8R 4w 30-31; 192.00mbsf. 8)
Fasciculithus sp.; XN; 1258C 8R 4w 135-36; 193.05mbsf. 9) Fasciculithus sp.; XN; 1258C 8R 6w 109110; 195.79mbsf. 10) Fasciculithus sp.; XN; 1258C 8R 6w 64-65; 195.34mbsf. 11) Fasciculithus sp.; XN;
1258C 8R 5w 40-41; 193.60mbsf. 12) Fasciculithus alanii; XN; 1258C 8R 6w 110-111; 195.80mbsf. 13)
Fasciculithus thomasii; XN; 1258C 8R 6w 72-74; 195.43mbsf. 14) Fasciculithus thomasii; XN; 1258C 8R
6w 72-74; 195.43mbsf. 15) Fasciculithus thomasii; XN; 1258C 8R 6w 75-76; 195.47mbsf. 16) Fasciculithus
billii; XN; 1258C 8R 6w 75-76; 195.45mbsf. 17) Fasciculithus tympaniformis; XN; 1258C 8R 6w 111112; 195.81mbsf. 18) Fasciculithus clinatus; XN; 1258C 8R 5w 101-102; 194.21mbsf. 19) Fasciculithus
schaubii; XN; 1258C 8R 6w 110-111; 195.80mbsf. 20) Fasciculithus schaubii; XN; 1258C 8R 7w 60-61;
196.80mbsf. 21) Fasciculithus sp.; XN; 1258C 8R 6w 109-110; 195.79mbsf. 22) Bomolithus aquilus; XN;
1258C 8R 6w 5-6; 194.75mbsf. 23) Bomolithus sp.; XN; 1258C 8R 6w 0-1; 194.70mbsf. 24) Sphenolithus
moriformis; XN; 1258C 8R 6w 68-69; 195.38mbsf. 25) Sphenolithus acervus; XN; 1258C 8R 7w 11-12;
196.31mbsf. 26) Sphenolithus acervus; XN; 1258C 8R 6w 66-67; 195,36mbsf. 27) Sphenolithus anarrhopus;
XN; 1258C 8R 4w 85-86; 192.55mbsf. 28) Rhomboaster cuspis; XN; 1258C 8R 6w 81-82; 195.51mbsf.
29) Rhomboaster cuspis; XN; 1258C 8R 6w 81-82; 195.51mbsf. 30) Rhomboaster cuspis; XN; 1258C 8R 6w
75-76; 195.45mbsf. 31) Rhomboaster cuspis; XN; 1258C 8R 6w 70-71; 195.40mbsf. 32) Rhomboaster cuspis;
XN; 1258C 8R 6w 70-71; 195,40mbsf. 33) Rhomboaster cuspis; XN; 1258C 8R 6w 70-71; 195.40mbsf.
34) Rhomboaster cuspis; XN; 1258C 8R 6w 68-69; 195.38mbsf. 35) Rhomboaster cuspis; XN; 1258C 8R
6w 52-53; 195.22mbsf. 36) Rhomboaster cuspis; XN; 1258C 8R 6w 52-53; 195.22mbsf. 37) Rhomboaster
bramlettei; XN; 1258C 8R 6w 85-86; 195.55mbsf. 38) Rhomboaster bramlettei; XN; 1258C 8R 6w 12-13;
194.82mbsf. 39) Rhomboaster spineus; XN; 1258C 8R 6w 195.51mbsf. 40) Thoracosphaera operculata; XN;
1258C 8R 6w 110-111; 195.80mbsf.
34
APPENDIX
Fig.2.9
35
CHAPTER II
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1
1
1
1
1
1
1
2
1
2
1
1
1
1
1
3
2
1
4
1
1
1
1
1
1
1
Calciosolenia aperta
Neococcolithes protenus
Neochiastozygus substrictus
Neochiastozygus junctus
Neochiastozygus perfectus
Neochiastozygus rosenkrantzii
Neochiastozygus distentus
Zygodiscus plectopons
Lophodolithus nascens
Pontosphaera formosa
Pontosphaera sp.
Helicosphaera bramlettei
1
2
2
Fig.2.10a. Calcareous nannofossil record of the latest Paleocene to early Eocene.
36
Helicosphaera sp. 1
Ellipsolithus anadoluensis
Ellipsolithus bollii
Ellipsolithus macellus
Ellipsolithus spp.
Ellipsolithus distichus
1
1
1
2
1
2
2
1
1
2
1
2
1
1
1
1
1
5
2
8
1
5
4
7
2
1
1
3
4
1
3
1
1
1
1
2
2
4
2
2
1
4
8
1
2
3
Ellipsolithus sp.1
3
3
2
3
3
4
4
1
1
5
3
2
1
3
2
3
6
1
Clausicoccus fenestratus
7
6
2
5
4
4
1 1
12
9
8
7
5
8
13
5
2
10
13
3
1
2
1
1
1
1
1
1
1
1
Clausicoccus subdistichus
2
Chiasmolithus solitus
1
1
Chiasmolithus nitidus
Chiasmolithus consuetus
aff. Cruciplacolithus cassus
1
5
1
4
2
3
3
4
2
3
1
3
1
3
3
3
4
4
9
3
3
10
6
10
6
8
14
5
9
1
8
8
5
4
8
5
10
16
7
13
7
5
11
18
4
15
29
13
18
37
25
36
16
17
42
26
14
16
10
3
10
11
8
10
Cruciplacolithus asymmetricus
Cruciplacolithus edwardsii
Cruciplacolithus primus
aff. Cruciplacolithus cruciformis
1
1
1
Chiasmolithus bidens
6
1
4
4
1
3
4
Cruciplacolithus lapipons
Campylosphaera eodela
Campylosphaera dela
18
10
2
2
2
4
4
7
10
2
6
4
5
5
2
1
3
4
2
2
1
2
5
2
3
4
4
2
3
5
1
5
3
1
1
2
1
Ericsonia staerkeri
Ericsonia subpertusa
Coccolithus bownii
3
1
6
Coccolithus latus
1 7 9
2 10 3
6 2
1 5 8
1 8 7
4 4
1 3 8
3 5 9
3 13
8 9
2 6
3
1
4
2
1 1
2
7
2
2
3
2
1
3
Coccolithus crucis
Coccolithus pelagicus
Toweius serotinus
Toweius pertusus
Cyclicargolithus luminis
1
110
113
117
111
125
126
118
113
152
110
129
126
131
116
137
138
145
142
127
149
133
130
104
120
138
121
148
125
139
158
162
150
175
161
204
172
170
185
167
193
175
195
225
203
236
194
206
205
177
195
175
231
212
236
196
178
184
178
175
180
193
197
208
216
187
171
223
119
130
146
144
123
129
122
118
96
140
125
134
133
142
131
145
128
174
165
Umbilicosphaera? jordanii
2
1
3
3
3
113 7
122 11
106 3
87
108 2
105 2
162 6
104 1
97 3
101 2
118 1
125 1
142 2
156 2
131
135 2
136 1
121 5
140 9
142 6
129 6
128 5
157 5
149 3
134 2
142 1
120 1
137 4
123 4
91 7
88 5
101 8
85 9
85 4
68 3
82 7
92 4
75 3
77 7
79 4
71 4
85 8
60 5
69 8
69 8
73 7
76 6
65 5
91 5
80 10
79 8
65 8
61 5
56 10
74 6
81 8
69 8
76 5
97 7
88 5
70 5
73 1
94 3
90 6
88 4
86 4
77 2
140 6
106 8
98 6
98 2
101 3
115 4
93 3
110 4
138 3
100 2
114 1
115 1
130 1
133 2
133 1
125 1
127
83 5
100 5
Coronocyclus bramlettei
1
1
3
2
9
1
1
1
1
2
4
1
5
1
3
9
3
3
2
5
7
9
7
15
12
8
7
6
8
13
11
7
5
15
7
6
9
7
5
12
9
4
7
4
12
16
12
13
16
5
13
14
15
13
11
14
11
16
8
9
4
3
2
10
1
3
11
8
9
7
10
11
3
11
4
9
13
7
5
4
7
2
3
6
3
5
2
3
5
2
4
8
6
6
1
1
3
Coccolithus minimus
1
8
5
Coccolithus foraminis
2
1
2
Toweius occultatus
1
5
2
8
8
5
2
14
13
9
4
4
3
2
4
2
1
1
2
1
2
2
2
2
1
Toweius eminens
4
Toweius callosus
Toweius sp. 2 Bown, 2005
191.70
191.75
191.80
191.85
191.90
191.95
192.00
192.05
192.10
192.15
192.20
192.25
192.30
192.35
192.40
192.45
192.50
192.55
192.60
192.65
192.70
192.75
192.80
192.85
192.90
192.95
193.00
193.05
193.10
193.15
193.20
193.22
193.25
193.30
193.35
193.40
193.45
193.50
193.55
193.60
193.65
193.70
193.75
193.80
193.85
193.90
193.95
194.00
194.05
194.07
194.09
194.10
194.11
194.13
194.15
194.17
194.19
194.20
194.21
194.23
194.25
194.27
194.29
194.30
194.31
194.33
194.35
194.37
194.39
194.40
194.41
194.43
194.45
194.47
194.49
194.50
194.51
194.53
194.55
194.57
194.59
194.60
194.61
194.63
194.65
194.67
Depth (mbsf) 1258C
1258C
191.70
191.75
191.80
191.85
191.90
191.95
192.00
192.05
192.10
192.15
192.20
192.25
192.30
192.35
192.40
192.45
192.50
192.55
192.60
192.65
192.70
192.75
192.80
192.85
192.90
192.95
193.00
193.05
193.10
193.15
193.20
193.22
193.25
193.30
193.35
193.40
193.45
193.50
193.55
193.60
193.65
193.70
193.75
193.80
193.85
193.90
193.95
194.00
194.05
194.07
194.09
194.10
194.11
194.13
194.15
194.17
194.19
194.20
194.21
194.23
194.25
194.27
194.29
194.30
194.31
194.33
194.35
194.37
194.39
194.40
194.41
194.43
194.45
194.47
194.49
194.50
194.51
194.53
194.55
194.57
194.59
194.60
194.61
194.63
194.65
194.67
2
1
1
2
5
3
1
1
1
1
1
1
1
1
1
1
2
1
2
2
2
2
1
1
1
2
2
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
2
1
1
1
2
1
1
1
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
3
2
3
1
2
1
1
1
3
2
1
1
1
1
6
1
2
1
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
3
3
1
1
11
10
31
31
27
32
18
17
8
6
9
7
2
7
3
12
7
13
9
19
7
13
11
8
14
9
12
9
14
15
16
16
7
10
11
21
17
12
7
14
9
15
13
10
8
9
17
8
4
7
3
10
4
3
9
2
6
3
6
7
8
10
7
12
6
2
10
6
3
7
6
3
3
2
7
5
5
2 7
2
3
4
6
9
3
6
7
1
6
1
6
4
6
4
2
3
6
5
1
1
2
1
1
2
1
1
2
1
1
1
1
1
1
1
1
2
1
1
1
1
2
1
1
1
3
1
3
2
1
1
1
1
1
1
1
1
2
1
1
1
2
2
1
1
3
3
1
1
4
4
1
1
4
3
2
3
2
1
1
2
2
1
1
1
1
3
2
1
1
1
2
1
1
1
1
1
2
2
1
3
2
1
2
1
4
2
4
3
3
3
5
3
2
4
3
3
2
4
1
3
1
2
3
1
1
1
1
1
1
1
1
1
1
3
2
1
1
2
2
2
2
1
1
1
1
1
1
1
1
2
1
2
1
1
1
3
1
1
2
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
2
1
1
1
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
3
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
3
1
1
1
1
1
1
1
1
1
1
1
2
1 14
11
12
17
20
12
16
16
16
20
12
12
7
7
16
15
7
13
11
13
13
14
13
18
11
15
15
16
11
14
18
20
21
18
10
10
9
19
12
13
7
13
6
6
14
11
11
12
6
11
11
17
1 5
15
1 16
7
11
10
13
12
3
1 8
10
13
8
9
12
1 16
11
12
1 9
11
13
1 8
1 5
16
1 7
8
25
18
27
18
17
19
15
10
1
1
NP zones Martini (1971)
Calcareous Dinoflagellates
2
1
1
1
1
1
1
1
1
1
Coccospheres
1
1
2
1
1
4
4
1
1
Unknown species 1
Thoracosphaera operculata
Biantolithus sparsus
Rhomboaster spineus
Rhomboaster bramlettei
Rhomboaster cuspis
Sphenolithus moriformis
Sphenolithus acervus
Sphenolithus anarrhopus
Bomolithus aquilus
Bomolithus sp.
2
1
3
3
1
1
1
1
1
1
Fasciculithus billii
Fasciculithus tympaniformis
1
1
1
1
1
1
1
3
1
1
1
1
1
1
3
1
1
1
1
1
2
1
1
2
2
1
1
1
2
2
1
3
2
1
4
1
2
1
1
3
1
2
2
1
1
1
5
1
4
1
1
3
2
1
1
1
3
1
2
1
1
1
2
2
3
1
1
2
1
1
1
Fasciculithus thomasii
Fasciculithus schaubii
Fasciculithus lilianiae
Fasciculithus involutus
Fasciculithus hayii
Fasciculithus clinatus
Fasciculithus alanii
Fasciculithus spp.
Discoaster sp. 4
Discoaster sp.3
Discoaster sp. 2
Discoaster salisburgensis
Discoaster anartios
Bomolithus/Discoaster megastypus
teratoid Discoaster nobilis
Discoaster sp. 1
1
5
2
3
3
2
4
3
1
1
1
1
1
4
8
6
10
2
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
1 7
3
2
10
8
2
3
9
1
1
2
3
4
4
5
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
2
1
1
3
2
1
1
1
1
1
1
2
1
2
1
1
1
1
2
1
1
1
1
3
1
1
2
2
1
1
2
1
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Discoaster nobilis
Discoaster barbadiensis
Discoaster delicatus
teratoid Discoaster multiradiatus
Discoaster multiradiatus
Discoaster falcatus
Discoaster kuepperi
Discoaster mohleri
Discoaster mahmoudii
Discoaster lenticularis
Discoaster diastypus
Discoaster araneus
Discoaster araneus (9 rays)
teratoid Discoaster spp.
aff. Laternithus spp.
Holodiscolithus solidus
aff. Blackites virgatus
aff. Syracosphaera ? tanzanensis
Depth (mbsf) 1258C
1258C
Discoaster anartios morphotype Raffi & De Bernardi, 2008
APPENDIX
1
1
3
1
1
3
1
1
1
1
2
1
1
1
1
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
2
1
1
1
1
1
1
1
1
1
1
3
1
1
2
2
1
1
1
1
1
1
4
2
1
1
3
1
1
1
1
1
3
1
3
1
1
2
1
1
1
1
2
1
1
3
1
2
1
1
1
2
1
1
1
2
1
4
2
5
4
Fig.2.10b. Calcareous nannofossil record of the latest Paleocene to early Eocene.
37
CHAPTER II
1
3
2
1
1
1
3
1
3
2
1
1
3
2
1
1
1
1
1
1
1
3
1
1
3
4
1
1
3
1
5
4
2
1
4
1
3
8
3
4
4
4
1
2
2
1
1
1
3
1
1
1
7
1
3
1
1
1
1
1
1
1
1
2
1
4
1
1
1
5
1
1
1
2
10
4
5
1 1
1
2
1
3
1 1
1 1
1
1 1
1 1
1
1
5
1
1 3
2
1
1
2
1
3
6 5 36 2
7 13 71 8
1 6 69 2
2 7 104 5
1 1 134 4
1 6 143 2
4 6 107 4
9 7 102 8
5 8 89 13
3 7 92 9
3 9 126 10
6 10 134 3
9 7 117 13
7 7 101 10
5 6 99 11
7 8 129 7
4 14 116 8
9 9 162 8
8 8 155 8
5 5 136 14
7 7 159 13
1
1
1
1
1
1
1
1
1
1
1
1
1
2
3
2
2
1
1
1
1
2
3
1
3
1 10
13
12
14
1 7
2
1
1
1
3
1
7
2
1
2
4
6
13
21
25
12
31
26
28
40
12
24
18
10
39
21
31
43
51
40
33
61
70
80
118
72
98
102
68
57
83
80
72
40
40
70
70
70
101
47
51
97
1
1
1
1
1
1
4 15
20
1 13
13
5 9
1 17
1 10
2 18
6 19
5 6
5 10
14
2 9
19
25
2 21 1
27
29
4 32
2 36
1 20
3 18
2 25
2 22
3 22
5 25
3 11
3 12 2?
6 18
4 20
6 24
3 15
6 16
10 15
7 14
7 13
7 11
8 3
2 1
1 6
5 6
4
1
3
12 1
1
4
1
1
2
2
1
1
4
1
1
2
1
1
3
2
2
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
4
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
5
2
2
1
1
1
8
7
6
2
1
1
2
1
1
1
1
1
6
5
5
6
4
3
2
9
5
2
5
3
7
5
2
7
2
5
9
12
13
16
12
7
9
6
21
15
11
5
1
3
5
5
1
2
1
7
3
4
6
3
1
1
2
4
2
4
1
1
2
1
12
1
9
1
3
4
7
1 1
1 2
5
1
3
1
6
5
2
3
2
2
2
7
2
1
1
1
4
1
1
1
4
2
2
3
3
2
3
2
4
2
5
3
1
1
1
1
4
3
3
2
1
3
2
1
2
1
1
1
14
7
12
18
12 7
8 15
13
1 15
2 18
2 25
8
1 2 4
2
2
1 4
2
2 1
1 3
1 6
4
1 4
1
2
2
6
9
5
2
3
3
1
5
3
4
3
2
1
2
4
4
7
1
3
1
1
5
2
3
6
2
4
4
1
2
1
1
1
Neochiastozygus junctus
Pontosphaera sp.
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
2
1
2
3
1
1
4
1
1
1
1
1
1
1
1
1
3
1
3
1
1
1
1
1
1
2
1
1
1
1
1
1
1
2
3
1
1
1
1
1
1
1
15
2
5
3
3
4
1
1
1
3
1
1
2
6
1
1
1
2
2
1
1
2
1
1
1
1
1
1
3
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
Fig.2.10c. Calcareous nannofossil record of the latest Paleocene to early Eocene.
38
1
1
1
1
1
1
1
1
1
2
3
1
2
4
7
3
4
20
2
Helicosphaera sp. 1
Ellipsolithus spp.
Ellipsolithus sp.1
Umbilicosphaera ? jordanii
1
42
8
1
1
1
1
2
1
1
2
1
5
2
1
1
3
1
1
1
1
2
1
1
2
1
1
1
3
1
1
2
1
1
3
1
1
2
2
3
1
1
1
Clausicoccus subdistichus
1
1
1
aff. Cruciplacolithus cassus
1
1
1
1
1
1
1
3
1
1
aff. Cruciplacolithus cruciformis
Cruciplacolithus lapipons
Campylosphaera eodela
Campylosphaera dela
Ericsonia staerkeri
Coccolithus bownii
Coccolithus minimus
5
2
7
10
4
6
3
6
10
6
9
3
3
11
13
10
11
9
2
2
1
4
2
1
5
3
201
221
170
144
132
94
158
135
144
121
100
95
107
135
180
159
169
89
87
114
116
4
3
3
12
2
9
6
5
1
5
11
4
2
2
5
12
7
7
12
14
14
18
21
23
13
5
6
4
7
6
13
10
8
14
16
24
12
10
15
6
7
Coccolithus foraminis
Coccolithus latus
Coccolithus crucis
Coccolithus pelagicus
137
145
1 126
122
102
110
121
124
158
151
148
195
173
155
175
168
159
147
1 150
102
136
140
132
85
103
104
110
80
72
114
135
97
106
2 90
106
114
165
125
112
143
96
83
119
113
61
40
5
18
27
7
1
3 113 1
121 3
5 138 3
3 152 5
159 3
1 134 1
2 149 5
1 145 3
2 131 4
76 1
1 61 2
2 69 2
1 98 9
76 3
73
80 2
72 2
2 60 4
4 41 1
49 3
1 53 4
52 1
3 58 10
84 4
1 79
1 62 3
64 3
4 50 3
52 3
1 44 2
2 72 1
57
47 4
96 1
1 146 2
84 1
66 1
2 35 2
1 26 1
27 2
2 51 4
5 56 7
1 19 1
11 81 2
1 19 2
6 14 1
1
5
1 16 1
1 14
2
Toweius serotinus
5
Toweius pertusus
2
3
1
Toweius occultatus
2
1
Toweius eminens
2
3
Toweius callosus
194.69
194.70
194.72
194.75
194.76
194.78
194.80
194.82
194.84
194.85
194.86
194.90
194.92
194.94
194.95
194.96
194.98
195.00
195.02
195.04
195.05
195.06
195.08
195.10
195.12
195.14
195.15
195.16
195.18
195.20
195.22
195.24
195.25
195.26
195.28
195.30
195.32
195.34
195.35
195.36
195.38
195.40
195.43
195.45
195.47
195.49
195.50
195.51
195.53
195.55
195.57
195.59
195.60
195.61
195.63
195.65
195.67
195.70
195.75
195.77
195.79
195.80
195.81
195.83
195.85
195.87
195.89
195.90
195.93
195.95
196.00
196.05
196.10
196.15
196.20
196.31
196.41
196.51
196.58
196.71
196.80
Depth (mbsf) 1258C
1258C
1
1
1
2
1
1
1
3
4
1
2
1
1
1
1
1
6
1
1
1
1
1
1
1
1
1
1
1
1
1
3
1
1
2
1
3
2
2
1
6
2
5
2
2
8
7
4
1
1
3
7
7
1
8
4
4
2
1
1
1
1
2
1
1
1
1
1
1
2
1
1
2
1
2
2
3
1
1
1
1
2
2
1
2
2
3
2
1
4
3
5
2
3
3
2
6
1
7
5
5
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
2
1
5
1
1
2
1
2
2
1
1
1
1
1
1
1
2
2
2
1
1
8
1
1
2
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
2
9
4
5
4
4
6
3
2
3
1
8
3
5
7
4
6
11
2
1
6
4
4
2
4
2
1
1
1
1
2
1
2
2
1
1
1
1
1
1
2
1
1
1
1
3
1
2
1
1
1
1
1
1
2
6
7
8
2
1
1
1
2
3
2
1
4
1
2
1
1
1
?
1
1
1
1
1
1
2
4
2
1
1
1
3
5
4
1
2
1
2
2
2
4
1
2
1
1
1
2
5
1
1
2
1
1
1
1
1
4
1
3
1
1
1
1
1
1
1
1
1
1
2
1
1
8
1
1
2
1
2
1
1
1
1
2
3
1
2
2
1
1
2
2
1
1
2
1
1
1
1
1
1
1
1
2
1
1
2
1
3
1
1
1
1
1
1
5
2
1
1
1
1
1
5
1
10
5
7
4
2
5
8
1
1
1
1
1
1
2
4
2
1
2
1
2
1
2
3
1
2
2
1
1
1
1
1
1
1
1
1
1
2
2
1
1
1
1
1
1
1
1
1
1
4
2
1
1
1
2
1
1
1
1
2
1
1
1
2
2
1
3
1
4
3
1
3
3
1
1
1
3
1
7
2
1
1
1
1
2
1
1
1
3
3
2
2
1
1
1
1
1
1
1
Calcareous Dinoflagellates
Coccospheres
Unknown species 1
Biantolithus sparsus
Rhomboaster spineus
Rhomboaster cuspis
Bomolithus aquilus
3
3
4
2
14 1
11 1
14 1
19 1
8 2
6 5
8 3
13 3
19 1
12 5
6 1
9 5
17 2
10 1
23 2
19 4
19
21
17 1
11 6
16 2
12 1
14 4
21 1
15 1
15 1
30 2
31 1
25
24
19 4
17 1
14 2
26 2
8 2
12 5
16 10
8 10
4 5
11 1
13 6
6 4
5 4
5
6 1
3
1
4 3
1
2
7
7
7
5
7
5
3
4 NP10a
0
2
6
3
1
1 5
5
6
5
5
6
5
11
10
3
7
1
6
5
2
5
15
12
16
1
14
9
10
2 1
3
12
5 NP10a FO R. bramlettei
4
Aubry et al. (1995)
0 NP9b
1
1
NP9b/9a FO R. spineus & D. araneus
Aubry et al. (2000)
0
5
3
1
1
3
2
6
1
4
1
1
6
3
1
1
2
2
1
1
1
1
1
Bomolithus sp.
Fasciculithus billii
1
1
2
5
1
1
1
1
1
1
3
6
2
4
6
2
1
1
2
2
3
2
1
3
1
1
1
2
1
4
1
5
1
1
Fasciculithus hayii
Fasciculithus clinatus
Fasciculithus spp.
3
3
1
1
5
3
1
1
1
1
2
1
5
Discoaster sp. 4
1
1
1
2
2
Discoaster sp.3
Discoaster sp. 2
Discoaster sp. 1
Discoaster anartios
Bomolithus/Discoaster megastypus
teratoid Discoaster nobilis
Discoaster nobilis
teratoid Discoaster multiradiatus
1
3
5
7
4
2
3
2
1
7
2
6
3
8
1
3
Discoaster falcatus
1
1
6
Discoaster kuepperi
Discoaster mohleri
Discoaster mahmoudii
1
1
1
1 14
1 13
2 5
1
1
1
1
1
1
1
Discoaster araneus
1
1
1
1
1
5
2
6
3
5
7
1
teratoid Discoaster spp.
aff. Laternithus spp.
Holodiscolithus solidus
aff. Blackites virgatus
1
1
1
1
3
2
5
4
3
9
7
2
4
5
3
3
3
4
2
2
194.69
194.70
194.72
194.75
194.76
194.78
194.80
194.82
194.84
194.85
194.86
194.90
194.92
194.94
194.95
194.96
194.98
195.00
195.02
195.04
195.05
195.06
195.08
195.10
195.12
195.14
195.15
195.16
195.18
195.20
195.22
195.24
195.25
195.26
195.28
195.30
195.32
195.34
195.35
195.36
195.38
195.40
195.43
195.45
195.47
195.49
195.50
195.51
195.53
195.55
195.57
195.59
195.60
195.61
195.63
195.65
195.67
195.70
195.75
195.77
195.79
195.80
195.81
195.83
195.85
195.87
195.89
195.90
195.93
195.95
196.00
196.05
196.10
196.15
196.20
196.31
196.41
196.51
196.58
196.71
196.80
aff. Syracosphaera ? tanzanensis
Depth (mbsf) 1258C
1258C
Discoaster anartios morphotype Raffi & De Bernardi, 2008
APPENDIX
1
1
1
1
1
1
1
1
1
1
1
1
1
1 32
26
11
30
23
16
24
16
13
24
31
28
19
29
5
15
13
22
24
22
14
2
2
4
2
2
3
1
1
1
1
3
5
2
1
1
3
1
1
9
2
1
1
2
3
1
1
2
2
5
1
7
4
5
3
2
2
4
5
3
3
1
3
2
1
1
1
1
1
3
2
1
1
1
9
2
6
1
3
4
2
3
3
2
2
1
4
2
1
2
1
1
1
5
9
8
5
4
3
6
7
2
5
9
1
1
1
7
3
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
3
8
5
6
7
9
5
13
7
4
13
8
18
5
4
1 9
4
5
7
8
7
Intense
dissolution
PETM onset
1
1
1
NP9a
Fig.2.10d. Calcareous nannofossil record of the latest Paleocene to early Eocene.
39
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
0.55 1.86
0.54
0.54
0.54
0.59
0.57
0-57
1.86
1.85
1.86
1.86
1.85
1.84
E1
0.56 1.85
E1
E1
E1
E1
E1
E1
0.57
0.57
0.58
0.58
0.54
0.55
1.84
1.85
1.84
1.84
1.3
1.39
E1
0.56 1.41
E1
E1
E1
E1
E1
E1
0.55
0.55
0.55
0.55
0.54
0.51
1.52
1.83
1.52
1.58
1.84
1.61
E1
0.53 1.32
E1
E1
E1
E1
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
0.52
0.53
0.53
0.53
0.53
0.53
0.53
0.53
0.54
0.52
0.51
0.52
0.52
0.53
0.53
0.54
0.54
0.53
0.53
0.52
0.53
0.53
0.53
0.52
0.57
0.58
0.57
0.56
0.57
0.57
0.57
0.58
0.57
0.55
0.57
0.57
0.56
0.57
0.56
0.55
0.56
1.57
1.56
1.55
1.56
1.55
1.62
1.59
1.43
1.39
1.48
1.48
1.49
1.69
1.61
1.64
1.69
1.76
1.73
1.82
1.87
1.82
1.86
1.89
1.84
1.92
1.97
1.86
2
1.8
2
1.95
2
2
1.87
1.86
1.81
1.89
1.98
2.1
2.15
2.14
28
37
31
34
42
37
29
36
33
36
31
32
27
29
25
29
25
24
28
29
29
28
23
28
28
27
26
19
25
27
25
27
25
24
20
21
21
28
19
26
31
25
26
24
27
21
23
19
22
29
24
23
24
27
24
25
27
25
24
25
30
30
28
30
25
30
26
32
28
26
30
33
21
29
31
30
31
32
27
24
26
21
31
22
5.93E+08 7 194.65
24 -0.34
1.56E+09 8 194.67 29.6 -0.28
9.35E+08 10 194.69 18.9 -0.49
5.03E+08 6 194.70 24.6 -0.37
1.09E+09 12 194.72 23.3 -0.44
7.50E+08 9 194.75 55.6 -0.48
1.11E+09 5 194.76
31 -0.42
1.80E+09 8 194.78 33.1 -0.47
1.07E+09 8 194.80 50.3 -0.53
1.18E+09 7 194.82 18.5
-0.6
1.14E+09 7 194.84 23.2 -0.69
1.05E+09 6 194.85 49.6 -0.63
1.00E+09 5 194.86
32 -0.62
9.32E+08 6 194.90 51.9 -0.63
1.39E+09 3 194.92
31 -0.57
1.02E+09 5 194.94 28.3 -0.56
1.27E+09 5 194.95 48.1 -0.54
1.75E+09 5 194.96 18.8 -0.44
9.69E+08 3 194.98 18.9 -0.54
1.48E+09 5 195.00 39.1 -0.39
1.27E+09 5 195.02
7.8 -0.51
1.01E+09 5 195.04
24 -0.45
9.78E+08 3 195.05 21.6 -0.42
7.57E+08 4 195.06
23 -0.47
7.93E+08 3 195.08 21.3 -0.55
4.65E+08 6 195.10 17.8 -0.62
9.70E+08 4 195.12 17.4 -0.77
7.98E+08 3 195.14 17.4 -0.75
9.55E+08 4 195.15 19.4 -0.77
8.84E+08 6 195.16 17.2 -0.68
4.16E+08 3 195.18 12.5 -0.81
1.06E+09 5 195.20
17 -0.71
1.10E+09 4 195.22 15.6 -0.83
1.46E+09 5 195.24 14.5 -0.68
6.84E+08 3 195.25
17 -0.86
8.62E+08 5 195.26 30.6 -1.05
8.59E+08 2 195.28
41
0.36
6.15E+08 4 195.30 9, 5
-0.98
4.57E+08 2 195.32 1, 5 7 -1.04
8.94E+08 5 195.34
0 -1.31
9.72E+08 6 195.35 8.78 -1.25
9.23E+08 2 195.36
0 -1.38
1.02E+09 7 195.38
0 -1.77
1.59E+09 3 195.40
0 -1.25
1.59E+09 5 195.43
-1.79
8.73E+08 3 195.45 2.94 -2.82
8.81E+08 5 195.47
0 -5.97
8.76E+08 4 195.49
0 -9.55
5.40E+08 4 195.50
0 -10.61
7.26E+08 4 195.51
0 -9.31
6.53E+08 3 195.53
0 -8.99
1.02E+09 5 195.55
0 -9.41
8.38E+08 3 195.57
0
-6.3
6.85E+08 5 195.59
0 -0.91
7.60E+08 4 195.60
0 -2.12
9.09E+08 4 195.61
0 -11.3
9.31E+08 3 195.63
0 -1.82
8.73E+08 4 195.65
0 -2.42
4.31E+08 4 195.67
0 -7.47
1.23E+09 4 195.70
0 -10.53
1.29E+09 7 195.75
0 -11.11
7.63E+08 4 195.77 13.6 -11.1
7.96E+08 6 195.79
40
1
9.91E+08 6 195.80 47.8 1.22
1.11E+09 3 195.81 59.8 1.17
8.78E+08 7 195.83 61.4
1.2
9.46E+08 4 195.85 43.8 1.19
3.83E+08 5 195.87 33.3 1.11
8.24E+08 5 195.89 33.3 1.13
6.80E+08 6 195.90
43
0.98
8.73E+08 6 195.93 33.3 1.03
1.26E+09 7 195.95
42
0.95
3.55E+08 3 196.00 47.1 0.91
5.21E+08 6 196.05 38.5 0.95
6.75E+08 5 196.10 39.2 0.85
3.95E+08 8 196.15 41.8 0.78
7.96E+08 6 196.20 41.9 0.78
6.62E+08 7 196.31 40.3
5.99E+08 5 196.41 42.8
0.8
5.84E+08 4 196.51
445
0.38
5.03E+08 5 196.58 38.3 0.37
3.89E+08 4 196.71 41.7 0.42
8.99E+08 4 196.80
40
0.76
5.29E+08 4
-3.16
-3.06
-3.25
-3.04
-2.91
-2.9
-2.9
-2.85
-2.92
-2.91
-3.19
-3.01
-3.02
-3.17
-3.13
-3.1
-3.08
-3.04
-3.17
-2.89
-3.09
-3.03
-2.92
-3.06
-3.12
-3.26
-3.11
-3.13
-3.07
-3.07
-3.02
-3.05
-3.11
-2.96
-3.32
-3.38
-2.48
-2.89
-2.79
-3.11
-3.07
-3.17
-3.16
-3.11
-3.16
-2.26
-1.58
-0.3
1.2
-0.45
0.33
-0.67
-1.97
-1.7
-1.09
-3.23
-1.78
-1.45
0.47
-1.96
-3.1
-2.98
-2.76
-2.74
-2.69
-2.69
-2.63
-2.59
-2.74
-2.72
-2.67
-2.74
-2.71
-2.71
-2.74
-2.76
-2.8
-2.66
-2.72
-2.66
E2-E3
E2-E3
E2-E3
E2-E3
E2-E3
E2-E3
E2-E3
E2-E3
E2-E3
E2-E3
E2-E3
E2-E3
E2-E3
E2-E3
E2-E3
E3
E2-E3
E3
E2-E3
E3
E3
E2
E2
E3
E3
E3
E3
E3
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
E1
0.64
0.61
0.63
0.62
0.63
0.62
0.61
0.71
0.72
0.72
0.62
0.61
0.72
0.96
0.8
0.62
0.63
0.86
0.68
0.91
0.73
0.92
0.94
0.82
0.9
0.99
0.6
0.6
0.58
0.59
0.58
0.59
0.59
0.59
0.58
0.59
0.59
0.59
0.59
0.58
0.59
0.58
0.55
0.56
0.55
0.56
0.57
0.56
0.5
2.16
2.17
2.18
1.98
2.19
1.98
2.2
2
2.09
2.01
1.97
2.48
2.48
2.41
2.18
2.47
2.14
2.5
2.1
1.18
1.19
0.52
0.45
1.72
1.36
1.39
0.86
1.95
1.85
1.9
1.9
1.9
1.9
1.89
1.88
1.91
1.94
1.94
1.89
1.9
1.94
1.82
1.74
1.78
1.66
1.79
1.8
1.72
1.67
321
335
341
354
355
372
352
325
349
391
397
319
312
348
384
330
344
387
354
346
349
328
342
325
359
337
349
384
367
344
350
337
375
334
349
377
369
340
394
340
286
353
348
291
331
304
126
116
22
76
62
12
6
5
0
3
6
10
6
5
0
0
377
406
334
357
363
331
360
332
339
322
325
323
331
331
343
371
352
341
335
331
351
26
23
34
28
30
29
27
23
34
29
30
26
32
29
30
27
25
31
31
30
30
30
32
29
30
36
29
29
32
32
35
34
28
31
30
31
28
32
29
33
30
29
32
29
31
43
26
25
10
27
16
5
4
2
0
2
5
5
4
2
0
0
32
21
26
30
32
24
25
23
30
28
21
28
25
22
26
26
20
25
23
21
25
3.65E+08
5.40E+08
8.17E+08
6.68E+08
4.37E+08
6.00E+08
6.50E+08
5.05E+08
6.45E+08
6.93E+08
6.40E+08
6.02E+08
6.01E+08
3.35E+08
4.20E+08
2.81E+08
4.48E+08
6.13E+08
3.53E+08
3.37E+08
2.52E+08
2.91E+08
3.30E+08
3.84E+08
3.35E+08
3.78E+08
4.69E+08
5.01E+08
2.60E+08
3.05E+08
2.48E+08
1.93E+08
4.89E+08
3.25E+08
3.64E+08
3.09E+08
5.28E+08
2.01E+08
2.61E+08
2.72E+08
6.85E+08
2.72E+08
2.20E+08
8.46E+07
2.00E+08
8.69E+07
3.72E+07
3.43E+07
6.50E+06
2.25E+07
1.83E+07
3.49E+06
1.77E+06
1.48E+06
0.00E+00
8.87E+05
1.77E+06
2.96E+06
1.77E+06
1.48E+06
0.00E+00
0.00E+00
1.34E+09
1.12E+09
1.97E+09
1.67E+09
1.19E+09
8.38E+08
6.79E+08
5.35E+08
1.04E+09
4.33E+08
3.56E+08
5.73E+08
5.34E+08
1.01E+09
1.90E+09
1.10E+09
1.11E+09
6.43E+08
8.03E+08
6.99E+08
1.11E+09
Discoaster diversity
2.13
2.14
2.16
2.15
2.15
2.15
2.15
2.16
2.15
2.15
2.16
2.13
2.16
2.13
2.17
2.16
2.16
2.17
2.18
2.19
2.17
2.17
2.18
2.16
2.15
2.17
2.18
2.17
2.16
2.17
2.18
2.18
2.19
2.18
Absolute Abundance
0.56
0.55
0.56
0.57
0.57
0.57
0.57
0.58
0.57
0.57
0.55
0.59
0.51
0.56
0.51
0.62
0.61
0.6
0.61
0.62
0.64
0.62
0.63
0.62
0.61
0.61
0.62
0.63
0.64
0.63
0.62
0.62
0.62
0.63
Species richness
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2-E3
E2-E3
Counted Individuals
Preservation index
δ18O
δ13C ‰ (V-PDB)
Carbonate content (%)
Depth (mbsf)
Discoaster diversity
Absolute Abundance
Species richness
Counted Individuals
341
351
327
318
380
347
387
346
363
333
346
332
340
347
344
346
344
355
339
367
343
341
331
350
349
336
350
342
334
329
324
335
348
329
332
321
339
347
309
353
329
354
335
340
376
325
348
336
329
352
324
367
331
371
343
328
336
325
340
348
334
353
359
380
337
327
363
350
344
330
325
342
332
335
335
325
377
351
331
336
363
316
355
322
4
3
5
6
6
7
5
3
6
5
5
8
5
9
7
8
7
7
7
8
7
6
7
9
8
10
12
10
11
10
14
9
7
10
8
9
6
8
7
10
9
8
8
7
8
5
2
5
8
4
1
1
4
2
2
2
3
2
2
2
2
4
2
2
2
3
2
2
3
2
1
Fig..2.11. Geochemistry and calcareous nannofossil diversity indices (1258C).
E1
0.6
2
0.61 2.2
0.61 2.25
0.59 2.1
0.56 1.95
0.61 2.2
0.59 1.96
0.61 2.1
0.59 1.94
0.58 1.93
0.56 1.92
0.57 1.92
0.57 1.92
0.56 1.8
0.55 1.91
0.59 1.87
0.56 1.86
0.55 1.87
0.56 1.87
0.56 1.85
0.55 1.86
Shannon Index
E1
E1
E1
E1
E1
E1
Evenness
E1
Shannon Index
-2.47
-2.41
-2.44
-2.37
-2.47
-2.51
-2.43
-2.65
-2.5
-2.43
-2.6
-2.49
-2.59
-2.57
-2.59
-2.47
-2.46
-2.49
-2.48
-2.53
-2.3
-2.37
-2.27
-2.41
-2.55
-2.28
-2.44
-2.26
-2.2
-2.2
-2.35
-2.35
-2.46
-2.41
-2.44
-2.5
-2.5
-2.42
-2.52
-2.65
-2.71
-2.74
-2.74
-2.98
-2.77
-2.61
-2.37
-2.52
-2.68
-2.55
-2.7
-2.67
-2.55
-2.58
-2.59
-2.59
-2.57
-2.58
-2.72
-2.7
-2.91
-2.98
-2.94
-2.85
-2.86
-3
-2.97
-2.95
-3.13
-3.02
-3.05
-3.07
-3.09
-3.1
-3.16
-3.03
-3.11
-3.19
-3.04
-3.14
-3.21
-3.26
-3.28
-3.2
Evenness
1.17
1.01
0.93
1.02
0.99
0.9
1
1.12
1.14
1.07
1.05
1.01
1.01
0.97
1.16
1.11
0.98
0.79
0.83
0.81
0.89
0.86
0.98
0.83
0.87
0.86
0.94
0.93
0.82
0.75
0.72
0.72
0.77
0.81
0.72
0.69
0.7
0.79
0.96
1.17
1.04
0.93
0.94
0.83
0.63
0.44
0.23
0.28
0.21
0.25
0.3
0.31
0.16
0.19
0.19
0.14
0.27
0.26
0.17
0.4
0.45
0.48
0.43
0.46
0.5
0.4
0.43
0.42
0.23
0.14
0.08
0.06
0.04
0.15
0.11
0.04
0.06
-0.06
-0.28
-0.26
-0.26
-0.3
-0.15
-0.26
Preservation index
δ O
δ C ‰ (V-PDB)
18
40
52
53
49
45
44
51
52
41
39
55
41
42
42
37
37
39
44
46
49
45
50
52
53
46
49
46
50
52
0.5
51
49
45
56
50
50
52
48
39
37
39
28
38
30
37
42
44
50
44
47
42
40
47
44
44
50
41
30
42
34
36
41
27
26
47
30
29
47
26
27
50
25
23
42
26
16
41
14
15
39
16
20
21
12
16
13
191.70
191.75
191.80
191.85
191.90
191.95
192.00
192.05
192.10
192.15
192.20
192.25
192.30
192.35
192.40
192.45
192.50
192.55
192.60
192.65
192.70
192.75
192.80
192.85
192.90
192.95
193.00
193.05
193.10
193.15
193.20
193.22
193.25
193.30
193.35
193.40
193.45
193.50
193.55
193.60
193.65
193.70
193.75
193.80
193.85
193.90
193.95
194.00
194.05
194.07
194.09
194.10
194.11
194.13
194.15
194.17
194.19
194.20
194.21
194.23
194.25
194.27
194.29
194.30
194.31
194.33
194.35
194.37
194.39
194.40
194.41
194.43
194.45
194.47
194.49
194.50
194.51
194.53
194.55
194.57
194.59
194.60
194.61
194.63
Carbonate content (%)
Depth (mbsf)
CHAPTER II
APPENDIX
Chapter III
Geochemical evidence for environmental
perturbations during the Paleocene-Eocene
thermal maximum from the equatorial Atlantic
41
CHAPTER III
42
INTRODUCTION
Chapter III: Geochemical evidence for environmental perturbations during the
Paleocene-Eocene thermal maximum from the equatorial Atlantic
Christian Joachim1*, Jörg Mutterlose1, Peter Schulte2 & Hans-J. Brumsack3
Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität Bochum, Universitätsstraße 150,
D-44801Bochum, Germany ([email protected]).
1
2
GeoZentrum Nordbayern, Universität Erlangen, Schlossgarten 5, D-91054 Erlangen, Germany.
Institute for Chemistry and Biology of the Marine Environment ICBM, Oldenburg University, P.O.
Box 2503, D-26111 Oldenburg, Germany.
3
*Corresponding author
E-mail address: [email protected] (C. Joachim)
(This manuscript has been submitted for publication to Chemical Geology)
Abstract:
Changes in continental runoff, ocean productivity and oxygenation are necessary to constrain
the environmental magnitude of the Paleocene-Eocene thermal maximum (PETM), a transient
warming event about 55Ma. Here, we reconstruct changes of detrital flux, productivity proxies and
paleoredox conditions across the PETM in the tropical Western Atlantic (ODP Leg 207, Demerara
Rise) by a set of stable isotope and major and minor element geochemical data. The PETM record
of Demerara Rise shows a pronounced and sharp lithologic change from calcareous chalks to
laminated, clay-rich beds present in several drill sites across a depth transect. The typical stable
isotope pattern anomaly across the PETM from the deepest site 1258 is disturbed, since the carbon
isotopes show a negative anomaly with values as low as -10‰ and oxygen isotopes reveal a positive
excursion of 1.5‰. The K/Al ratios suggest a change in provenance or more intense weathering in
the hinterland. Barium shows a massive decrease of plankton productivity during the early stage of
the PETM. The Mn/Al ratios and bulk Mn enrichment factors (EF) show a substantial drop during
the PETM onset, followed by a gradual recovery to pre-event values. In contrast to the depletion of
Mn, other typically redox-sensitive elements (e.g., V, Cr, Co) or element/Al ratios show no certain
changes across the event. These data suggest, that paleoenvironmental conditions were probably not
oxygen-limited during the PETM.
Keywords: PETM, geochemistry, redox-conditions, productivity-indicators, ODP/IODP
3.1. Introduction
The Paleocene-Eocene thermal maximum (PETM; ~55Ma) is the most prominent of several
hyperthermal events during the Paleocene - Early Eocene period (e.g. Thomas et al., 2000; Zachos
et al., 2001). The hyperthermal events are characterised by short periods of negative δ13C carbon
43
CHAPTER III
isotope excursions (CIEs), implying major perturbations of the global carbon cycle and higher
global temperatures.
The potential causes of the hyperthermal events, including the PETM, are controversial. One
reason for the rapid warming during the PETM may be a sudden release of about 1500 to 2000Gt
of methane, derived from decomposing gas hydrate reservoirs (Dickens et al., 1995; Dickens et al.,
1997; Dickens, 2000). Another possible or additional triggering mechanism is the release of carbon
from permafrost and peat in Antarctica during warm periods, which coincide with high eccentricity
and obliquity, and therefore might also explain the following Eocene hyperthermal events (ETM 2
& ETM 3) (DeConto et al., 2012). Beyond the severe perturbation of the carbon cycle, the PETM
is characterised by extreme temperatures (e.g. Kennett & Stott, 1991; Sloan & Pollard, 1998;
Röhl et al., 2000) over 20 to 220ka (Farley & Eltgroth, 2003; Murphy et al., 2010) and a benthic
foraminifera extinction event (BFEE) (Kennett & Stott, 1991). Several parameters inherent to
the PETM (e.g. warming, water-column stratification, and enhanced fluvial discharge) may have
contributed to the development of anoxia and increased the burial efficiency of organic carbon
by reducing water column oxygenation (e.g. John et al., 2008; Schulte et al., 2011). Variations of
redox conditions during the PETM have recently become a focus of research to constrain the spatial
and water depth-dependent pattern of warming, carbon input, and O2 deficiency in the global
ocean (e.g. Chun et al., 2010; Nicolo et al., 2010). Results from the southern Pacific suggest that
intermediate waters became hypoxic (defined by Levin, 2003, to contain <0.01mol/m3 dissolved
O2) concomitant to the carbon isotope excursion (Nicolo et al., 2010). Manganese depletion and
uranium enrichment in bathyal sediments from the Walvis Ridge indicate lower dissolved oxygen
content during the PETM (Chun et al., 2010).
The current study presents a broad geochemical record of bulk samples obtained from ODP
Leg 207, Site 1258C Demerara Rise, an equatorial location in the Atlantic. Material from the same
location has previously been used for detailed studies on calcareous nannofossils (Jiang & Wise,
2006; Mutterlose et al., 2007, chapter II) with implications for paleoproductivity and possible
surface water acidification. Our interest is focussed on paleoproductivity data, derived from barium
and phosphorus concentrations (or element ratios), the variation of bottom water oxygen levels
and potential changes in detrital flux or provenance possibly related to changes in the continental
runoff, which have not been addressed before for an equatorial setting like site 1258C.
3.2. Material and methods
3.2.1. Section and material
This study has been performed on 70 samples from ODP Site 1258C, Leg 207 Demerara Rise,
~380km off the coast of Suriname, South America (9°25’N, 54°45’W) (Fig. 3.1). The 1.73m thick
interval studied here has been retrieved from a depth of 196 to 194.27 mbsf. The current water
depth at this site is 3192.2m (Erbacher et al., 2004), the paleo-latitude was 4°N, with a lowerbathyal paleo-water depth. The average sedimentation rate was 1.5cm/ka (Erbacher et al., 2004).
44
MATERIAL & METHODS
The investigated interval therefore covers approximately 208ka. The duration of the basal PETM
clay layer is 70 to 80ka (Röhl et al., 2000; Farley & Eltgroth, 2003), the total duration of the PETM
is 170ka (Röhl et al., 2007). This geochemical study is paralleled by a detailed carbon and oxygen
isotope record, obtained on the same bulk rock samples. The δ13C record is crucial for establishing
the framework for the PETM intervals. Based on the course and shape of the δ13C isotope curve
(Bowen et al., 2006), the PETM interval can be subdivided into three units (from bottom to top):
An early peak phase with the most negative δ13C values (195.77–195.55mbsf ), a subsequent body
(=basal clay layer), beginning when δ13C values reach their minimum, characterised by continued
increases in global temperature and slow dilution of oceanic acidity (Bowen et al., 2006) (195.77195.22mbsf ), and a final recovery interval to a state in the earliest Eocene that was, in many ways,
similar to that of the late Paleocene (Bowen et al., 2006) (195.20-194.60mbsf ). At various sites,
the peak phase is characterized by a distinctive clay horizon with abundant kaolinite (Gibson et al.,
1993). The pre-PETM of Site 1258C is characterised by light greenish gray nannofossil chalk with
clay and foraminifers. The lowest part of the body is homogeneous and has no apparent internal
Fig. 3.1: Paleogeographic reconstruction (55 Ma) showing location of Demerara Rise and other important
PETM sites (reconstructed from http://www.odsn.de).
features, while the uppermost 10cm show isolated burrows (Site 1258C visual core description).
The recovery interval consists of bioturbated clayey nannofossil chalk.
3.2.2. Methods
Stable isotope analysis (δ13Cbulk, δ18Obulk) of all samples >20% CaCO3 was carried out by using a
Gasbench II coupled with a Finnigan Delta S mass spectrometer at the Department of Geology,
Mineralogy and Geophysics, Ruhr-University Bochum. All samples with carbonate contents <20 %
were analysed with respect to δ13Cbulk and δ18Obulk, using a Finnigan MAT 251 mass spectrometer in
combination with a Carbo Kiel device.
The X-ray fluorescence (XRF) geochemical analyses were carried out at ICBM Oldenburg
(Department of Microbiogeochemistry). For XRF analysis (Philips® PW 2400 X-ray spectrometer),
45
CHAPTER III
600mg of sample powder were mixed with 3600mg of a 1:1 mixture of dilithiumtetraborate
(Li2B4O7) and lithium-metaborate (LiBO2), or with 100% dilithiumtetraborate for carbonate-rich
samples, preoxidized at 500°C with NH4NO3 (p.a.) and fused to glass beads. Total sulphur (TS) and
total carbon (TC) were analysed using an ELTRA® CS-500 IR-analyser. Procedures and accuracy
of the methods were checked with international and in-house reference materials (Prakash Babu
et al., 1999; see also Appendix A in Hetzel et al., 2009). The investigated material is stored at the
Department of Geology, Mineralogy and Geophysics, Ruhr-University Bochum.
3.3. Results
3.3.1. Stable isotope geochemistry
The lowermost 101cm (196.80 to 195.79mbsf ) show stable δ13Cbulk values around +1‰ (Fig.
3.2). This interval is assigned to the pre-PETM interval. The subsequent 22cm (195.77 to 195.55
mbsf ), here referred to as peak phase, is marked by an unusual sharp decline of the δ13Cbulk data up
to -11‰. Besides this extreme negative values throughout this phase, the δ13Cbulk values vary from
-2‰ to 1‰. The third interval (body), including the peak phase, is 55cm thick (195.77 to 195.22
mbsf ), shows an increase to -1‰. The fourth and final (recovery phase) is marked by a further
increase to δ13Cbulk data to essentially stable pre-event values of around +1‰.
The oxygen isotope record shows stable values of ~ -2.5‰ in the pre-PETM. Concomitant
to the occurrence of low δ13Cbulk values, the δ18Obulk record shows positive shifts to a maximum of
+1‰ in the peak phase. During the body and the early recovery interval values are at around -3‰,
before they return to pre event values of -2.5‰.
ODP Leg 207,
Core1258C -12
-10
-8
δ13C ‰ (V-PDB)
-4
-6
-2
0
2
-4
δ18O ‰ (V-PDB)
0
-2
Intervals
2
Nannofossil events
Teratoid
Discoasters
192
Post-PETM
193
+ Toweius
- Coccolithus
- Toweius
+ Coccolithus
Paleocene
NP9a
PETM
Body
Depth (mbsf)
Eocene
NP9b
NP10a
194
195
„Normal“ conditions
Recovery
„Excursion“ taxa
Discoaster araneus
teratoid Discoasters
+Temperature
- Productivity
Peak phase
CCD-shoaling
Initial warming phase
196
Pre-PETM
Fig. 3.2: Stratigraphic framework, core photo, δ13Cbulk and δ 18Obulk chemostratigraphy, PETM intervals and
calcareous nannofossil events (of chapter II) vs. depth of the Demerara Rise core [Ocean Drilling Program
(ODP) Leg 207, 1258C]. The core photo shows minor disruptions, indicated by red stripes. The lowermost
part of the PETM body contains three horizons, influenced by early diagenesis during the peak phase with
unusual low isotopic values. Calcareous nannofossil events are taken from the same section.
46
RESULTS
3.3.2. Major elements
Marine sediments essentially consist of mixtures of terrigenous material (mostly clays), carbonate,
and biogenic silica. The relative proportion of these major components is easily visualized in a
ternary diagram with Si, Al, and Ca at the corners (Brumsack, 1989; Fig. 3.3). The average shale
data point (Wedepohl, 1971) is plotted for comparison. The straight lines with numbers refer to the
respective Si/Al weight ratios. The samples from Demerara Rise comprise clay-carbonate mixtures
with major contributions of excess silica, here referred to as “bio-silica”. We assume that at most
only small amounts of quartz are present in this lower slope setting.
Fig. 3.3: Evolution of the major components during the different stages of the PETM compared to average
shale of Wedepohl (1971). The lines indicate the respective Si/Al weight ratios.
The depth distribution of the major components terrigenous detritus, carbonate, and biosilica, indicates the almost complete decline in carbonate and bio-silica during the peak phase
(Fig. 3.4). Likewise the terrigenous fraction exceeds 85%, which is reflected in the presence of a
clay layer. In general, during the pre-PETM interval carbonate contents average around 48% (see
Tab. 1), then drop to almost zero in the peak phase, increase to 10% in the body and attain levels
of ~29% in the recovery, still significantly below pre-PETM values. A similar trend is seen for the
47
CHAPTER III
calculated bio-silica values, which are high in the pre-PETM interval (24%), then drop to 4% in
the peak phase, increase to 10% in the body and almost reach the pre-PETM levels in the recovery
(22%). As mentioned above the excess silica calculated here comprises both, bio-silica and quartz.
The depth distribution of terrigenous detritus forms a mirror image of the carbonate plus bio-silica
distribution with moderate values of 27% in the pre-PETM interval, 92% in the peak and 79% in
the body and finally 48% in the recovery phase. Pyrite contents are generally low, except for some
194.4
terrigenous
carbonate
opal
depth (mbsf)
194.9
195.3
S-rich intervals, which probably are
of diagenetic origin. Barite forms a
common minor component. The
organic carbon contents are low
(0.12%) throughout the investigated
interval.
In the following we will briefly describe
specific major and minor element
ratio changes with depth. We will
first concentrate on elements, which
somehow reflect changes in provenance
or weathering. We will continue with
productivity-related elements and
briefly discuss elements significantly
affected by diagenesis.
195.8
0
20
40
60
80
100
% fraction
Fig. 3.4: Distribution of major components (terrigenous, carbonate
and opal) during the investigated interval in percentage.
3.3.3. Elements related to changes in provenance or weathering
In Fig. 3.5a and b the alkali elements are plotted versus depth. There is a dramatic decrease in Na/
Al and K/Al ratios from the pre-PETM interval to the peak phase. The trace metal Rb shows a
rather similar trend (Fig. 3.5c) with lowest values in the peak phase followed by a slow return to prePETM values in the body and recovery phase. The K/Rb ratio (Fig. 3.5d) is low in the peak phase as
well and returns to higher values in the body. Titanium and Zr are as well elements suitable for
48
Fig. 3.5: Elements related to changes in provenance or weathering. The core photograph and meters below seafloor (mbsf ) are shown on the left. The PETM onset and
recovery as well as three ash layers are indicated in the figure.
RESULTS
49
CHAPTER III
depicting changes in provenance and possibly weathering (see Fig. 5e and f ). In contrast to Na,
K and Rb, Ti/Al and Zr/Al are lowest in the body and then slowly increase, but do not reach prePETM values again. We observed a dramatic decrease in V (Fig. 3.5h) at the onset of the peak
phase, followed by a continuous return to pre-PETM values in the following course of the event.
For several element ratios some peaks occur in the section investigated, which in our view
document former ash layers. We have highlighted these presumable ash layers by a darker grey
colour. Ash layers may be important for early or late diagenetic processes, because they are likely
places for pyrite formation.
3.3.4. Elements related to bio-productivity
As already shown in Figures 3.3 and 3.4, the PETM peak phase is characterised by an almost
complete disappearance of carbonate and bio-silica. The dramatic loss in carbonate is seen in Fig.
3.6a, where Ca/Al ratios are high in the pre-PETM interval and essentially drop to values well
below average shale (see Table 2). In the body and recovery phase Ca/Al slowly increases again,
but does not attain pre-PETM values. The alkaline earth element Sr essentially shows the same
trend (Fig. 3.6b) because it is a common minor constituent in the carbonate phase. The element
Mn is also closely associated with the carbonate phase (Fig. 3.6c), most probably as overgrowths
on carbonate tests. In the carbonate-free peak phase Mn/Al ratios are extremely low (see Table 2)
compared to average shale and the adjacent layers. Such low Mn/Al ratios are only possible in a
low-oxygen environment. Therefore here Mn must be regarded as a paleoenvironmental proxy
documenting the reducing conditions prevailing in the peak phase. It is worthy to mention that
the decline in carbonate-associated element ratios starts slightly before the onset of the CIE. Mg/
Al Like for carbonate a strong decline is seen for Si/Al before the onset of the CIE (Fig. 3.6e). In
the pre-PETM interval excess silica contents (are equivalent to bio-silica) average 24% (see Table
1), drop to 4% in the peak phase. The Si/Al ratios slowly increase again in the body and peak phase,
but never attain pre-PETM values in the section studied here.
The element Ba is often regarded as a productivity proxy (e.g. Schmitz & Pujalte 1997).
The sediment section investigated is indeed characterised by high Ba/Al ratios way above average
shale values (Table 1). The depth distribution of Ba/Al (Fig. 3.6f ) shows some interesting trends:
A strong decline is seen in the pre-PETM interval with lowest values attained in the early stages
of the peak phase. Still within the peak phase Ba/Al increases again to almost pre-PETM levels
and stays high throughout the remaining section. For P/Al a similar trend is seen (Fig. 3.6g) with
lowest values in the first part of the peak phase. The element Y (Fig. 3.6h) closely follows P and is
incorporated into apatite.
50
3.3.5. Elements affected by diagenesis
Fig. 3.6: Elements related to bio-productivity.he core photograph and meters below seafloor (mbsf ) are shown on the left. The PETM onset and recovery, as well as three
ash layers are indicated in the figure.
RESULTS
51
CHAPTER III
The elements mentioned so far are only to a minor degree affected by diagenesis. By contrast, peaks
in Fe/Al-ratios (Fig. 3.7a) document the mobility of this element during early diagenesis. Most of
the Fe peaks are associated with S enrichments and reflect the presence of pyrite. Nevertheless Fe/
Al ratios are low compared to average shale (Table 2).
The Zn/Al distribution (Fig. 3.7b) is dominated by high values in the pre-PETM phase. We
assume that this pattern is not directly related to the PETM and reflects later diagenetic fixation of
this element in microenvironments with trace amounts of hydrogen sulphide. For Cu (not shown
here) the same is true.
The elements Co and Ni (Fig. 3.7c and d) exhibit a rather similar pattern, which most likely
is related to the redox change mentioned before when the element Mn was discussed (see previous
chapter). Distinct peaks in Co/Al and Ni/Al are seen at the early stages of the body. Most likely both
elements are trapped as sulphides, even though a correlation with S is not evident. These sulphides
seem to form in close vicinity to the presumed ash layers as well.
3.4. Discussion
3.4.1. Stable isotopes
Most unusual are the negative δ13Cbulk data of -10‰ V-PDB, occurring in three horizons within the
peak phase (195.77 to 195.70mbsf, 195.61 mbsf and 195.55mbsf ). In comparison to the other two
ODP Sites of Demerara Rise, which cored the PETM interval, Site 1258C is characterised by three
horizons with very negative δ13Cbulk data (Fig. 2). The unusual δ13Cbulk and δ18O values are most
probably caused by the very low carbonate contents of the samples. Similar, exceptionally strong
negative δ13Cbulk values (-10‰ V-PDB) have been described from a PETM site in the Caribbean
(Site 999B) (Bralower et al., 1997). According to Bralower et al. (1997), these low carbon isotope
values are the result of early diagenesis at or close to the seafloor. At the Caribbean Site 999 the
PETM shows an irregular, sub-horizontal base of the claystone, suggesting diffuse dissolution of the
upper few cm of seafloor carbonates.
3.4.2. Major elements
Calcium carbonate: In the deep-sea, the PETM is often marked by clay-rich condensed intervals
caused by dissolution of carbonate (Murphy et al., 2010). Compared to the maximum of a ~10cm
thick deep-sea record from Walvis Ridge (ODP Leg 208, Site 1266C, 3798m water depth) (Zachos
et al., 2005), the dissolution horizon in ODP Site 1258C has an expanded thickness of 55cm (Fig.
3). A timescale for the PETM at ODP Site 1266 suggests a duration for the zero carbonate layer of
35 ka and an increase in carbonate for ~165ka (Murphy et al., 2010). At Site 1258C on Demerara
Rise the sedimentation rate of 1.5cm/ka (Erbacher et al., 2004) and a thickness of 26cm with a
carbonate content <1 suggest a duration of 39ka for the zero carbonate layer. The main difference,
however, is the recovery of the carbonate content at the two sites. At 1266C values recover quickly
52
Fig. 3.7: Elements affected by diagenesis. The core photograph and meters below seafloor (mbsf ) are shown on the left. The PETM onset and recovery, as well as three
ash layers are indicated in the figure.
DISCUSSION
53
CHAPTER III
to half the pre-PETM, then rise more gradually to the pre event level. The recovery at Demerara
Rise is slower and more gradual. The Carbonate deposition during the PETM is inhibited by
dissolution, limited by decreased bioproductivity or a combination of both.
Silica concentrations increase at the PETM onset, mostly due to the low carbonate contents.
The detrital elements Al, Ti and Fe show the same pattern. The source of these elements in marine
sediments are mainly clay minerals, originating from tropical lateritic weathering of silicate rocks.
More diagnostic than element concentrations are element ratios, because in this case dilution effects
due to varying carbonate contents are compensated (Brumsack, 2006). The lower Si/Al ratio in
the peak phase, however, indicates a decrease in biogenic Si, which strongly parallels the carbonate
profile. Like the Calcium carbonate concentration, the SiO2 deposition is decreasing in the event.
Causes for the decreasing SiO2 deposition are either dissolution, decreasing bioproductivity of
siliceous microfossils or both effects.
Sulphur values show values of around ~1.5% during the event. Cenozoic sediments from
the Atlantic Ocean have an average sulphur content of 0.24% (Brumsack & Lew, 1982). Most
of the sulphur of marine sediments, which exceeds 0.1%, must be derived from in situ bacterial
sulphate reduction (Wedepohl, 1971). Under marine euxinic conditions sufficient H2S is produced
that the dominant control on pyrite formation is availability of reactive iron minerals (Berner,
1984).
3.4.3. Elements related to changes in provenance or weathering
The almost parallel behavior of the alkali elements Na and K lets us suggest, that these transitions
are either related to a provenance change or a different degree of weathering on the hinterland. The
Na/Al ratio is rather high compared to average shale (see Table 2), but values are not corrected for
sea salts. Porosity and therefore pore water contents are significantly elevated in opal-rich sediments
and this may be the reason why values are high in the pre-PETM interval and the recovery. But
this effect cannot have an influence on K/Al, since K concentration in seawater is significantly
lower than that of Na. K/Al ratios are much lower than average shale especially in the peak phase.
Besides changes in provenance this may as well reflect more intense weathering in the hinterland.
The changes in K/Al and Mg/Al (Fig. 5b & 6d) may result from a change in clay mineralogy. Illite
and mica are the primary source of potassium (Yarincik et al., 2000), whereas Mg is frequently
included in chlorite (Turgeon & Brumsack, 2006). The Mg/Al record does not show significant
changes during the PETM at Demerara Rise, suggesting a stable chlorite supply. The K/Al record,
however, indicates a decrease in illite and mica supply concomitant with the CIE onset, in the basal
PETM clay layer.
The main sources of the detritus-sensitive elements are sediments transported from the
continental hinterland either by river runoff or as eolian dust. The elevated and strongly varying
values of Ti/Al and Zr/Al in the peak phase must be related to the fact, that this represents an
almost pure clay layer. Presumably sedimentation rates were low during this interval and an eolian
54
DISCUSSION
contribution might possibly explain the data. Likewise slightly stronger currents would lead to
winnowing and the preferential accumulation of heavy minerals. But here as well a provenance
change may be indicated, because Ti/Zr ratios increase from pre-PETM values throughout the peak
and body and remain high thereafter (Fig. 3.5g). V does not seem to be affected by redox changes
or diagenesis and therefore may as well be used as an indicator for provenance (Fig. 3.5h). The 4%
excess SiO2 during the peak phase are, due to the absence of siliceous microfossils, eventually related
to higher eolian input - or lower sedimentation rate during constant eolian input of quartz.
The hinterland geology of Suriname is dominated by the Guiana Shield, a Precambrian
craton, consisting of Proterozoic and late Archean greenstone belts, basalts, felsic volcanics (Gibbs,
1987) The coastal area is dominated by Paleogene and Neogene sediments (Wong, 1989). More
humid conditions during the PETM are reported from several locations worldwide: Enhanced
terrestrial weathering and continental runoff are reported from the Weddell Sea (Antarctica) during
the PETM (Kelly et al., 2005). A brief increase in kaolinite at the inception of the CIE suggests a
temporary increase in year-round precipitation in Antarctica, in response to an increased continent
to ocean temperature gradient (Robert & Kennett, 1994). Also, Schmitz & Pujalte (2007) report
a dramatic increase in seasonal rain and an increased intra-annual humidity gradient from the
Tremp-Graus basin (Spain). Results from the Dababiya section, Egypt suggest a major increase in
phyllosilicate abundance and changes in detritus-sensitive trace elements, enhanced fluvial input,
erosion of coastal low lands and deposition during low or slightly rising sea level (Schulte et al.,
2011). Only the higher Ti/Al levels of Demerara Rise and the Dababiya section are similar. The
bulk ratios of K/Al, Na/Al and the increase in the terrigenous fraction indicate intense weathering
due to increased precipitation and higher continental runoff during the peak phase of the PETM.
A changing origin of the material is also possible. A higher continental runoff could have lead to
reduced surface water salinity (e.g. Zachos et al., 2003; Tripati & Elderfield, 2004; Sluijs et al.,
2006) and higher stratification (e.g. Kaiho et al., 1996; Petrizzo 2007; Dypvik et al., 2011).
3.4.4. Elements related to bioproductivity
High concentrations of barium are generally interpreted as an indicator for higher paleoproductivity
(Goldberg and Arrhenius, 1958; Dehairs et al., 1980; Lea & Boyle, 1990; Dymond et al., 1992;
McManus et al., 1998; Gingele, et al., 1999; Bains et al., 2000, Prakash Babu et al., 2002).
Vertical barium profiles in the ocean resemble profiles of silicic acid and alkalinity, suggesting
that biological processes strongly influence the barium distribution throughout the ocean (Lea &
Boyle, 1989, Jeandel et al., 1996; De La Rocha, 2006). Although the marine budget of barium is
only approximately known, it does appear to be both balanced and controlled by biogenic particle
formation (De La Rocha, 2006). Since biogenic barite will not dissolve in seawater and diagenetic
mobility can be excluded in this interval of the sedimentary section (Arndt et al., 2006), it may
serve as a direct control for productivity. Based on this assumption a decline in productivity starting
in the pre-PETM interval is indicated.
A first minimum is reached preceding the CIE, while Ca/Al ratio and carbonate content is
55
CHAPTER III
still high. In the samples below the clay layer values rise before they drop concomitant to the CIE
onset to their lowest values. The decline in productivity recovers quickly to pre-event values within
the peak phase interval, during the time while the release of carbon to the ocean-atmosphere system
led to a rapid lowering of the deep-sea pH and a shoaling of the carbonate compensation depth
(Zachos et al., 2005).
Si/Al ratios in the peak phase are lower than average shale, reflecting intense weathering in
the source of the terrigenous detritus. Based on the Si/Al profile alone one cannot decide, whether
the decline is due to a change in productivity or a change in sedimentation rate. The burial of
biogenic silica depends on the rain rate of sedimented material (Broecker & Peng, 1982), and
therefore the decline in carbonate either due to dissolution or lower productivity will impact the
accumulation of bio-silica.
The formation of barite is associated with siliceous phytoplankton (Bishop, 1988), especially
Acantharian skeletons (Bernstein & Byrne, 1998). There is abundant evidence for a strong
relationship between barite and export productivity in the modern ocean (Bains et al., 2000).
Solid-phase Ba preservation may be compromised in some geochemical settings (McManus et al.,
1998). Under suboxic (=dysoxic) diagenetic conditions, characterised by the absence of detectable
pore water oxygen and sulphide, low bottom water oxygen and high organic carbon respiration
rates, Ba preservation may be reduced (McManus et al., 1998), Ba-remobilisation, however, takes
place in deeper parts of the sediment column (Arndt et al., 2009). Even though the shape of the
Mg/Al profile (Fig. 3.6d) exhibits some similarities to Ca and Sr, there seems to be no significant
incorporation of this element into the carbonate phase. By contrast, it correlates very well with
the Al content (r2=0.988; not shown here). The shift in Mg/Al at the onset of the peak phase
therefore might be due to the provenance change mentioned in the previous chapter. The redoxsensitive Mn/Al record indicates suboxic environment during the peak phase and the Ba/Al record
shows its lowest results at the onset of the CIE. However, the Ba/Al record drops clearly in the
pre-PETM interval and recovers quickly during the peak-phase, suggesting major perturbation
in marine bioproductivity. For calcareous nannofossil studies from Demerara Rise Jiang & Wise
(2006) and Mutterlose et al. (2007) report barren samples overlain by nearly barren samples during
the PETM onset, because of the risen CCD. On the other hand calcareous nannofossil Sr/Ca
records, across the PETM (Site 1258A) suggest neutral to slightly decreased productivity during
the PETM (Stoll et al., 2007). Deep photic calcareous nannofossil taxa experienced productivity
stimulation consistent with greater ocean stratification and possibly heat stress in the upper photic
zone in tropical areas (Stoll et al., 2007).
Phosphorus, included in organic matter, is sedimented as particulate organic matter (POM)
in marine environments (Filippelli & Delaney, 1996; Schenau et al., 2005). The implications of the
P/Al records towards productivity during the PETM show minor differences to the Ba/Al record.
The P/Al record shows descending burial of nutrients, preceding the PETM onset, following a
maximum in the late pre-PETM interval. In contrast to the Ba record the descent starts later in the
56
DISCUSSION
P record. The rate of P accumulation is driven by river and atmospheric input, linked to the rates
of continental weathering, erosion and runoff, as well as the degree of bottom-water oxygenation
(Bodin et al., 2006). A decrease in P accumulation rates indicates either a decrease in continental
weathering rates, or a spread of dysaerobic to anoxic bottom-waters, or the combination of both
processes (Bodin et al., 2006). In this case the latter might be the reason.
A number of trace elements, particularly first row transition metals (Mn, Fe, Ni, Co,
Cu, Zn and Cd) are essential for the growth of organisms, and therefore iron and manganese are
quantitatively the most important trace elements in marine phytoplankton, being on average about
10 times more abundant than zinc, copper, cobalt or cadmium (Morel et al., 2006). The major
algal nutrients are carbon, nitrogen, phosphorus and silicon. Zinc and iron do not change during
the investigated interval. Mn shows decreasing concentrations during the peak phase. Co and Ni
records show rising values in the peak phase, suggesting good conditions for phytoplankton growth.
Some elements (Ag, Cd, Cu, Ni and Zn) are concentrated by higher plankton productivity or
bioconcentration (Turgeon & Brumsack, 2006), transported to the sediment and released during
decomposition (Boyle et al., 1976; Bruland, 1980, 1983; Martin et al., 1983). However, abundances
of copper, zinc and nickel do not exhibit a consistent pattern in the PETM interval.
Iron plays a key role as a nutrient, since many marine ecosystems are iron-limited.
Phytoplankton growth and photosynthesis are frequently limited by the lack of iron in surface
waters (Martin & Fitzwater, 1989). The atmospheric transport of continental weathering products
is responsible for most of the minerals and Fe entering the open ocean and probably the dominant
source of nutrient Fe in the photic zone (Duce & Tindale, 1991). Fe is mostly introduced into the
ocean in form of airborne particles of goethite and limonite transported by winds from arid seas
(Sahara, Gobi) (Albarède, 2009). Atmospheric transport from the continents is estimated to supply
~3 times as much dissolved Fe to the oceans as that delivered via rivers (Duce & Tindale, 1991).
Fe is also transported in rivers (data from the Amazon River) as crystal (45.5%) metallic coatings
(47.2%), organic (6.5%) and in solution (0.8%) (Gibbs, 1973). Fe/Al values do not show changes
in the investigated interval. However, total Fe2O3 and Al2O3 increase with the onset of the PETM
as a result of the lacking calcium carbonate dilution. At the Paleocene-Eocene boundary, a strong
reduction in wind intensity occurred (Rea, 1994). Before then, latest Cretaceous and Paleocene
winds were essentially as strong as those of the late Cenozoic. This shift appears to be one of several
climatic responses to a change in the global heat transport at about 55Ma (Rea, 1994). Eolian
grain size decreases rapidly to the very low values that characterize the Eocene and document a
significant decrease in the intensity of atmospheric circulation at the P-E boundary (Janecek &
Rea, 1983). The early Eocene was characterised by the warmest climate of the Cenozoic, there were
greater concentrations of dissolved organic carbon in the ocean, and atmospheric and sea surface
circulation was sluggish (Rea, 1994). Latest models suggest altered ocean circulation patterns (Lunt
et al., 2011) and declining equatorial upwelling (Winguth et al., 2012) for the early stage of the
PETM.
57
CHAPTER III
3.4.5. Redox-sensitive elements
Co, Ni, Cu, Mn, Cr, Zn, V and Pb (Fig. 3.4) are redox-sensitive trace elements. Ratios of Ni/Al
increase within the peak phase interval and subsequently drop rapidly to pre-event values. The flux
of Ni to the sediment may be increased by complexing and sedimentation with organic matter,
and re-mineralization of the latter at or below the sediment-water interface may liberate Ni to
sediment pore waters (Algeo & Maynard, 2004). Co/Al values show the same pattern, except higher
abundances within the peak phase interval. Cobalt forms an insoluble sulfide in anoxic (depleted in
oxygen that virtually all aerobic biological activity has ceased (Demaison & Moore, 1980) waters,
which can be taken up by authigenic Fe-sulfides (Huerta-Diaz & Morse, 1992).
The ratios of V/Al and Mn/Al show a sudden decrease concomitant to the CIE. Where
oxygen penetrates 1 cm or less into the sediments, Mo and V diffuse to the overlying water as Mn
is reduced and remobilized (Morford & Emerson, 1999). However, V shows strong similarities
to the patterns of detritus-sensitive elements K and Rb. Subtle changes in the V concentration of
sediments could have a pronounced effect on its seawater concentration and could be significant
with respect to its river flux (Morford & Emerson, 1999). Furthermore V shows high correlations to
Al (p<0.001; r2 = 0.88; not shown here) implicating a detrital origin. Manganese that is involved in
the geochemical cycle in the ocean is supplied to the ocean as oxide coatings on particulate material
delivered by wind or by rivers and by diffusion from shelf sediments (Calvert & Pedersen, 1993).
Dickens & Owen (1994) suggest that Mn depletions reflect diminished deposition of reducible
Mn oxyhydroxide phases within O2 deficient intermediate waters. Facing reducing conditions,
Mn2+ diffuses from the sediment/water interface into oxygen-depleted bottom waters (Landing &
Bruland, 1980; Bruland, 1983; Landing & Bruland, 1987). In contrast to the depletion of Mn,
other typically redox-sensitive elements (e.g., Cu, Cr, Co, Ni, Zn) or element/Al ratios show no
major change across the PETM. Uranium and Mo are below the detection threshold. These data
suggest, that paleoenvironmental conditions were probably not oxygen-limited in our study site.
Evidence from trace fossil abundances at eastern Marlborough, New Zealand suggest
that South Pacific intermediate waters became hypoxic coincident to the CIE (Nicolo et al.,
2010). The increase rate of terrigenous input and highest fossil abundance in the later stage of
the PETM, probably reflects higher global temperatures because of an accelerated hydrological
cycle (Nicolo et al., 2010). Lippert & Zachos (2007) report high concentration of single-domain
magnetite immediately above the (P-E) boundary as a result of unusual accumulations and/or
preservation of magnetotactic bacteria, which typically occupy the oxic-anoxic transition zone near
the sediment-water interface or in the water column. One explanation is a shift of the oxic-anoxic
redox boundary into the water column, implying transient eutrophy of the coastal ocean, due to
seasonally enhanced runoff, and increased stratification and nutrient loading (Lippert & Zachos,
2007). Results from the Walvis Ridge indicate that oxygen concentrations did drop during the
PETM, but not sufficiently to cause massive extinction of benthic foraminifera (Chun et al., 2010).
Mn enrichment factors at Walvis Ridge (Chun et al., 2010) show a similar drop of values during the
58
CONCLUSION
CIE, compared to our Demerara Rise record. During the recovery, however, Mn enrichment factors
at Walvis Ridge are slightly higher compared to the pre-event (Chun et al., 2010). In contrast the
Mn/Al ratio at Demerara Rise stays below the pre-event values. In the Dababiya section, Egypt
the base of the PETM beds corresponds to the onset of sediment lamination indicative of oxygendeficiency at the seafloor (Schulte et al., 2011). Eutrophic conditions or enhanced productivity for
the PETM have been reported from several locations (i.e. Kaiho et al., 1996; Speijer et al., 1996;
Bujak & Brinkhuis, 1998; Crouch et al., 2001; Gibbs et al., 2006; Zachos et al., 2006). Compared
to oceanic anoxic events (OAEs), the PETM shares several features: Similar possible triggering
mechanisms, which are able to supply isotopical light carbon, like the venting of volcanogenic
carbon dioxide, dissociation of gas hydrates and/or thermal metamorphism of coals (Jenkyns, 2003;
McElwain et al., 2005; Kuroda et al., 2007). The decline in carbonate saturation is less pronounced
compared to future scenarios and the surface-ocean carbonate saturation (Ω) declines around
an order of magnitude slower than in future scenarios (Ridgwell & Schmidt, 2010). The carbon
isotope signature of the PETM dominantly records only the injection of isotopically light carbon
into the ocean-atmosphere system (Jenkyns, 2010). Paleogeography was not, except in the case of
the Arctic Ocean (Sluijs et al., 2008), conductive to water column stratification and development
of extensive euxinic conditions (Jenkyns, 2010). Data from OAE 2 at Demerara Rise 1258 (Hetzel
et al., 2009) show similar trends, compared with our results: Co/Al values within the events point
to euxinic conditions. Low Mn/Al ratios in both cases proof the existence of an expansion of the
oxygen minimum zone (OMZ).
3.5. Conclusion
Our geochemical record of the PETM from the deep-sea Site 1258C (Demerara Rise) led to the
following conclusions:
• The peak phase is dominated by terrigenous input. K/Al ratios suggest a change in
provenance or more intense weathering in the hinterland.
• Three ash layers are present during the recovery phase of the PETM indicating high
volcanic activity in the region.
• During the peak phase carbonate as well as bio-silica completely declines, indicating a short-termed breakdown of the planktic community.
• The decline of productivity sensitive elements starts slightly before the CIE.
• The Ba productivity record shows a massive breakdown in productivity during the onset of the PETM.
• Titanium and zirconium show higher abundances during the peak phase, which suggests higher input of siliciclastic detritus and perhaps enhanced bottom currents.
• Redox sensitive element/Al ratios suggest paleoenvironmental conditions were probably not oxygen-limited.
59
CHAPTER III
The authors like to thank the Bundesministerium für Bildung und Forschung for the financial
support of this project, included in the BIOACID joint research programme. Dr. Nils Andersen
(CAU, Kiel) is thanked for measuring the δ13Cbulk and δ18Obulk of all samples with a carbonate
content <20%.
Pre-PETM
Peak phase
Body
Recovery
Terrigenous
27
92
79
48
Carbonate
48
1
10
29
Excess silica
24
4
10
22
Barite
0.1
0.2
0.2
0.1
Pyrite
0.7
2.5
1.7
1.0
Fig. 3.8: Major components of the different PETM stages recovered from ODP Site 1258C (ODP leg 207,
Demerara Rise).
60
APPENDIX
mean
values
!C
!S
SiO2
TiO2
Al2O3
Fe2O3
MnO
MgO
CaO
Na2O
K2 O
P2O5
Ba
Co
Cr
Cu
Ni
Rb
Sr
V
Y
Zn
Zr
Si/Al
Ti/Al
Fe/Al
Mn/Al
Mg/Al
Ca/Al
Na/Al
K/Al
P/Al
Ba/Al
Co/Al
Cr/Al
Cu/Al
Ni/Al
Rb/Al
Sr/Al
V/Al
Y/Al
Zn/Al
Zr/Al
peak
body
phase
5.44
0.11
1.15
0.34
1.19
0.83
37.81
54.87
52.26
0.196
0.701
0.488
5.29
18.17
15.32
1.32 (1.83) 5.23 (5.58) 4.92 (5.20)
0.0628
0.0195
0.0318
0.68
1.78
1.47
25.9
0.69
5.06
1.09
1.79
1.84
0.88
1.468
1.66
0.064
0.130
0.111
877
2677
2704
3.6
19.5
17.7
30 (36)
76
69
21 (59)
70
33
16
90
62
29
61
67
619
259
378
51
111
107
13.6
26.8
21.5
43 (162)
79
73
46
146
94
6.52
2.672
3.06
0.042
0.044
0.036
0.35 (0.43) 0.38 (0.41) 0.42 (0.45)
0.0179
0.0016
0.0033
0.15
0.11
0.11
6.85
0.052
0.51
0.29
0.14
0.17
0.26
0.13
0.17
0.0101
0.0059
0.0059
323
280
334
1.3
2.0
2.1
10.9 (12.5)
7.9
8.6
7.4 (21.1)
7.2
4.0
5.7
9.4
7.4
10.4
6.4
8.3
225
27
49
18.2
11.6
13.3
4.9
2.8
2.7
16.7 (57)
8.2
9.0
16.5
15.15
11.4 (11.8)
pre-PETM
recovery
phase
3.28
0.54
46.69
0.325
9.52
2.47 (2.84)
0.0523
0.99
15.2
1.69
1.53
0.070
1591
6.3
48
20 (37)
20
48
560
90
15.2
48 (50)
64
4.37
0.039
0.34 (0.40)
0.0082
0.12
2.21
0.25
0.25
0.0061
317
1.3
9.4 (9.6)
3.8 (7.8)
3.9
9.5
113
17.8
3.0
9.5 (9.9)
12.8
PETM data listed exclude extreme values (in brackets values including extremes)
*average shale values from Wedepohl, 1971 and 1991
average
shale*
0.35
0.2
58.9
0.78
16.7
6.90
0.11
2.6
2.2
1.6
3.6
0.16
580
19
90
45
68
140
300
130
41
95
160
3.11
0.053
0.55
0.0096
0.18
0.18
0.13
0.34
0.008
66
2.1
10.2
5.1
7.7
16
34
15
4.6
11
18
Fig. 3.9: Major and minor element concentrations and Al-ratios of the different PETM stages recovered
from ODP Site 1258C (ODP leg 207, Demerara Rise) in comparison to average shale of Wedepohl (1971)
and Wedepohl (1991).
61
CHAPTER III
Depth (mbsf)
194.27
194.29
194.31
194.33
194.35
194.37
194.40
194.47
194.53
194.56
194.57
194.60
194.63
194.67
194.69
194.75
194.78
194.82
194.85
194.90
194.94
194.96
195.00
195.04
195.06
195.10
195.14
195.16
195.20
195.24
195.26
195.30
195.32
195.34
195.35
195.36
195.38
195.40
195.41
195.45
195.47
195.49
195.50
195.51
195.53
195.55
195.57
195.59
195.60
195.61
195.63
195.65
195.67
195.70
195.73
195.75
195.77
195.79
195.80
195.81
195.83
195.85
195.87
195.89
195.90
195.93
195.94
195.95
195.97
196.00
∑C
∑S
SiO2
TiO2
Al2O3 Fe2O3
MnO
MgO CaO Na2O K2O P2O5
4.2668
4.0855
4.1753
4.0978
3.9091
3.3836
3.5969
3.122
2.4787
2.80
2.67
0.847
2.203
0.246
0.403
0.104
0.155
0.24
0.552
0.432
0.25
0.50
2.96
3.22
3.06
3.65
3.84
3.40
3.12
2.88
3.10
3.24
3.23
3.62
3.09
2.63
2.92
2.88
2.63
2.17
2.10
2.07
2.53
1.65
1.68
1.60
1.01
0.96
0.74
0.09
0.04
0.18
0.17
0.06
0.09
0.26
5.97
0.09
0.10
0.11
0.16
0.30
0.31
0.43
0.38
0.40
0.57
0.84
0.72
0.68
0.58
0.47
0.51
0.61
0.91
0.77
0.35
0.19
0.10
0.08
0.07
0.08
0.12
0.07
0.08
0.07
0.06
0.34
0.07
0.17
0.14
0.10
4.42
5.37
5.17
5.4507
6.4689
6.4831
6.1506
5.5869
4.916
5.5723
5.2428
5.1018
5.0382
5.2769
1.49
2.55
0.59
0.45
0.73
0.74
4.03
0.89
0.99
0.79
1.06
0.91
0.93
1.13
0.70
0.91
2.46
0.66
0.81
0.151
0.19
0.014
0.017
0.011
0.067
0.142
0.133
0.017
0.011
0.066
41.32
40.83
42.25
42.49
43.59
46.15
45.06
46.24
49.20
49.66
49.29
49.24
49.48
47.96
49.17
45.14
45.88
46.41
47.61
43.32
48.82
48.56
47.54
47.02
47.54
50.15
48.14
47.73
48.11
48.74
50.05
50.21
45.85
50.27
50.81
50.77
52.30
52.48
51.66
55.35
54.90
53.52
56.59
56.27
56.44
56.83
52.57
55.65
55.38
56.21
54.91
54.01
54.18
54.07
54.83
54.96
35.54
34.80
36.70
35.77
30.44
32.34
34.67
39.57
44.32
38.93
40.22
42.53
42.56
40.96
0.284
0.293
0.300
0.308
0.322
0.364
0.338
0.382
0.418
0.372
0.362
0.338
0.314
0.304
0.301
0.285
0.269
0.305
0.336
0.326
0.309
0.289
0.301
0.279
0.316
0.344
0.347
0.353
0.362
0.393
0.397
0.405
0.376
0.472
0.454
0.454
0.497
0.502
0.549
0.540
0.538
0.535
0.569
0.556
0.574
0.576
0.579
0.738
0.724
0.614
0.723
0.707
0.787
0.795
0.667
0.806
0.249
0.229
0.228
0.268
0.178
0.158
0.169
0.164
0.164
0.183
0.197
0.181
0.186
0.183
8.05
8.33
8.53
8.72
9.09
10.25
9.61
10.88
12.35
10.97
10.55
9.88
9.24
8.72
8.88
8.30
7.91
8.91
9.87
9.42
9.16
8.69
8.98
8.53
9.53
10.33
10.52
10.85
11.16
12.02
12.37
12.58
11.33
14.39
13.97
14.24
15.77
16.02
17.59
17.41
17.35
17.04
18.06
17.62
17.44
17.75
16.48
18.67
18.57
17.51
18.46
18.19
19.12
18.25
18.02
18.85
6.92
6.36
6.36
7.38
4.92
4.29
4.54
4.45
4.50
4.75
5.21
4.77
4.84
4.89
0.057
0.055
0.056
0.054
0.055
0.047
0.050
0.045
0.037
0.044
0.043
0.048
0.049
0.053
0.048
0.065
0.067
0.062
0.057
0.052
0.054
0.056
0.059
0.062
0.055
0.046
0.048
0.048
0.046
0.039
0.040
0.042
0.048
0.042
0.044
0.044
0.034
0.032
0.030
0.020
0.020
0.018
0.019
0.018
0.019
0.019
0.019
0.020
0.020
0.018
0.020
0.023
0.020
0.018
0.018
0.019
0.058
0.065
0.062
0.060
0.077
0.073
0.067
0.060
0.050
0.062
0.060
0.061
0.060
0.064
0.86
0.87
0.93
0.95
0.94
1.00
0.99
1.10
1.19
1.07
1.05
0.98
0.93
0.95
0.96
0.98
0.90
0.95
1.04
0.98
0.92
0.90
0.98
0.90
0.97
1.07
1.10
1.12
1.12
1.23
1.23
1.26
1.17
1.47
1.41
1.38
1.52
1.49
1.59
1.58
1.59
1.58
1.72
1.66
1.70
1.66
1.68
1.79
1.84
1.77
1.85
1.78
1.85
1.77
1.74
1.83
0.81
0.78
0.77
0.89
0.66
0.58
0.60
0.59
0.57
0.65
0.68
0.61
0.63
0.65
3.72
4.67
2.22
2.43
2.29
2.47
2.47
3.09
3.27
2.58
2.75
2.34
2.05
2.05
2.17
2.15
1.90
2.18
2.64
9.86
2.10
2.00
2.12
2.06
2.59
2.74
3.14
3.14
3.17
3.56
4.20
4.18
6.18
5.03
4.46
4.19
5.18
5.47
5.73
5.45
5.34
8.09
5.48
5.28
5.36
5.31
9.15
5.31
5.46
5.34
5.36
5.17
5.12
5.20
4.97
5.02
6.39
2.46
2.25
2.11
1.41
1.13
1.20
1.11
1.03
1.31
1.45
1.23
1.24
1.29
19.77
19.31
19.77
19.40
18.53
15.99
16.93
14.76
11.71
12.88
12.45
13.38
13.71
14.99
14.12
17.08
17.48
15.69
14.31
12.64
14.30
14.99
15.21
16.11
14.41
12.33
13.59
13.03
12.33
11.02
9.57
9.27
11.09
7.43
7.76
7.46
4.46
4.30
3.33
1.43
1.41
0.74
0.60
0.50
0.57
0.62
0.50
0.47
0.62
0.49
0.42
1.83
0.48
1.11
0.60
0.50
21.56
25.38
24.55
25.39
31.12
30.79
29.18
26.52
23.37
26.34
25.14
24.25
24.22
25.04
1.54
1.36
1.60
1.55
1.54
1.49
1.61
1.57
1.64
1.77
1.76
1.81
1.76
1.76
1.80
1.64
1.65
1.73
1.77
1.41
1.80
1.84
1.82
1.79
1.77
1.88
1.71
1.73
1.83
1.80
1.78
1.80
1.82
1.79
1.88
1.82
1.78
1.83
1.67
1.89
1.96
1.90
1.85
1.84
1.96
1.84
1.61
1.75
1.77
1.80
1.74
1.78
1.78
2.03
1.84
1.72
1.23
1.16
1.26
1.14
1.05
0.94
0.95
1.05
1.21
1.04
1.06
1.05
1.06
1.03
1.27
1.27
1.29
1.31
1.37
1.50
1.43
1.47
1.61
1.62
1.63
1.60
1.62
1.59
1.60
1.48
1.51
1.63
1.67
1.42
1.65
1.64
1.59
1.52
1.63
1.69
1.59
1.65
1.64
1.56
1.61
1.61
1.46
1.62
1.67
1.69
1.64
1.65
1.61
1.75
1.73
1.69
1.74
1.72
1.75
1.78
1.54
1.42
1.47
1.65
1.40
1.37
1.32
1.28
1.52
1.32
1.06
0.97
0.99
1.02
0.79
0.74
0.80
0.80
0.80
0.84
0.90
0.83
0.86
0.85
0.072
0.068
0.069
0.070
0.072
0.073
0.068
0.071
0.066
0.061
0.059
0.064
0.066
0.077
0.073
0.070
0.071
0.077
0.073
0.070
0.063
0.062
0.062
0.057
0.061
0.077
0.085
0.083
0.083
0.084
0.083
0.091
0.079
0.095
0.099
0.106
0.116
0.115
0.119
0.118
0.122
0.120
0.141
0.146
0.142
0.168
0.135
0.134
0.133
0.147
0.126
0.120
0.116
0.118
0.116
0.116
0.072
0.072
0.064
0.093
0.070
0.061
0.057
0.054
0.052
0.059
0.061
0.060
0.063
0.064
Ba
1281
1235
1249
1292
1231
1540
1451
1544
1608
1501
1591
1626
1440
1727
1770
1779
1507
1649
1684
1252
1641
1595
1626
1754
1781
2012
1907
1887
1979
2042
2205
2394
2209
2496
2461
2539
2650
2830
2908
2884
2978
2909
3276
3090
3399
2975
3388
3448
3618
3218
3252
2482
2019
1015
2031
1997
865
814
898
645
593
628
719
874
818
970
1086
1104
1104
1160
Co Cr
5
3
6
6
4
4
5
5
8
5
7
8
6
6
6
7
6
7
7
12
7
6
7
6
6
6
7
8
8
7
9
10
11
15
13
11
11
13
12
15
18
23
42
44
29
25
19
16
16
22
20
19
16
21
18
22
5
5
5
4
4
4
3
4
2
3
5
3
3
1
Cu
Ni Pb Rb
46 347 13 60 41
51 20 21 9 41
41 16 16 8 43
41 16 18 6 44
46 16 21 7 49
50 48 21 46 53
46 19 19 8 50
52 28 26 10 54
55 26 29 12 57
73 37 30 9 52
50 58 23 12 54
53 33 16 5 62
39 17 16 6 46
43 21 18 6 45
46 17 20 6 47
42 16 18 8 43
41 46 17 14 41
44 13 18 5 47
45 23 23 8 49
75 63 44 11 44
43 15 13 4 48
40 14 14 4 45
45 69 18 44 44
38 12 15 5 42
46 17 18 6 48
49 15 20 5 50
65 13 24 5 50
50 25 21 6 52
51 20 24 8 52
63 21 30 20 54
66 33 31 10 58
57 24 36 11 58
56 26 37 11 54
67 27 61 12 66
66 27 56 12 65
67 27 52 8 64
71 28 47 8 66
68 34 44 8 69
78 33 44 7 73
76 40 45 9 72
73 37 56 10 74
76 39 72 9 74
75 38 121 17 75
73 41 139 18 72
78 46 120 17 71
68 52 124 18 70
68 49 95 18 66
77 62 83 18 61
76 57 79 15 64
72 64 108 17 67
79 74 89 17 60
78 76 81 18 59
81 87 77 18 57
75 80 95 20 54
83 70 63 12 65
77 98 101 20 51
93 52 24 15 36
36 20 21 7 34
35 310 15 30 33
37 31 26 8 37
24 23 11 6 26
24 208 12 15 22
45 31 17 10 25
29 20 17 18 27
22 13 10 4 24
27 17 14 5 26
39 15 20 4 29
28 44 11 2 28
28 20 11 3 29
32 26 15 3 30
Fig.3.10a: Geochemistry results from the PETM 1258C (Demerara Rise).
62
Sr
V
Y
Zn
579
585
637
635
612
594
573
540
503
560
568
549
572
574
599
581
565
579
547
463
552
528
686
509
491
512
522
540
497
481
474
468
467
409
430
442
364
372
318
316
338
288
291
288
306
294
283
238
252
274
232
259
246
345
220
201
626
675
702
781
755
693
648
584
533
609
553
505
500
496
86
92
94
102
101
114
104
111
115
101
100
82
86
83
81
78
71
86
92
82
79
69
80
71
82
90
90
87
88
98
84
89
90
121
110
105
111
104
111
114
108
115
117
117
114
116
107
115
116
114
112
114
112
97
116
107
67
62
66
58
46
38
42
40
45
48
54
50
49
49
16
15
15
16
14
16
15
15
16
13
15
8
15
15
15
15
14
15
16
16
15
14
17
14
17
16
18
18
17
18
18
19
17
20
20
20
23
22
21
22
22
22
26
28
27
28
25
30
28
29
28
26
26
26
22
27
14
13
14
17
15
14
12
12
11
13
13
14
14
14
49
52
51
53
48
69
54
60
82
56
59
42
38
37
39
43
35
40
103
60
35
34
37
47
48
50
43
42
45
51
55
54
65
74
67
69
74
80
82
82
87
84
82
78
78
77
89
79
80
77
77
79
75
70
85
77
129
479
46
144
1086
28
24
21
20
24
48
63
82
77
Zr Mo
60
62
64
65
67
72
68
76
78
71
70
51
62
58
58
57
57
60
65
77
58
59
58
56
62
66
66
67
68
76
74
76
109
89
84
85
89
94
102
102
101
105
111
108
110
115
123
156
153
127
154
147
164
167
133
167
57
51
51
59
42
38
42
42
38
43
48
44
44
43
3
2
2
2
1
1
2
1
1
2
1
2
1
1
2
0
1
1
2
4
1
3
2
3
1
0
0
2
0
1
1
4
2
2
0
2
1
3
2
1
1
2
1
2
0
1
2
0
1
0
1
3
0
2
1
3
2
0
1
2
2
3
1
2
2
1
3
1
2
2
APPENDIX
Depth (mbsf)
194.27
194.29
194.31
194.33
194.35
194.37
194.40
194.47
194.53
194.56
194.57
194.60
194.63
194.67
194.69
194.75
194.78
194.82
194.85
194.90
194.94
194.96
195.00
195.04
195.06
195.10
195.14
195.16
195.20
195.24
195.26
195.30
195.32
195.34
195.35
195.36
195.38
195.40
195.41
195.45
195.47
195.49
195.50
195.51
195.53
195.55
195.57
195.59
195.60
195.61
195.63
195.65
195.67
195.70
195.73
195.75
195.77
195.79
195.80
195.81
195.83
195.85
195.87
195.89
195.90
195.93
195.94
195.95
195.97
196.00
U Ce Th
2
1
1
3
0
0
0
1
2
2
1
0
1
1
1
2
2
0
2
4
1
1
1
1
1
1
1
2
2
2
1
2
2
1
1
3
2
3
2
3
2
2
3
3
2
3
2
2
4
3
1
2
4
2
2
2
0
0
0
1
2
1
0
0
1
1
1
1
1
1
47
49
62
38
27
47
60
67
58
22
36
61
61
62
36
19
47
44
39
19
44
60
35
23
61
51
73
72
80
75
43
62
60
72
63
100
80
110
56
84
85
91
97
95
88
93
117
82
101
71
86
51
63
63
78
27
25
63
38
64
34
18
35
16
19
33
3
4
40
27
Al
12 4.26
12 4.41
16 4.52
15 4.62
7 4.81
5 5.43
6 5.09
12 5.76
13 6.54
10 5.81
9 5.58
7 5.23
13 4.89
9 4.62
5 4.70
8 4.39
7 4.19
16 4.72
10 5.22
7 4.99
9 4.85
7 4.60
8 4.75
8 4.52
8 5.04
12 5.47
14 5.57
12 5.74
17 5.91
15 6.36
12 6.55
10 6.66
12 6.00
12 7.62
12 7.40
15 7.54
12 8.35
19 8.48
16 9.31
18 9.22
15 9.18
16 9.02
20 9.56
19 9.33
15 9.23
25 9.40
20 8.72
18 9.88
20 9.83
19 9.27
14 9.77
13 9.63
23 10.12
17 9.66
19 9.54
11 9.98
12 3.66
9 3.37
8 3.37
7 3.91
7 2.60
9 2.27
3 2.40
3 2.36
7 2.38
11 2.51
6 2.76
5 2.53
8 2.56
4 2.59
Si/Al
Ti/Al
Fe/Al
4.533
4.329
4.374
4.303
4.235
3.976
4.141
3.753
3.518
4.00
4.13
4.40
4.73
4.86
4.89
4.80
5.12
4.60
4.26
4.06
4.71
4.93
4.68
4.87
4.41
4.29
4.04
3.88
3.81
3.58
3.57
3.52
3.57
3.09
3.21
3.15
2.93
2.89
2.59
2.81
2.79
2.77
2.77
2.82
2.86
2.83
2.82
2.63
2.63
2.83
2.63
2.62
2.50
2.62
2.69
2.57
4.54
4.83
5.10
4.28
5.464
6.657
6.744
7.853
8.698
7.238
6.817
7.874
7.765
7.397
0.040
0.040
0.040
0.040
0.040
0.040
0.040
0.040
0.038
0.038
0.039
0.039
0.038
0.039
0.038
0.039
0.039
0.039
0.039
0.039
0.038
0.038
0.038
0.037
0.038
0.038
0.037
0.037
0.037
0.037
0.036
0.036
0.038
0.037
0.037
0.036
0.036
0.035
0.035
0.035
0.035
0.036
0.036
0.036
0.037
0.037
0.040
0.045
0.044
0.040
0.044
0.044
0.047
0.049
0.042
0.048
0.041
0.041
0.041
0.041
0.041
0.042
0.042
0.042
0.041
0.044
0.043
0.043
0.044
0.042
0.610
0.741
0.344
0.368
0.333
0.318
0.340
0.375
0.350
0.311
0.344
0.313
0.293
0.311
0.323
0.342
0.317
0.323
0.353
1.383
0.303
0.304
0.312
0.319
0.359
0.350
0.394
0.382
0.375
0.391
0.449
0.439
0.721
0.462
0.422
0.389
0.434
0.451
0.430
0.414
0.407
0.627
0.401
0.396
0.406
0.395
0.733
0.376
0.388
0.403
0.384
0.375
0.354
0.376
0.364
0.352
1.220
0.511
0.467
0.378
0.379
0.348
0.349
0.330
0.302
0.364
0.368
0.341
0.338
0.348
Mn/Al Mg/Al Ca/Al Na/Al K/Al
0.01036
0.00966
0.00961
0.00906
0.00885
0.00671
0.00761
0.00605
0.00438
0.0059
0.0060
0.0071
0.0078
0.0089
0.0079
0.0115
0.0124
0.0102
0.0085
0.0081
0.0086
0.0094
0.0096
0.0106
0.0084
0.0065
0.0067
0.0065
0.0060
0.0047
0.0047
0.0049
0.0062
0.0043
0.0046
0.0045
0.0032
0.0029
0.0025
0.0017
0.0017
0.0015
0.0015
0.0015
0.0016
0.0016
0.0017
0.0016
0.0016
0.0015
0.0016
0.0019
0.0015
0.0014
0.0015
0.0015
0.0123
0.0150
0.0143
0.0119
0.0229
0.0249
0.02159
0.01973
0.01626
0.0191
0.01685
0.01871
0.01814
0.01915
0.122
0.119
0.124
0.124
0.118
0.111
0.117
0.115
0.110
0.111
0.113
0.113
0.115
0.124
0.123
0.135
0.130
0.121
0.120
0.118
0.114
0.118
0.124
0.120
0.116
0.118
0.119
0.118
0.114
0.117
0.113
0.114
0.118
0.116
0.115
0.110
0.110
0.106
0.103
0.103
0.104
0.106
0.109
0.107
0.111
0.107
0.116
0.109
0.113
0.115
0.114
0.111
0.110
0.110
0.110
0.111
0.133
0.140
0.138
0.137
0.153
0.154
0.151
0.151
0.144
0.156
0.149
0.146
0.148
0.151
3.32
3.13
3.13
3.00
2.75
2.11
2.38
1.83
1.28
1.59
1.59
1.83
2.00
2.32
2.15
2.78
2.98
2.38
1.96
1.81
2.11
2.33
2.29
2.55
2.04
1.61
1.74
1.62
1.49
1.24
1.04
1.00
1.32
0.70
0.75
0.71
0.38
0.36
0.26
0.11
0.11
0.06
0.04
0.04
0.04
0.05
0.04
0.03
0.05
0.04
0.03
0.14
0.03
0.08
0.04
0.04
4.21
5.39
5.21
4.65
8.54
9.69
8.68
8.05
7.01
7.49
6.52
6.86
6.76
6.91
0.27
0.23
0.26
0.25
0.24
0.20
0.23
0.20
0.19
0.23
0.23
0.26
0.27
0.28
0.28
0.28
0.29
0.27
0.25
0.21
0.28
0.30
0.28
0.29
0.26
0.26
0.23
0.22
0.23
0.21
0.20
0.20
0.23
0.17
0.19
0.18
0.16
0.16
0.13
0.15
0.16
0.16
0.14
0.15
0.16
0.15
0.14
0.13
0.13
0.14
0.13
0.14
0.13
0.16
0.14
0.13
0.25
0.26
0.28
0.22
0.30
0.31
0.29
0.33
0.38
0.31
0.29
0.31
0.31
0.30
0.25
0.24
0.24
0.24
0.24
0.23
0.23
0.21
0.20
0.23
0.24
0.25
0.27
0.29
0.28
0.28
0.30
0.29
0.27
0.24
0.28
0.30
0.28
0.28
0.27
0.26
0.24
0.24
0.23
0.20
0.20
0.20
0.20
0.18
0.19
0.19
0.16
0.16
0.14
0.16
0.16
0.16
0.15
0.15
0.16
0.16
0.15
0.12
0.12
0.15
0.12
0.12
0.11
0.11
0.13
0.11
0.24
0.24
0.24
0.22
0.25
0.27
0.28
0.28
0.28
0.28
0.27
0.27
0.28
0.27
P/Al Ba/Al Co/Al Cr/Al Cu/Al Ni/Al Pb/Al Rb/Al Sr/Al V/Al Y/Al Zn/Al Zr/Al
0.007
0.007
0.007
0.007
0.007
0.006
0.006
0.005
0.004
0.005
0.005
0.005
0.006
0.007
0.007
0.007
0.007
0.007
0.006
0.006
0.006
0.006
0.006
0.006
0.005
0.006
0.007
0.006
0.006
0.006
0.006
0.006
0.006
0.005
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.007
0.007
0.008
0.007
0.006
0.006
0.007
0.006
0.005
0.005
0.005
0.005
0.005
0.009
0.009
0.008
0.010
0.012
0.012
0.010
0.010
0.010
0.010
0.010
0.010
0.011
0.011
301
280
277
280
256
284
285
268
246
258
285
311
294
374
376
405
360
350
322
251
338
347
342
388
353
368
342
329
335
321
337
359
368
328
333
337
317
334
312
313
324
322
343
331
368
317
388
349
368
347
333
258
199
105
213
200
236
242
267
165
228
277
299
371
343
386
394
437
431
448
1.17
0.68
1.33
1.30
0.83
0.74
0.98
0.87
1.22
0.86
1.25
1.59
1.23
1.30
1.17
1.59
1.43
1.48
1.34
2.47
1.44
1.30
1.47
1.33
1.19
1.10
1.26
1.39
1.35
1.10
1.37
1.50
1.75
1.97
1.76
1.46
1.32
1.53
1.29
1.63
1.96
2.55
4.39
4.72
3.14
2.66
2.18
1.62
1.63
2.37
2.05
1.97
1.58
2.17
1.89
2.20
1.36
1.49
1.49
1.02
1.54
1.76
1.25
1.70
0.84
1.19
1.81
1.19
1.17
0.39
10.8
11.6
9.1
8.9
9.6
9.2
9.0
9.0
8.4
12.6
9.0
10.1
8.0
9.3
9.7
9.6
9.8
9.3
8.6
15.0
8.9
8.7
9.5
8.4
9.1
9.0
11.7
8.7
8.6
9.9
10.1
8.6
9.3
8.8
8.9
8.9
8.5
8.0
8.4
8.2
7.9
8.4
7.8
7.8
8.4
7.2
7.8
7.8
7.7
7.8
8.1
8.1
8.0
7.8
8.7
7.7
25.4
10.7
10.4
9.5
9.2
10.6
18.7
12.3
9.2
10.7
14.1
11.1
10.9
12.4
81.4
4.5
3.5
3.5
3.3
8.8
3.7
4.9
4.0
6.4
10.4
6.4
3.5
4.5
3.5
3.6
11.0
2.8
4.4
12.7
3.1
3.0
14.5
2.7
3.4
2.7
2.3
4.4
3.4
3.3
5.0
3.6
4.3
3.5
3.7
3.6
3.4
4.0
3.5
4.3
4.0
4.3
4.0
4.4
5.0
5.5
5.6
6.3
5.8
6.9
7.6
7.9
8.6
8.3
7.3
9.8
14.2
5.9
92.1
7.9
8.8
91.6
12.9
8.5
5.5
6.8
5.4
17.4
7.8
10.0
3.1
4.8
3.5
3.9
4.4
3.9
3.7
4.5
4.4
5.2
4.1
3.1
3.3
3.9
4.3
4.1
4.1
3.8
4.4
8.8
2.7
3.0
3.8
3.3
3.6
3.7
4.3
3.7
4.1
4.7
4.7
5.4
6.2
8.0
7.6
6.9
5.6
5.2
4.7
4.9
6.1
8.0
12.7
14.9
13.0
13.2
10.9
8.4
8.0
11.7
9.1
8.4
7.6
9.8
6.6
10.1
6.6
6.2
4.5
6.7
4.2
5.3
7.1
7.2
4.2
5.6
7.3
4.4
4.3
5.8
14.08
2.041
1.772
1.3
1.455
8.477
1.573
1.736
1.835
2
2.1
0.9
1.2
1.3
1.3
1.8
3.3
1.1
1.5
2.1
0.8
0.9
9.3
1.1
1.2
0.9
0.9
1.0
1.4
3.1
1.5
1.7
1.8
1.6
1.6
1.1
1.0
0.9
0.8
1.0
1.1
1.0
1.8
1.9
1.8
1.9
2.1
1.8
1.5
1.8
1.7
1.9
1.8
2.1
1.3
2.0
4.1
2.1
8.9
2.048
2.304
6.605
4.161
7.641
1.679
1.988
1.45
0.792
1.171
1.159
9.6
9.3
9.5
9.5
10.2
9.8
9.8
9.4
8.7
9.0
9.7
11.8
9.4
9.7
9.9
9.8
9.8
10.0
9.4
8.8
9.9
9.8
9.3
9.3
9.5
9.1
9.0
9.1
8.8
8.5
8.9
8.7
8.9
8.7
8.8
8.5
7.9
8.1
7.8
7.8
8.1
8.2
7.8
7.7
7.7
7.4
7.6
6.2
6.5
7.2
6.1
6.1
5.6
5.6
6.8
5.1
9.8
10.1
9.8
9.5
10.0
9.7
10.4
11.5
10.1
10.3
10.5
11.1
11.3
11.6
136
133
141
138
127
109
113
94
77
96
102
105
117
124
127
132
135
123
105
93
114
115
144
113
97
94
94
94
84
76
72
70
78
54
58
59
44
44
34
34
37
32
30
31
33
31
32
24
26
30
24
27
24
36
23
20
171
200
209
200
290
305
270
248
224
242
201
200
195
192
20.2
20.9
20.8
22.1
21.0
21.0
20.4
19.3
17.6
17.4
17.9
15.7
17.6
18.0
17.1
17.8
17.0
18.2
17.6
16.5
16.3
15.0
16.8
15.7
16.3
16.5
16.2
15.1
14.9
15.4
12.8
13.4
15.0
15.9
14.9
13.9
13.3
12.3
11.9
12.4
11.8
12.7
12.2
12.5
12.3
12.3
12.3
11.6
11.8
12.3
11.5
11.8
11.1
10.0
12.2
10.7
18.3
18.4
19.6
14.8
17.7
16.7
17.5
17.0
18.9
19.1
19.6
19.8
19.1
18.9
3.8 11.5 14.1
3.4 11.8 14.1
3.3 11.3 14.2
3.5 11.5 14.1
2.9 10.0 13.9
2.9 12.7 13.3
2.9 10.6 13.4
2.6 10.4 13.2
2.4 12.5 11.9
2
9.6 12.2
2.7 10.6 12.5
1.6
8.0
9.8
3.1
7.8 12.7
3.2
8.0 12.6
3.1
8.2 12.3
3.4
9.8 13.0
3.3
8.4 13.6
3.2
8.5 12.7
3.1 19.7 12.4
3.3 12.0 15.5
3.1
7.2 12.0
3.0
7.4 12.8
3.6
7.8 12.2
3.1 10.4 12.4
3.4
9.5 12.3
2.9
9.1 12.1
3.2
7.7 11.9
3.1
7.3 11.7
2.9
7.6 11.5
2.8
8.0 11.9
2.7
8.4 11.3
2.9
8.1 11.4
2.8 10.8 18.2
2.6
9.7 11.7
2.7
9.1 11.4
2.7
9.2 11.3
2.8
8.9 10.7
2.6
9.4 11.1
2.3
8.8 11.0
2.4
8.9 11.1
2.4
9.5 11.0
2.4
9.3 11.6
2.7
8.6 11.6
2.9
8.4 11.6
2.9
8.4 11.9
3.0
8.2 12.2
2.9 10.2 14.1
3.0
8.0 15.8
2.8
8.1 15.6
3.1
8.3 13.7
2.9
7.9 15.8
2.7
8.2 15.3
2.6
7.4 16.2
2.7
7.2 17.3
2.3
8.9 13.9
2.7
7.7 16.7
3.8 35.2 15.6
3.9 142.3 15.1
4.2 13.7 15.1
4.4 36.9 15.1
5.8 417.0 16.1
6.2 12.3 16.7
5
10.0 17.5
5.1
8.9 17.8
4.6
8.4 16.0
5.2
9.5 17.1
4.7 17.4 17.4
5.5 24.9 17.4
5.5 32.0 17.2
5.4 29.7 16.6
Fig.3.10b: Geochemistry results from the PETM 1258C (Demerara Rise).
63
CHAPTER IV
Chapter IV
Temperature related size variation in calcareous
nannofossils during the late Paleocene and early
Eocene
64
INTRODUCTION
Chapter IV: Temperature related size variation in calcareous nannofossils during
the late Paleocene and early Eocene
Christian Joachim a, *, Jörg Mutterlose a, Peter Schulteb & Christian Linnertc
Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Germany
a
GeoZentrum Nordbayern, Universität Erlangen, D-91054 Erlangen, Germany
b
c
University College London, Department of Earth Sciences, Gower Street, London WC1E 6BT, United Kingdom
* Corresponding author.
E-mail address: [email protected] (C. Joachim)
(This manuscript has been submitted to Marine Micropaleontology)
Abstract
The composition of calcareous nannofossil assemblages throughout the late Paleocene and early
Eocene has been investigated from 133 samples at an equatorial Atlantic Site (Demerara Rise;
ODP Sites 1260A & 1260B). The investigated intervals include the Paleocene - Eocene thermal
maximum (PETM), the Eocene thermal maximum 2 (ETM2) and Eocene thermal maximum 3
(ETM3). The three hyperthermal events (PETM, ETM2, ETM3) were marked by a substantial
input of isotopically light carbon into the oceans, superimposed on a general warming trend.
Compared to the PETM only minor changes in the nannofossil assemblages occur during the
ETM2 and ETM3, all three hyperthermal events are characterised by warm oligotrophic conditions.
Within the nannofossil species Coccolithus pelagicus, which provides about 40% of the nannofossil
assemblage, certain size reductions related to the hyperthermal events occur. These changes of C.
pelagicus shows a non-linear relationship to the δ13Cbulk record, thereby suggesting a none causal
relation. The large ecophenotypes of C. pelagicus with a small central opening, reflecting maximum
calcification, occur under normal non-hyperthermal - cooler conditions. Samples with the most
negative δ13Cbulk values yield the small ecophenotypes with high total abundance, suggesting a
relationship of warm oligotrophic conditions and hyperthermal events. The elevated temperatures
probably increased the metabolic rate, while the growth is limited by to oligotrophic conditions.
Samples with intermediate δ13Cbulk values show ecophenotypes with medium length and relatively
larger central openings. This ecophenotype is typically found during the ETM2 onset.
Keywords: Eocene, hyperthermal events, morphometry, calcareous nannoplankton
4.1. Introduction
The late Paleocene - early Eocene greenhouse world is marked by three transient hyperthermal
events (e.g. Kennett & Stott, 1991; Thomas et al., 2000; Zachos et al., 2001; Cramer et al., 2003;
Lourens et al., 2005; Sexton et al., 2006; Agnini et al., 2009), occurring during a long term
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CHAPTER IV
warming trend (Nicolo et al., 2007). These hyperthermal events are characterised by carbon isotope
depletion, triggered by orbital forcing (Lourens et al., 2005, Westerhold et al., 2009), causing the
melting of methane clathrates (Dickens et al., 1995; Dickens et al., 1997; Dickens, 2000) and the
decomposition of soil organic carbon in circum-Arctic and Antarctic permafrost (DeConto et al.,
2012). As background temperatures continued to rise following the most pronounced of these
warming events, the Paleocene-Eocene thermal maximum (PETM), the areal extent of permafrost
steadily declined, resulting in a smaller available carbon pool and less intensive hyperthermal events
at each successive orbital forcing maximum (DeConto et al., 2012).
The most intense studied hyperthermal event, the PETM (Kennett & Stott, 1991), occurred
at ~56Ma and had an estimated duration of 196ka (Murphy et al., 2010). It is reflected by a negative
carbon anomaly of ~-3‰, and 3-4°C warming of surface water temperatures (Thomas, 1998). The
Eocene thermal maximum 2 (ETM2) (=Eocene layer of mysterious origin “Elmo”-horizon sensu
Lourens et al. (2005); H1 event sensu Cramer et al. (2003), occurring at ~53.7Ma (Lourens et al.,
2005) is characterised by a negative carbon shift of ~-1.5‰. The third hyperthermal event is the
Eocene thermal maximum 3 (ETM3) (=X-event of Röhl (2005) or K event of Cramer et al. (2003))
shows a negative carbon anomaly of ~-1‰.
All three δ13Cbulk excursions are associated with brown clay-rich layers at Demerara Rise
(Sexton et al., 2011), the δ13Cbulk variability at the ~100-kyr timescale was found to be paced by
eccentricity-modulated precession cycles, with a particularly large-amplitudinal event (=ETM3)
occurring within magnetic anomaly C24n.1n (Sexton et al., 2006).
In addition to these three hyperthermal events, three short termed δ13Cbulk excursions of up
to 1‰ occur during the late Paleocene – early Eocene (Cramer et al., 2003) and are labelled “G”,
“H2” and “J”- events of Cramer et al. (2003).
The effects of elevated CO2 concentrations (Royer et al., 2004; Yapp, 2004) and extreme
warmth on calcareous nannofossils during hyperthermal events are in the focus of an ongoing
debate (e.g. Jiang & Wise, 2006; Mutterlose et al., 2007; Gibbs et al., 2010). Non-quantitative
observations of size changes in coccoliths and “malformation” in nannoliths during the PETM
were interpreted using the acidification experiments of Riebesell et al. (2000). While a 0.25 to
0.45 units decline in surface water pH is possible for the PETM (Ridgwell & Schmidt, 2010),
reconstructed nannoplankton production did not appear to vary significantly across the PETM,
indicating that on geological timescales there is no evidence for interruption of phytoplankton
carbonate production (Gibbs et al., 2010). Latest acidification experiments suggest a rapid (within
~500 asexual generations = 320 days) adaptive evolution in Emiliania huxleyi to higher CO2
concentrations (Lohbeck et al., 2012).
Here we present detailed calcareous nannofossil assemblage records of the ETM2 and
ETM3 and size measurement data of Coccolithus pelagicus, spanning all three hyperthermal events
from the palaeo-equator. This is a key region for the study of the PETM, providing a record of
66
SECTION AND MATERIAL
possible changes of the wind-driven equatorial upwelling system and therefore being important
for the study of global oceanic circulation patterns. Equatorial upwelling systems are archives
for oceanographic changes, which document the complex interplay of ocean chemistry, climate,
circulation and plate tectonics (Van Andel et al., 1977). For the calcareous nannofossil PETMrecord from Demerara Rise see Jiang & Wise (2006) and Mutterlose et al. (2007). The aims of this
study are 1) to assess quantitative data of size-shifts of Coccolithus spp. during the early Eocene, 2) to
provide further evidence of the driving mechanisms of nannofossil assemblage and size shifts during
the early Eocene and 3) to provide a threshold for calcification in calcareous nannofossils, helping
to predict future ocean scenarios with elevated temperature and decreased pH-values.
This biometrical study of calcareous nannofossils supported by isotope geochemistry has been
performed on two cores of ODP Leg 207 Demerara Rise (Fig. 4.1), core 1260A (277.17227.04mbsf, 50.13m) and 1260B (256.16-235.10mbsf, 21.06m) (Fig. 4.2). Site 1260 is
Fig.4.1: Paleogeographic reconstruction (55.0Ma). Location of Demerara Rise and other important PETM
calcareous nannofossil sites, reconstructed from http://www.odsn.de.
located ~380km off the coast of Suriname, South America (9°15’931’’N, 54°32’633’’W),
current water depth 2.548km and reflects an equatorial setting in the Western Atlantic.
The investigated site has a paleolatitude of ~1°S, a paleo-water-depth of upper-abyssal
(~2500 to 3200m), and an average sedimentation rate of 1.5cm/ka (Erbacher et al., 2004).
4.3. Methods
4.3.1. Geochemistry
The calcium carbonate content was measured by using an Eltra CS500 carbon/sulphur analyser
at the department for Geology, Mineralogy and Geophysics at Ruhr-University Bochum. The
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CHAPTER IV
δ13Cbulk values were analysed by Prof. Dr. Michael Joachimski in Erlangen, using a Kiel III carbonate
preparation device.
The random settling technique (Geisen et al., 1999) was applied for a total of 133 samples covering
the two early Eocene hyperthermal events ETM2 and ETM3. A total of 66 samples was studied
from core 1260A (covering the J event of Cramer et al. (2003) and the ETM3) and 67 samples
from the 1260B core (including the ETM2 and the G and H2- events of Cramer et al. (2003))
(Fig.4.2). The abundances were determined by counting >300 specimens/slide and once obtained,
corrected to the total water column within the settling boxes (Geisen et al., 1999). Rare coccolith
species were counted by the acquisition of two additional random traverses of each individual slide,
and counted “X”. All counts were performed by using an Olympus BH-2 light microscope with
cross-polarized light at a magnification of x1,500. Pictures were taken with an Olympus UC30
Digital colour camera.
The size measurements on Coccolithus pelagicus were performed on a total of 142 samples,
spanning the interval from the PETM to the ETM3, by using an Olympus UC30 digital colour
camera in combination with the program “Analysis”. Size measurements of C. pelagicus occurring in
the PETM, J event of Cramer et al. (2003) and ETM3, have been performed on 75 samples from
core 1260A. Calcareous nannofossils from the ETM2, G and H2 – events of Cramer et al. (2003)
have been measured in 67 samples from core 1260B.
For each of the 142 measured samples 50 individuals of the C. pelagicus have been measured
(total length, total width, length of the central opening and width of the central opening), creating
a database of 7,100 measured specimens, resulting in 28,400 data points. Coccolithus pelagicus
is including the well-established taxon Coccolithus pelagicus s. str. and three new described taxa
(Coccolithus latus, Coccolithus foraminis and Coccolithus minimus), established by Bown (2005).
These three taxa are here considered to be ecophenotypes of C. pelagicus. Coccolithus bownii, a
PETM specific taxon, is excluded from the measurements, to ensure consistency of the record.
The size-measurement data have been processed with the program STATISTICA to determine
the mean values of each parameter, 95% confidence and standard deviation; STATISTICA was also
used for K-S/Lilliefors and Shapiro-Wilks W-Tests, for controlling the distribution patterns of the
datasets. The program R was used for further statistical analyses like Spearman-rank correlation
matrices for non-normal distributed data and an ANOVA-analysis of the measured parameters. The
size frequency data has been processed using Analyseries to interpolate and transform the dataset
into regular intervals. The frequency figures have been established on the base of the interpolated
datasets using MatLab.
The diversity of calcareous nannofossils was here quantified as species richness (S),
which is also referred to as simple diversity. Evenness (E) and the Shannon’s diversity index (HS)
68
METHODS
(Shannon,1948)
Fig.4.2: Sampled cores 1260A&B with the
geochemical record (δ13Cbulk), the occurring
hyperthermal events (Paleocene-Eocene
thermal maximum (PETM), Eocene thermal
maximum 2 (ETM2) and Eocene thermal
maximum 3 (ETM3) as well as minor δ13C
excursions (G, H2 & J – events of Cramer
et al., 2003)). The nannoplankton zonation
follows Martini et al., 1971. Sample density
and core photographs are also indicated.
69
CHAPTER IV
have been calculated with PAST (Fig. 4.3). The evenness (E) characterizes the homogeneity of the
assemblage, whereby “0” is one single species preferred and “1” is all species are equal in abundance.
The HS expresses diversity and varies from 0 (community with only a single taxon) to high values
(community with many taxa, each with few individuals). The paleoenvironmental index (PI) index
of Gibbs et al. (2010) is an established nannofossil-based indicator for changes in productivity and
temperature.
The investigated material is housed at the Department of Geology, Mineralogy and Geophysics,
Ruhr-University Bochum.
4.4. Results
4.4.1. Geochemistry
Our composite record from the Demerara Rise 1260 A/B includes all three early Eocene hyperthermal
events (PETM, ETM2 and ETM3) and in addition three minor δ13Cbulk excursions (G, H2 and J).
The G horizon, ETM2 and the H2 horizon are due to minor core losses not present in 1260A.
The PETM is the most pronounced of these events and shows a shift from ~50% CaCO3
and 1.89‰ δ13Cbulk in 1260A 276.91mbsf to 0% CaCO3 and -1.5‰ δ13Cbulk (PETM onset:
1260A 276.87mbsf ). The G horizon is characterised by a decrease from ~50% CaCO3 (1260B,
242.55mbsf ) and 0.63‰ δ13Cbulk (1260B, 242.55mbsf ) to ~30% CaCO3 in 1260B, 242.53mbsf
and 0.23‰ δ13Cbulk in 1260B, 242.52mbsf. The ETM2 shows a shift from ~50% CaCO3 (1260B,
239.23mbsf ) and 1.08‰ δ13Cbulk (1260B 239.23mbsf ) to 30% CaCO3 (1260B 238.89mbsf ) and
0.30‰ (1260B, 238.92mbsf ). The H2 horizon is characterised by a shift from ~50% CaCO3 and a
δ13Cbulk of 1.14‰ in 1260B 238.59mbsf to 0% CaCO3 in 1260B 238.58mbsf and -0.20‰ δ13Cbulk
in 1260B 238.36mbsf. J shows a shift from 53% CaCO3 and a δ13Cbulk 1.04‰ in 1260A 233.35mbsf
to 27.8% CaCO3 and δ13Cbulk of 0.18‰ in 1269A 232.29mbsf. The ETM3 is characterised by a
shift of 41% CaCO3 and 0.58‰ δ13Cbulk in 1260A 227.07mbsf to ~26% CaCO3 and -0.04‰
δ13Cbulk in 1260A 227.01mbsf.
The biometry of C. pelagicus was given from samples covering the entire NP9 to NP12 interval of
Bukry (1973), abundance patterns of calcareous nannofossils were obtained from NP10 to NP12.
The PETM calcareous nannofossil record from Demerara Rise has previously been studied by several
authors (e.g. Jiang & Wise, 2006, Mutterlose et al., 2007) and are therefore not reproduced here.
Three correlation points are included in the NP10 zone: 1260A 250.04mbsf ties to 1260B
253.18mbsf; 1260A 242.08mbsf ties to 1260B 245.63mbsf and 1260A 239.33mbsf ties to
242.58mbsf (Erbacher et al., 2004).
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RESULTS
Fig. 4.3a: 1260B. Geochemical parameters (CaCO3, δ13Cbulk and δ18Obulk), as well as calcareous nannofossil
indices (total abundance, Evenness, Shannon diversity and the Palaeoenvironmental index of Gibbs et al.
(2010)) are depicted in combination with the mbsf, core photographs, NP zones and the occurring events
(G & H2) of Cramer et al. (2003) additionally to the ETM2.
4.4.2.1. Nannofossil diversity indices
G horizon (1260B, 242.52mbsf, NP10): During the G horizon (Fig. 4.3a), characterised by a short
drop of CaCO3, δ13Cbulk, the HS shows a heterogeneity peak of 2.4 for the calcareous nannofossil
assemblages, indicating a diverse community. ETM2 and H2 (1260B, 238.93mbsf, NP11):
Absolute abundances of calcareous nannofossils show constant increase with the onset of the ETM2
(Fig. 4.3b) to 4E+9 specimen. In the overlying H2 horizon, marked by a second negative shift in
the δ13Cbulk record (1260B, 238.58mbsf, NP11), absolute abundances drop to pre-event by values
around 1E+9 species/g sediment. The species richness increases continuously from ~20 species
during the onset of the ETM2 to ~30 above the H2 horizon.
The evenness increases during the early stage of the ETM2 and decreases during the event.
This indicates that more nannofossil species are equally common during the early stage of the
ETM2 (K-mode / stable conditions), than in the later stage. The HS suggests higher heterogeneity
during the early stage of the ETM2,. During the H2 horizon values of the Shannon index suggest
similar high heterogeneity. J horizon (1269A, 232.29mbsf, NP12): The J horizon is characterised
by a decrease of CaCO3 from 53.7% in 233.35mbsf to 27.83% in 232.29mbsf and a δ13Cbulk
shift of 1.04‰ in 233.35mbsf to 0.18‰ in 232.29mbsf. Species richness and Shannon index,
indicating lower heterogeneity (Fig. 4.3c).
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CHAPTER IV
Fig. 4.3b: 1260B. Geochemical parameters (CaCO3, δ13Cbulk and δ18Obulk), as well as calcareous nannofossil
indices (total abundance, Evenness and Shannon diversity are depicted in combination with the mbsf, core
photographs, NP zones and the occurring events (ETM2 and H2 of Cramer et al. (2003).
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RESULTS
Fig. 4.3c: 1260A. Geochemical parameters (CaCO3, δ13Cbulk and δ18Obulk), as well as calcareous nannofossil
indices [total abundance, Evenness, Shannon diversity and the Palaeoenvironmental Index of Gibbs et al.
(2010)] are depicted in combination with the mbsf, core photographs, NP zones and the occurring J event
of Cramer et al. (2003) additionally to the ETM3.
ETM3 (1260A, 227.06mbsf, NP12): Absolute abundances of calcareous nannofossils increase
concomitant to declining δ13Cbulk levels in the early stage of the ETM3. This is followed by a
marked decline to a minimum going along with a minimum of the δ13Cbulk values (Fig. 4.3c). Both
abundances and δ13Cbulk values recover to pre-event values in 226.73mbsf. The species richness
increases to ~35 species while the δ13Cbulk values start to decline and a decreases to ~25 species while
the δ13Cbulk values recover. The evenness data suggest a higher heterogeneity of the nannofossil
assemblage during the ETM3. The HS as well indicates stable conditions during and after the
ETM3.
4.4.2.2. Floral changes during the hyperthermal events
ETM2 & H2: The genus Coccolithus is here subdivided into C. pelagicus s.str. (large specimen >8
µm length), small C. pelagicus (~5µm length), C. latus and C. minimus (<5 μm length). C. pelagicus
s. str., generally appears in abundances below 5%, shows a slightly decrease in values from 1%
at the onset of the event and increasing relative and total abundances during the ETM2 and H2
horizon (Fig. 4a). Small specimens of C. pelagicus show the same pattern of increasing abundances
during the ETM2. During the H2 C. pelagicus shows peak values of 20% of the assemblage,
concomitant to the most negative δ13Cbulk values. C. latus shows a distinctive increase in relative and
total abundance during the onset of the ETM2. Concomitant to the recovery of the δ13Cbulk record
abundance of C. latus decline from 18% to 2% until it increases again, parallel to the decreasing
δ13Cbulk values of the H2 horizon. Toweius spp. displays a drastic increase of total abundances during
the recovery of the δ13Cbulk values in the ETM2. Coronocyclus and Campylosphaera exhibit slightly
enhanced relative and total abundances during both, ETM2 and H2 horizon. Chiasmolithus spp.
shows somewhat enhanced values of 3.5% in the H2 horizon. The discoasters reveal a general trend
to higher abundances during both horizons. Cruciplacolithus cassus yield enhanced total and relative
abundances concomitant to the shift in the δ13Cbulk record.
ETM3: Small C. pelagicus, C. latus and C. minimus show a short lived maximum in relative
and total abundances, paralleled by decreasing δ13Cbulk values (Fig. 4.5). This peak is followed by a
short termed peak of high relative and high absolute abundances in C. pelagicus s.str.. For the rest of
the ETM3 abundances of all Coccolithus taxa decline (C. pelagicus s.str. from 10% in 227.06mbsf
to 6% in 227.02mbsf, C. pelagicus small from 25% in 227.06mbsf to 10% in 227.02mbsf, C. latus
+ C. minimus from 10% in 227.06mbsf to 3% in 227.02mbsf ) before they recover again. The small
C. pelagicus shows higher abundances after the ETM3. Toweius spp. indicates a marked decline in
relative and total abundances during the ETM3. Abundances of Umbilicosphaera ? jordanii fluctuate
around ~5% before the event and rise to 30% of the assemblage during the event. Coronocyclus
bramlettei shows a long-term increase covering the whole event and a short-term decrease in relative
and total abundances concomitant to most negative δ13Cbulk values. The genus Campylosphaera
73
74
Fig. 4.4: Fluctuations of CaCO3, δ13Cbulk, absolute abundances of calcareous nannofossils and abundance of specific nannofossil taxa during the ETM2 and H2 horizon
of Cramer et al. (2003) at Site 1260B.
CHAPTER IV
1260A.
Fig. 4.5: Fluctuations of CaCO3, δ13Cbulk, absolute abundances of calcareous nannofossils and abundance of specific nannofossil taxa during the ETM3 at Site
RESULTS
75
CHAPTER IV
is subdivided into Campylosphaera dela and Campylosphaera eodela. Both species show a marked
increase before the onset of the ETM3, reaching a maximum at the onset of the δ13Cbulk shift,
followed by a decline. Sphenolithus spp. and Discoaster spp. show the same abundance patterns with
slightly higher relative abundances during the recovery of the δ13Cbulk values of the ETM3. C. cassus
shows increased values during the event.
Temperature & Productivity:
G horizon: For the G horizon the paleoenvironmental-index (PI) of Gibbs et al. (2010) indicates
a short-termed drop in productivity and higher temperatures (Fig. 4.3a). H: For the ETM2 the PI
suggests higher productivity at the onset of the event, followed by a shift to higher temperatures and
lower productivity (Fig. 4.3b). The productivity rises and temperature falls with recovering δ13Cbulk
values. With the onset of the H2 horizon temperatures rise again while productivity decreases. The
PI across the J horizon indicates uninfluenced conditions. For the ETM3 the PI suggests lower
productivity concomitant with high temperatures (Fig. 4.3c).
4.4.3. Coccolithus pelagicus biometry
4.4.3.1. Statistical analysis
The statistical analysis of the parameters mean length, mean width, mean central opening length,
mean central opening width and δ13Cbulk where processed with a Spearman-type correlation matrix
for non normal distributed data (Fig. 4.6.). All size measurement parameters show high
Fig. 4.6: Correlation matrix of δ13Cbulk and the mean data of: length, width, length of the central opening
and width of the central opening, from 142 samples.
correlations, with p=0.01 (=99.9% probability) to each other. Mean length and mean width show
high positive correlations (p=0.01) to the δ13Cbulk record. The mean central opening length and
mean central opening width, however, do not show any correlation to the other parameters in the
Spearman matrix.
The scatter plot coccolith length vs. width (Fig. 4.6a) shows a linear relationship of the
parameters with a small range of variability. The central opening length vs. width in contrast shows
a broader range of variability in the relationship, suggesting a tendency towards increased ellipticity
of the central opening in numerous specimens. Neither the total size relationship parameters nor
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RESULTS
the central opening data suggest a clear separation of different species like C. minimus or C. latus
within the genus Coccolithus spp., but a broad morphological range within C. pelagicus.
Fig. 4.7a: Length vs. width and length vs. width (central opening) of all measured C. pelagicus specimen
(n=7,100). 6b: Mixture analyses of the coccoliths length and length of the central opening. Each μm is
separated into three size classes.
The mixture analysis (Fig. 4.6b) for the parameter length indicates three major groups. The
most frequent length is ~6.5µm with a frequency of ~550 specimens. The second and third most
frequent groups are both with a frequency of ~220 specimens, coccoliths with a length of ~4.6 and
~9µm. Mixture analyses for the central opening length, in contrast, suggest two groups. The first
group has a central opening length of ~1.6µm and a frequency of ~540 specimen, while the second
group shows an central opening length of ~2.9µm with a frequency of ~380 specimen.
The scatter plot δ13Cbulk (‰) vs. coccolith mean length (µm) (Fig. 4.7a) indicates a
coefficient of determination of R2=0.1812. In contrast the scatter plot δ13Cbulk (‰) vs. coccolith
mean central opening length (µm) (Fig. 4.7a) shows a coefficient of determination of R2=0.0248,
which is a power of ten smaller than the results for the coccoliths mean length and are therefore not
significant. Figure 4.7b shows the same pattern for δ13Cbulk (‰) vs. coccolith mean width (µm) and
δ13Cbulk (‰) vs. coccolith mean central opening length (µm).
For further analysis of the central opening length and width we decided to split up the dataset to
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CHAPTER IV
use an analysis of variance (ANOVA) (Fig. 4.9). The first model includes all coccolith mean central
opening length and mean central opening width data from samples with a δ13Cbulk of <0.5‰ and
therefore all samples located within the three hyperthermal events. The second model includes all
coccolith mean central opening length and width data of the samples with a δ13Cbulk of >0.5‰ and
therefore all samples not located within the hyperthermal events.
Both models show high significant results (p=0.01), with positive correlation of central
opening length and width to δ13Cbulk for all δ13Cbulk<0.5‰ and negative correlation of central
opening length and width to δ13Cbulk for all δ13Cbulk>0.5‰. In addition to that, both models of
Fig. 4.8a: δ13Cbulk (‰) vs. the mean length (μm) of the coccoliths and δ13Cbulk (‰) vs. the mean length
of the central opening (μm), obtained from all 142 samples. 7b: δ13Cbulk (‰) vs. the mean width (μm) of
the coccoliths and δ13Cbulk (‰) vs. the mean width of the central opening (μm), obtained from all 142
samples.
central opening length and width have been figured (Fig.4.8) and transformed (squared) to achieve
a normal distribution. Both models for δ13Cbulk<0.5‰ and δ13Cbilk>0.5‰ are significantly different.
For the central opening length model 1 and model 2 show significant differences (chi2=81.586;
p<0.001) and similar results for the models of the central opening width (chi2=88.96; p<0.001).
The combination of those for models suggest a small central opening size in the samples with both,
high as well as low δ13Cbulk values, and a maximum of the central opening size concomitant to
intermediate δ13Cbulk values.
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RESULTS
Fig. 4.9: Correlation matrix for model 1, with δ13Cbulk<0.5‰ vs. length and width of the central opening
and model 2 with δ13Cbulk>0.5‰ vs. length and width of the central opening.
Fig. 4.10: Models for δ13Cbulk vs. the mean values of length and width (μm) of the central opening, obtained
from 142 samples. Indicated in red (model 1) are all samples obtained from horizons with a δ13Cbulk<0.5‰,
indicated in blue (model 2) are all samples obtained from horizons with a δ13Cbulk>0.5 ‰.
4.4.3.2. Frequency plots
Coccolithus shows a smaller range of size variation during the peak phase of the PETM, compared
to the pre-PETM interval (Fig. 4.9a C. bownii excluded). The mode (most common value in the
dataset) shifts to slightly lower values at the onset of the PETM. During the recovery phase the
mode shifts to higher values and bigger individuals are therefore abundant. The same pattern can
be observed in the plots including and excluding C. bownii. During the time of the ETM2 onset
small modes of Coccolithus are quite frequent (Fig. 9b).
In the recovery phase of the δ13Cbulk excursion, values for the frequency length and length
minus central opening surprisingly exceed the pre event values. The mode shows a shift to higher
values even while the δ13Cbulk values shift to the negative at the onset of the ETM2. In the H2
horizon the mode shifts to smaller values. During the ETM3 the frequency plots show a shorttermed shift to smaller modes at the base of the event and a subsequent shift to higher frequencies
of individuals with sizes, bigger than in pre-event times (Fig. 4.9c).
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80
Fig. 4.11a: Size measurement data of coccolith length and length of the central opening (mean data, including 95% confidence and standard deviation) plotted
against CaCO3 and δ13Cbulk and the core photo of the PETM. Pictured on the right is the mode (frequency of the measured length excluding the PETM specific
taxon C. bownii and length including C. bownii in μm).
CHAPTER IV
Fig. 4.11b: Size measurement data of coccolith length and length of the central opening (mean data, including 95% confidence and standard deviation) plotted
against CaCO3 and δ13Cbulk and the core photo of the ETM2 and H2 horizon of Cramer et al. (2003). Pictured on the right is the mode (frequency of the
measured lengths in μm).
RESULTS
81
4.5. Discussion
82
Fig. 4.11c: Size measurement data of coccolith length and length of the central opening (mean data, including 95% confidence and standard deviation)
plotted against CaCO3 and δ13Cbulk and the core photo of the ETM3. Pictured on the right is the mode (frequency of the measured lengths in μm).
CHAPTER IV
DISCUSSION
4.5.1. Similarities and differences of the ETM nannofossil floras
Besides the well described PETM excursion floras (e.g. Aubry et al., 2000; Aubry et al., 2001;
Kahn & Aubry, 2004; Raffi et al., 2005; Jiang & Wise, 2006; Mutterlose et al., 2007) only the
large hyperthermal events ETM2 and ETM3 show above background variance. This suggests
that the magnitude of carbon input and associated climate change needs to surpass a threshold to
cause significant biotic disruption (Gibbs et al., 2012). Except for the deep-sea calcareous benthic
foraminiferal record, the PETM is best qualified as a migration and origination event, rather than
an extinction event (Speijer et al., 2012).
In contrast to the PETM there are no specific „excursion“ taxa occurring in the ETM2.
Nevertheless some changes of the floral composition occur. Toweius spp. interpreted to reflect cool,
mesotrophic environments (Mutterlose et al., 2007; Kalb & Bralower, 2012) but is also thought
to have tolerated warmer more oligotrophic environments (Kalb & Bralower, 2012). It shows a
decreasing abundance at the onset ETM2, increasing values throughout the event. The abundance
of Toweius decline decline again with the onset of the H2 indicating a second shift to warm
oligotrophic conditions. Coccolithus shows a shift to ecophenotypes with a larger central opening
(abundant C. latus). The high abundance of C. latus is not only reflected in the percentage but also
reflected in the total abundances. U. ? jordanii and C. cassus can be seen as excursion taxa during
the ETM3. The results from the Hs index suggest no opportunistic taxa are favoured during the G
event of Cramer et al. (2003), ETM2 and ETM3.
4.5.2. Driving mechanisms of the assemblage- and size shifts
Certain PETM excursion taxa (e.g, Rhomboaster spp., Discoaster araneus, Discoaster falcatus) are
thought by several authors to reflect changes of surface ocean pH during the hyperthermal event
(Bybell and Self-Trail, 1995; Jiang and Wise, 2006; Mutterlose et al., 2007; Raffi and De Bernardi,
2008; Raffi et al., 2009; Self-Trail et al., 2012). Indeed the carbonate compensation depth shallowed
during the event (Zachos et al., 2005) and a decline of surface water pH of 0.25 to 0.45units
and a reduction in mean surface-ocean aragonite saturation of Ωa=3 down to 1.5 to 2 is possible
(Ridgwell & Schmidt, 2010). The surface-ocean calcite saturation state (Ωc) in the PETM scenario
suggests a decline of 5.5 to ~4 within a few thousand years (Zeebe, 2012) where the carbon input
only had a moderate impact on the surface-water saturation state (Gibbs et al., 2006; Zeebe et al.,
2009; Gibbs et al., 2010). Lithological and paleontological records from a Paleogene carbonate
platform show no evidence for a carbonate production crisis (Robinson, 2010). Direct effects of
ocean acidification on surface water calcifiers during the PETM may have been limited because
of a relatively slow carbon input rate (Zeebe, 2012). For future scenarios, Zeebe et al. (2008)
predict a decline in surface-ocean pHT of about 0.7units by the year 2300, while surface ocean pHT
has probably not been below 8.1 during the past 2 million years (Hönisch et al., 2009). For the
PETM excursion taxon D. araneus Bown & Pearson (2009) pointed out that it is unlikely a teratoid
(=malformed) form because it lacks a concrete ancestral parent taxon, and is, due to its longevity,
abundance and distribution, quiet successful. Furthermore discoasters (as well as Rhombaster
83
CHAPTER IV
spp.) are nannoliths, not coccoliths and thought to be formed by haptophytes, but probably by a
different biomineralisation process to either heterococcoliths or holococcoliths (Young et al. 1999).
Therefore we doubt that the comparison of malformation in acidification experiments performed
on Emiliania huxleyi and Gephyrocapsa oceanica (Riebesell et al., 2000) and these PETM excursion
taxa is valid. Indeed a comparison to closer related haptophytes like C. pelagicus would be more
plausible. However, malformation as depicted and described in the experiments of Riebesell et al.
(2000) is not observed in Coccolithus spp. during the PETM.
Total nannofossil abundance is not severely negatively impacted by the changes in the
δ13Cbulk or carbonate system during the ETM2. In fact nannofossil abundance during the recovery
of the δ13Cbulk values increase certainly. Our results show a certain trend to smaller ecocphenotypes
of C. pelagicus in the PETM and the lowermost horizon of the ETM3. During the recovery of
the δ13Cbulk values of the ETM2 and ETM3 the coccolith sizes rise quickly, exceeding the mean
values, observed in the non-hyperthermal samples. Most extant species produce a constant number
of coccoliths (7 to 204) per cell (Knappertsbusch, 1993) and the coccolith size is strongly linear
correlated to coccosphere and cell diameter (Henderiks, 2008), implicating smaller cell sizes during
the onset of the hyperthermal events.
4.5.2.1. Productivity
Reconstructed nannoplankton productivity at several sites (ODP Sites 690B Southern Ocean,
1209C tropical Pacific, 1258A tropical Atlantic and Bass River North America) show uninfluenced
values during the PETM interval (Stoll et al., 2007; Gibbs et al., 2010). Our record of total
nannofossil abundances, obtained by the settling slide technique of Geisen et al., (1999), indicates
peak abundances of the smaller ecophenotypes of C. pelagicus (like C. minimus) during the initial
stage of the hyperthermals, indicating a shift from medium abundant big C. pelagicus ecophenotypes
to high abundant small C. pelagicus specimen.
Characteristic of the PETM are warm oligotrophic surface water conditions during the
event (Bralower et al., 2002; Gibbs et al., 2006; Mutterlose et al., 2007). Using the established
nannofossil based paleoenvironmental index of Gibbs et al. (2010) the following horizons G, ETM2
and ETM3 share the same characteristics. In contrast for the ETM2, high productivity as a result of
enhanced nutrient supply from land or upwelling is reported for calcareous nannofossils from the
South Atlantic (Dedert et al., 2011). Our results from the Shannon heterogeneity index, with high
values during the G event, ETM2 and ETM3 indicate a high diversity with many taxa, each with
few individuals. A long-term trend toward smaller cell size in the Oligocene relative to the Eocene
might reflect a response to increased CO2 limitation associated with declining atmospheric CO2
(Henderiks & Pagani, 2008). Zeebe & Ridgwell (2011) point out that this trend would represent a
CO2 related effect on photosynthesis and cell growth rather than on calcification. The discovery of
a heavily calcified E. huxleyi morphotype in modern waters with low pH highlights the complexity
of assemblage-level responses to environmental forcing factors (Beaufort et al., 2011).
84
DISCUSSION
4.5.2.2. Temperature
Temperature is the most important characteristic feature of the hyperthermal events. During the
PETM global temperatures increased by more than 5°C in less than 10,000 years (Zachos et al.,
2008). For the ETM2, based on the TEX86 proxy, the estimated change of sea surface temperature
rose by 3-5°C in the Arctic Ocean (Sluijs et al., 2009). Analyses on stable isotopes in benthic
foraminifers from the Walvis Ridge (Southeast Atlantic Ocean) and Maud Rise (Weddell Sea)
suggest a ~3°C warming for the ETM2 and ~2°C warming for the H2 horizon (Stap et al., 2011).
Fig. 4.12: Model of C. pelagicus morphology vs. δ13Cbulk. Low δ13Cbulk values representing the hyperthermal
events, high values the “normal” conditions.
While small C. pelagicus ecophenotypes appear in the PETM, medium-sized coccoliths with a large
aperture are more abundant in the ETM2.
In contrast to the simple relationship of total coccolith size vs. δ13Cbulk, the size of the central
opening shows a non-linear relation to the δ13Cbulk record. The size data was plotted vs. δ13Cbulk
to depict the relationship between samples with an extreme negative δ13Cbulk value, as it appears
in the hyperthermal events and “normal” δ13Cbulk values (we applied a threshold of 0.5% for the
models). Note that this method is not implicating a direct relationship between total coccolith size
and ocean acidification reflected in the δ13Cbulk shifts, but with the characteristic changes of the
hyperthermal events (higher temperature, local oligotrophy). The combined data of total length and
central opening length suggest a heavily calcified ecophenotype of C. pelagicus (high total length,
small central opening) during the non-event intervals (Fig. 4.10). Heavily calcified morphotypes
of E. huxleyi are dominant in winter, where pH and CaCO3 saturation are lowest (Smith et al.,
2012). Temperature can influence metabolic processes – so that different morphotypes can have
different growth rates at specific temperatures (Langer et al., 2009). Cell size of E. huxleyi and
85
CHAPTER IV
Gephyrocapsa oceanica inversely correlates with temperature (Sorrosa et al., 2005). Low temperature
suppressed coccolithophorid growth but induced cell enlargement and stimulated the intracellular
calcification that produces coccoliths (Sorrosa et al., 2005). The growth rate of E. huxleyi showed a
positive trend with temperature (at 380ppmV and 750ppmV CO2) while a decrease in coccosphere
size in parallel to a decrease in calcification was observed (De Bodt et al., 2010). In contrast to
acidification experiments, temperature had not a significant impact on the morphology of the
coccoliths (De Bodt et al., 2010). Size changes towards smaller specimen in foraminifers during
the PETM are interpreted be the result of elevated temperatures, causing elevated metabolic rates
and food requirements (Alegret et al., 2010). Increased temperatures lead to accelerated metabolic
activity and growth rate in phytoplankton (Lund, 1949; Talling, 1955; Eppley, 1979; Feng et al.,
2012). Some haptophytes are not purely photoautotrophic, but additionally graze on bacteria and
small algae (Kawachi et al., 1991; Jones et al., 1993). This mixotrophic mode of nutrition has
been observed only in species bearing an emergent haptonema, like Coccolithus amongst other
taxa (Jordan, 2012). Small cells are interpreted to grow faster than larger ones (Henderiks, 2008)
and replenish nutrients faster from the surrounding medium (Raven, 1998). Our results from the
PI index suggest oligotrophic conditions during the hyperthermal events. This would predict a
dwarfing of C. pelagicus in oligotrophic sites during the hyperthermal events. Global productivity
gradients, indicate decreased open-ocean productivity, which may have resulted from a widespread
increase in stratification and less efficient biological pumping and increased nutrient availability in
shelf areas, as a result of spatially restricted increased nutrient availability (Gibbs et al., 2006).
4.6. Conclusion
•
In comparison to the PETM, only minor changes of the nannofossil assemblages occur
during the Eocene hyperthermal events ETM2 and ETM3.
•
“Malformed” discoasters are not limited to the hyperthermal events.
•
Opportunistic species are not favoured by hyperthermal conditions.
•
No “excursion” taxa occur during the ETM2.
•
During ETM3 only two species, U. ? jordanii and C. cassus can be seen as “excursion”taxa.
•
High temperature and low productivity, are typical during all three hyperthermal events
and the three minor carbon isotope excursions G, H2 and J.
•
Within the species Coccolithus pelagicus, the three hyperthermals PETM, ETM2 and ETM3
go along with significant size reduction. Morphology shows a non-linear relationship to the δ13Cbulk
record, implying highest calcification (biggest coccoliths) in the non-event samples, formed during
“normal” cooler conditions.
•
Within the intervals of lowest δ13Cbulk values (PETM, ETM2 & ETM3) small Coccolithus
pelagicus ecophenotypes occur in high total abundances (r-strategy), triggered by warm, oligotrophic
86
ACKNOWLEDGEMENTS
conditions during the hyperthermal events at our equatorial study site.
•
Our results suggest a certain impact of the hyperthermal events on nannofossil evolution,
which might help predict future scenarios.
We would like to thank the German program of “Biological Impacts of Ocean Acidification
(BIOACID)” for the financial support, as well as Samantha Gibbs and Sarah O’Dea for their
critical comments and discussion.
87
CHAPTER IV
Fig. 4.13: 1) Toweius callosus; crossed nicols (XN); sample 1260A 29R 5w 5-6; scale bar=5µm; 265.25mbsf.
2) Toweius eminens; XN; sample 1260A 28R 5w 5-6; scale bar=5µm; 255.65mbsf. 3) Toweius occultatus ;
XN; sample 1260A 29R 6w 5-6; scale bar=2µm; 266.75mbsf. 4) Toweius pertusus; XN; sample 1260A 29R
6w 5-6; scale bar=2µm; 266.75mbsf. 5) Toweius serotinus; XN; sample 1260A 29R 6w 5-6; scale bar=5µm;
266.75mbsf. 6) Toweius sp.; XN; sample 1260A 28R 5w 5-6; scale bar=5µm; 255.65mbsf. 7) Prinsius martinii;
XN; sample 1260A 29R 4w 5-6; scale bar=2µm; 263.75mbsf. 8) Prinsius martinii; XN; sample 1260A 29R
5w 5-6; scale bar=2µm; 265.25mbsf. 9) Prinsius martinii; XN; sample 1260A 29R 5w 5-6; scale bar=2µm;
265.25mbsf. 10) Cyclicargolithus luminis; XN; sample 1260A 27R 5w 5-6; scale bar=5µm; 246.06mbsf. 11)
Coccolithus spp. (coccospere); XN; sample 1260A 28R 5w 5-6; scale bar=10µm; 255.65mbsf. 12) Coccolithus
spp. (coccospere); XN; sample 1260A 28R 5w 5-6; scale bar=10µm; 255.65mbsf. 13) Coccolithus pelagicus s.
str.; XN; sample 1260A 29R 6w 5-6; scale bar=5µm; 266.75mbsf. 14) Coccolithus pelagicus s.str.; XN; sample
1260A 27R 2w 57-58; scale bar=5µm; 242.08mbsf. 15) Coccolithus latus; XN; sample 1260A 25R 5w 2627; scale bar=5µm; 226.96mbsf. 16) Coccolithus latus; XN; sample 1260B 12R 3w 39-40; scale bar=5µm;
238.43mbsf. 17) Coccolithus minimus; XN; sample 1260A 29R 6w 5-6; scale bar=2µm; 266.75mbsf. 18)
Coccolithus minimus; XN; sample 1260A 28R 7w 5-6; scale bar=5µm; 258.65mbsf. 19) Coccolithus bownii;
XN; sample 1258C 8R 6w 66-67; scale bar=5µm; 195.36mbsf. 20) Ericsonia robusta; XN; sample 1260A
28R 1w 43-44; scale bar=5µm; 250.04mbsf. 21) Campylosphaera eodela; XN; sample 1260A 38R 7w 5-6;
scale bar=5µm; 258.65mbsf. 22) Campylosphaera dela; XN; sample 1260A 29R 6w 5-6; scale bar=2µm;
266.75mbsf. 23) Campylosphaera differta; XN; sample 1260A 27R 2w 57-58; scale bar=5µm; 242.08mbsf.
24) small Campylosphaera eodela; XN; sample 1260A 29R 6w 5-6; scale bar=2µm; 266.75mbsf. 25) small
Campylosphaera eodela; XN; sample 1260A 29R 6w 5-6; scale bar=1µm; 266.75mbsf. 26) Cruciplacolithus
cassus; XN; sample 1260A 27R 6w 10-11; scale bar=5µm; 247.61mbsf. 27) Cruciplacolithus cassus; XN;
sample 1260A 27R 7w 7-8; scale bar=2µm; 249.08mbsf. 28) Cruciplacolithus cassus; light field; sample
1260A 27R 6w 10-11; scale bar=5µm; 247.61mbsf. 29) Cruciplacolithus primus; XN; sample 1260A 29R
6w 5-6; scale bar=2µm; 266.75mbsf. 30) Chiasmolithus consuetus; XN; sample 1260A 29R 5w 5-6; scale
bar=5µm; 265.25mbsf. 31) Chiasmolithus consuetus; XN; sample 1260A 25R 5w 25-26; scale bar=5µm;
266.95mbsf. 32) Chiasmolithus nitidus; XN; sample 1260A 25R 5w 34-35; scale bar=5µm; 227.04mbsf. 33)
Clausicoccus fenestratus; XN; sample 1260A 25R 5w 33-34; scale bar=5µm; 277.03mbsf. 34) Coronocyclus
bramlettei; XN; sample 1260A 25R 5w 34-35; scale bar=5µm; 227.04mbsf. 35) Umbilicosphaera jordanii;
XN; sample 1260A 27R 4w 5-6; scale bar=5µm; 244.56mbsf. 36) Calcidiscus sp.; XN; sample 1260A 25R
5w 3-4; scale bar=5µm; 226.73mbsf. 37) Calcidiscus sp.; XN; sample 1260A 25R 1w 5-6; scale bar=5µm;
220.75mbsf. 38) Calcidiscus sp.; XN; sample 1260A 25R 3w 99-100; scale bar=5µm; 224.70mbsf. 39)
Pedinocyclus larvalis; XN; sample 1260A 25R 4w 99-100; scale bar=5µm; 226.20mbsf. 40) Ellipsolithus
anadoluensis; XN; sample 1260B 12R 3w 24-25; scale bar=5µm; 238.29mbsf.
88
APPENDIX
Fig. 4.13
89
CHAPTER IV
Fig. 4.14: 1) Ellipsolithus macellus; XN; sample 1260B 12R 3w 33-34; scale bar=5µm; 238.38mbsf. 2)
Jakubowskia leoniae; XN; sample 1260A 25R 1w 99-100; scale bar=5µm; 221.69mbsf. 3) Jakubowskia leoniae;
XN; sample 1260A 27R 7w 5-6; scale bar=5µm; 249.06mbsf. 4) Helicosphaera sp.; XN; sample 1260A 28R
1w 5-6; scale bar=5µm; 249.65mbsf. 5) Helicosphaera bramlettei XN; sample 1260A 27R 7w 7-8; scale
bar=2µm; 249.08mbsf. 6) Pontosphaera sp.; XN; sample 1260A 29R 4w 5-6; scale bar=5µm; 263.75mbsf. 7)
Pontosphaera pulchra; XN; sample 1260A 25R 5w 25-26; scale bar=5µm; 226.95mbsf. 8) Lophodolithus sp.;
XN; sample 1260A 25R 2w 98-99; scale bar=5µm; 223.19mbsf. 9) Neochiastozygus distentus; XN; sample
1260A 29R 1w 5-6; scale bar=5µm; 259.25mbsf. 10) Neochiastozygus rosenkrantzii; XN; sample 1260A
29R 6w 5-6; scale bar=5µm; 266.75mbsf. 11) Neococcolithes protenus; XN; sample 1260A 28R 5w 102-103;
scale bar=5µm; 256.62mbsf. 12) Blackites sp.; XN; sample 1260A 26R 1w 5-6; scale bar=5µm; 230.35mbsf.
13) Blackites sp.2; XN; sample 1260A 25R 6w 99-100; scale bar=5µm; 229.19mbsf. 14) Blackites stilus;
XN; sample 1260A 26R 3w 80-81; scale bar=5µm; 232.60mbsf. 15) Zygrhablithus sp.; XN; sample 1260B
13R 1w 5-6; scale bar=10µm; 242.05mbsf. 16) Zygrhablithus bijugatus; XN; sample 1260A 25R 5w 34-35;
scale bar=5µm; 227.04mbsf. 17) Zygrhablithus bijugatus; XN; sample 1260A 25R 1w 5-6; scale bar=5µm;
220.75mbsf. 18) Zygrhablithus aff. Z. bijugatus nolfii; XN; sample 1260A 27R 2w 5-6; scale bar=5µm;
241.55mbsf. 19) Braarudosphaera aff. B. bigelowii; XN; sample 1260A 29R 2w 5-6; scale bar=5µm;
260.75mbsf. 20) Micrantholithus attenuatus; XN; sample 1260A 26R 7w 52-54; scale bar=5µm; 239.33mbsf.
21) Discoaster sp.1; XN; sample 1260A 25R 1w 5-6; scale bar=5µm; 220.75mbsf. 22) Discoaster sp.1; XN;
sample 1260A 25R 1w 5-6; scale bar=5µm; 220.75mbsf. 23) Discoaster aff. D. okadai Agnini, 2007; XN;
sample 1260A 25R 1w 5-6; scale bar=5µm; 220.75mbsf. 24) Discoaster sp.2; XN; sample 1260B 12R 3w
41-42; scale bar=5µm; 238.45mbsf. 25) Discoaster sp.2; XN; sample 1260B 12R 3w 54-55; scale bar=5µm;
238.58mbsf. 26) Discoaster salisburgensis; XN; sample 1260A 28R 5w 5-6; scale bar=5µm; 255.65mbsf. 27)
Discoaster lodoensis; XN; sample 1260B 12R 3w 17-18; scale bar=5µm; 238.22mbsf. 28) Discoaster lodoensis;
light field; sample 1260B 12R 3w 17-18; scale bar=5µm; 238.22mbsf. 29) Discoaster aff. D. mohleri; XN;
sample 1260A 25R 5w 34-35; scale bar=5µm; 227.04mbsf. 30) Discoaster diastypus XN; sample 1260B 12R
3w 17-18; scale bar=5µm; 238.22mbsf. 31) Discoaster diastypus XN; sample 1260B 12R 3w 41-42; scale
bar=10µm; 238.45mbsf. 32) Discoaster sp. 3; XN; sample 1260A 25R 1w 5-6; scale bar=5µm; 220.75mbsf.
33) Discoaster delicatus; XN; sample 1260A 27R 6w 10-11; scale bar=5µm; 247.61mbsf. 34) Discoaster
multiradiatus; XN; sample 1260A 25R 5w 28-29; scale bar=5µm; 226.98mbsf. 35) Discoaster kuepperi; XN;
sample 1260A 25R 5w 26-27; scale bar=5µm; 226.96mbsf. 36) Discoaster kuepperi; XN; sample 1260A 25R
5w 26-27; scale bar=5µm; 226.96mbsf. 37) Discoaster pacificus; XN; sample 1260B 12R 3w 54-55; scale
bar=5µm; 238.58mbsf. 38) malformed Discoaster; light field; sample 1260A 28R 5w 6-7; scale bar=5µm;
255.65mbsf. 39) malformed Discoaster; light field; sample 1260A 29R 6w 5-6; scale bar=5µm; 266.75mbsf.
40) malformed Discoaster; light field; sample 1260B 12R 3w 33-34; scale bar=5µm; 238.38mbsf.
90
APPENDIX
Fig.4.14
91
CHAPTER IV
92
Fig. 4.15: 1) malformed Discoaster; light field; sample 1260A 25R 1w 99-100; scale bar=5µm;
221.69mbsf. 2) malformed Discoaster; light field; sample 1260B 12R 3w 76-77; scale bar=10µm;
238.81mbsf. 3) Fasciculithus tympaniformis; XN; sample 1260A 27R 7w 5-6; scale bar=5µm;
249.06mbsf. 4) Fasciculithus thomasii; XN; sample 1260A 27R 7w 5-6; scale bar=5µm; 249.06mbsf.
5) Fasciculithus alanii; XN; sample 1260A 27R 7w 5-6; scale bar=5µm; 249.06mbsf. 6) Tribrachiatus
orthostylus; XN; sample 1260A 25R 5w 25-26; scale bar=5µm; 226.95mbsf. 7) Tribrachiatus digitalis;
XN; sample 1260B 13R 1w 55-56; scale bar=5µm; 242.55mbsf. 7) aff. Tribrachiatus contortus; XN;
sample 1260A 26R 5w 5-6; scale bar=5µm; 234.85mbsf. 8) Tribrachiatus contortus; XN; sample
1260A 26R 5w 5-6; scale bar=5µm; 234.85mbsf. 9) Sphenolithus sp.1 ; XN; sample 1260A 26R
1w 5-6; scale bar=5µm; 230.35mbsf. 10) Sphenolithus sp.1; light field; sample 1260A 26R 1w
5-6; scale bar=5µm; 230.35mbsf. 11) Sphenolithus moriformis; XN; sample 1260A 25R 4w 99100; scale bar=2µm; 226.20mbsf. 12) Sphenolithus aff. S. furcatolithoides; XN; sample 1260A 25R
1w 5-6; scale bar=5µm; 220.75mbsf. 13) Sphenolithus aff. S. furcatolithoides; XN; sample 1260A
25R 1w 5-6; scale bar=5µm; 220.75mbsf. 14) Sphenolithus aff. S. furcatolithoides; XN; sample
1260A 25R 4w 5-6; scale bar=5µm; 225.25mbsf. 15) Sphenolithus aff. S. furcatolithoides; XN;
sample 1260A 25R 1w 5-6; scale bar=5µm; 220.75mbsf. 16) Sphenolithus distentus; XN; sample
1260A 25R 4w 5-6; scale bar=5µm; 225.25mbsf. 17) Sphenolithus distentus; XN; sample 1260A
25R 5w 30-31; scale bar=5µm; 227.00mbsf. 18) Sphenolithus arthurii; XN; sample 1260A 25R
5w 30-31; scale bar=5µm; 227.00mbsf. 19) Sphenolithus radians; XN; sample 1260A 26R 6w
5-6; scale bar=5µm; 236.35mbsf. 20) Sphenolithus conspicuus; XN; sample 1260B 12R 3w 3334; scale bar=5µm; 238.38mbsf. 21) Sphenolithus conspicuus; XN; sample 1260B 12R 3w 33-34;
scale bar=5µm; 238.38mbsf. 22) Unknown species 1; XN; sample 1260A 25R 5w 34-35; scale
bar=5µm; 227.04mbsf. 23) Unknown species 1; XN; sample 1260A 25R 5w 34-35; scale bar=5µm;
227.04mbsf. 24) Unknown species 2; XN; sample 1260A 25R 3w 5-6; scale bar=5µm; 223.75mbsf.
1260A (mbsf)
3
x
0.29
0.51
0.18
0.45
232,05
232,29 28
232,54
2
6
2
6
4
x
x
x
x
x
1
1
1
58
99
79
70
120
115
114
125
X 134
2 133
2 114
2
62
31
40
32
26
49
Toweius serotinus
1
2
1
1
2
1
X
6
X
2
4
X
1
2
X
8
6
5
2
6
5
8
3
2
2
X
1
X
4
1
1
1
1
6
Coccolithus pelagicus s.str.
9
14
22
19
15
12
27
22
27
6
14
10
9
6
27
16
32
28
27
21
22
24
24
19
18
26
18
6
8
12
7
8
9
23
Coccolithus pelagicus (small)
30
24
29
21
23
13
25
33
27
30
22
37
53
75
47
31
24
27
28
32
35
38
18
31
39
61
52
62
52
26
20
18
27
8
Coccolithus latus
17
16
7
5
7
13
15
3
8
3
7
10
18
15
8
7
12
3
10
7
8
10
3
9
8
10
7
3
6
4
3
7
9
20
1
Ericsonia robusta
16
20
19
9
26
23
42
14
15
31
18
25
21
13
24
30
44
24
23
22
22
12
14
7
12
9
11
5
8
8
1
6
5
Campylosphaera dela (big)
1
4
2
1
9
8
2
3
1
5
X
X
16
7
6
8
8
3
4
4
5
2
X
2
3
6
2
1
1
1
1
Coccolithus minimus
Fig. 4.16a: Nannofossil results 1260A
0.91
0.89
230,40
5
231,85 53
15
x
x
0.57
0.78
229,75
230,35 59
7
11
x
x
0.93
0.65
228,25 48
229,19
8
3
x
0.67
0.83
227,09 44
x
6
3
x
x
6
X
x
x
227,68 59
0.27
0.58
227,06 36
227,07 41
0.18
x
227,03 29 -0.28
0.21
3
x
0.04
227,02 26
227,04 31
14
1
x
227,01 26 -0.04
227,05 34
14
2
x
38
34
227.00 27 -0.05
X
X
X
x
42
x
1
45
32
0.10
1
X
95
31
226,98 31 -0.01
2
1
1
226,99 30
226,97 32
7
1
0.34
0.19
226,95 35
226,96 35
x
2
1
x
x
x
0.69
0.28
226,73
226,89 45
86
3
1 116
2 119
1 140
3
1
181
140
x
X
86
167
x
Size measurements
1.00
1
1
2
Toweius eminens
0.88
0.81
224,70 39
2
1
Toweius occultatus
225,25
1.01
223,75
Toweius callosus
1
Toweius pertusus
226,20 45
1.01
0.82
222,25
223,19
1.12
13
1.17
Calcium carbonate (%)
220,75
δ C (‰)
221,69 59
70
Campylosphaera eodela (small)
24
40
23
47
41
41
26
42
38
51
55
46
41
37
53
23
23
29
32
29
33
38
30
19
26
23
25
32
42
20
45
31
36
Campylosphaera differta
X
1
1
1
1
Cruciplacolithus ? cassus
4
4
1
1
6
9
10
16
18
8
6
6
8
14
10
15
18
19
11
16
14
12
18
8
13
8
8
8
8
14
8
5
5
21
1
1
1
X
1
1
X
2
3
X
1
X
1
X
X
1
X
5
1
X
1
1
1
X
3
2
5
4
5
5
6
4
4
5
14
7
2
6
4
6
5
7
7
6
6
6
6
14
10
6
10
7
2
10
7
4
3
2
1
1
5
X
4
4
4
2
3
1
54
19
18
21
22
17
26
15
21
29
21
42
45
43
26
28
28
21
23
41
38
38
37
50
49
54
28
45
22
23
41
48
37
24
32
13
30
29
22
30
13
10
17
9
15
20
33
28
55
90
84
60
37
41
38
36
53
20
40
5
5
3
3
3
5
2
6
Calcidiscus sp.
X
X
1
X
X
X
2
Pedinocyclus larvalis
1
4
1
2
3
3
1
3
1
2
2
3
3
2
1
5
4
3
3
6
9
2
2
2
X
2
3
X
2
Ellipsolithus spp.
3
1
1
1
1
1
1
X
1
2
1
1
1
1
X
1
X
2
X
2
1
1
X
1
2
X
X
1
Jakubowskia leoniae
1
X
X
1
Pontosphaera spp.
X
X
1
Pontosphaera sp.1
4
4
2
X
1
2
1
1
2
X
X
3
1
Pontosphaera punctosa
X
Pontosphaera pulchra
1
1
1
1
X
2
2
5
3
11
5
6
6
3
9
8
3
2
1
1
X
1
1
Lophodolithus spp.
X
X
Lophodolithus sp.1
X
X
1
1
1
2
1
1
1
1
1
3
X
Lophodolithus aff. rotundus
X
X
X?
1
1
2
1
X
3
1
X
2
1
1
1
1
1
2
1
X
Blackites spp.
X
Blackites ? stilus
X
1
X
Blackites sp.2
3
X
X
X
2
aff. Laternithus
X
1
1
X
3
3
5
X
Zygrhablithus spp.
2
1
1
X
2
X
4
1
X
Zygrhablithus bijugatus
1
X
Micrantholithus attenuatus
1
APPENDIX
93
Braarudosphaera aff. B. bigelowii
Braarudosphaera bigelowii
Zygrhablithus aff. Z. bijugatus nolfii
Zygodiscus spp.
Helicosphaera spp.
Neocrepidolithus grandiculus
1
1
228,25
1
1
3
232,05
232,29
232,54
1
1
3
1
230,40
231,85
X
1
X
230,35
229,75
229,19
1
2
X
227,09
227,68
1
227,07
2
1
X
2
1
3
1
6
5
3
3
2
1
2
5
3
227,06
227,05
2
5
3
227,03
3
2
1
4
8
227,04
2
2
227,01
227,02
1
2
227.00
1
2
X
226,98
226,99
1
X
226,96
1
226,97
X
226,89
226,95
2
2
6
X
1
8
226,20
1
7
226,73
225,25
2
1
2
X
1
X
1
8
5
223,75
1
Discoaster sp.2
224,70
2
2
Discoaster sp.3
5
2
222,25
Discoaster sp.1
7
Discoaster aff. D. mohleri
223,19
3
1260A (mbsf)
4
Discoaster spp.
220,75
malformed Discoaster aff. D. mohleri
1
2
1
1
3
1
2
1
2
2
2
2
1
1
1
3
1
1
1
2
1
X
1
2
1
X
1
1
1
X
1
2
1
1
X
X
1
Discoaster kuepperi
Discoaster pacificus
X
2
1
2
5
1
1
1
1
2
5
3
3
9
4
5
6
3
2
4
1
1
1
4
4
5
3
2
8
2
6
8
1 12
X 18
7
8
5
15
1
1
1
1
3
Discoaster falcatus
malformed D. barbadiensis
malformed Discoaster multiradiatus
Fig. 4.16b: Nannofossil results 1260A
94
221,69
Discoaster mediosus
1
Discoaster lodoensis
1
2
X
X
X
2
X
1
1
2
X
Discoaster aff. D. okadai
1
2
malformed discoasters
2
3
2
1
4
2
3
2
4
3
3
3
1
3
1
5
2
5
Bomolithus sp.
1
1
1
1
1
1
1
1
1
1
2
2
1
1
Tribrachiatus orthostylus
1
1
2
10
6
3
3
2
1
1
2
2
1
1
Sphenolithus sp.1
18
9
8
5
11
12
8
16
15
6
4
12
3
5
6
9
14
13
13
7
10
13
21
15
8
12
16
17
16
15
8
8
7
X 18
2
1
1
3
6
5
1
1
1
1
1
X
Sphenolithus radians
3
9
4
9
3
9
17
7
7
4
5
6
6
11
10
15
14
18
13
9
14
16
25
6
10 19
8 10
4
2 12
1 18
5
3
1
X 26
2 17
1 15
X 10
1 10
5
3 10
Sphenolithus conspicuus
1
Sphenolithus distentus
2
1
2
2
1
1
1
1
1
1
3
Sphenolithus arthurii
X
1
2
Sphenolithus aff. S. furcatolithoides
1
2
Biantolithus spp.
X
Octolithus sp.
1
1
1
Prinsius c.f. Prinsius martinii
3
X
X
1
X
1
1
1
Unknown species 1
X
358
Counted individuals
Unknown species 2
319
322
317
350
323
336
315
328
316
315
X 308
309
313
312
322
322
326
333
322
334
326
338
316
304
317
341
347
314
353
356
331
339
333
35
simple diversity
25
28
25
25
28
26
31
32
31
25
32
23
26
23
28
28
29
25
29
36
37
35
28
28
35
32
34
30
38
39
28
25
30
Water volume V [ml]
Sample weight [mg]
22.90 500 0.0229
Mass of sediment M [g]
Fields of view
26 0.000141
25 0.000141
30 0.000141
32 0.000141
31 0.000141
27 0.000141
45 0.000141
22 0.000141
28 0.000141
Surface area [cm2]
21.60 500 0.0216
18.53 500 0.0185
19.01 500 0.0190
19.69 500 0.0197
19.32 500 0.0193
19.85 500 0.0199
17.80 500 0.0178
17.14 500 0.0171
19.60 500 0.0196
18.12 500 0.0181
20.52 500 0.0205
19.35 500 0.0194
17.75 500 0.0178
18.64 500 0.0186
19.05 500 0.0191
17.00 500 0.0170
22.20 500 0.0222
19.50 500 0.0195
20.60 500 0.0206
19.80 500 0.0198
19.60 500 0.0196
19.20 500 0.0192
18.20 500 0.0182
19.10 500 0.0191
27 0.000141
40 0.000141
19 0.000141
23 0.000141
22 0.000141
18 0.000141
36 0.000141
21 0.000141
28 0.000141
29 0.000141
41 0.000141
32 0.000141
33 0.000141
27 0.000141
65 0.000141
73 0.000141
82 0.000141
49 0.000141
37 0.000141
52 0.000141
57 0.000141
63 0.000141
65 0.000141
80 0.000141
18.40 500 0.0184 113 0.000141
17.37 500 0.0174
18.44 500 0.0184
18.83 500 0.0188
19.80 500 0.0198
17.77 500 0.0178
18.49 500 0.0185
17.73 500 0.0177
22.71 500 0.0227
2
Height of water column [cm]
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
989,943,501
Particles per g sediment [n/g]
969,826,538
770,267,115
1,556,124,858
1,370,299,150
1,347,390,917
1,667,351,472
871,583,393
1,615,714,518
1,020,925,087
1,062,858,031
649,098,192
884,806,751
947,442,662
1,099,172,408
461,071,662
460,049,948
317,520,426
617,923,110
749,044,852
575,173,448
517,377,537
495,445,420
473,612,585
352,753,333
270,323,556
1,338,758,091
1,334,594,852
985,550,697
987,825,955
1,145,834,178
1,175,569,242
753,354,427
1,181,749,193
J
ETM3
T. orthostylus
Comments
BASE NP12FO Discoaster lodoensis
NP12
NP12
CHAPTER IV
Biantholithus flosculus
Tribrachiatus contortus
Fasciculithus spp.
276.87
276.71
1.47
266.75
276.59
1.18
1.32
263.75
1.37
262.25 60
265.25 59
1.64
1.56
1.65
258.80
259,25 64
1.58
258.65 63
260.75
1.48
1.34
256.62 67
1.20
255.65
257.15
1.24
254.15 59
1.41
250,04
1.33
1.32
249.65 62
1.24
1.21
249.08
251.15 59
2.16
249.06 45
252.65
1.10
1.25
246.06 64
247.61
1.27
1.20
243.06 64
1.13
242.08
244.56
1.20
241.55
0.84
237.85
0.72
0.75
236.35 43
0.89
0.98
234.85
239,33 52
1.04
233.35 54
240,05
0.64
0.70
232.60 41
232,65
X
X
2
2
7
3
1
5
3
11
6
2
1
4
7
5
6
3
6
3
8
13
7
10
6
2
7
x
6
2
x
6
8
3
x
x
3
1
3
6
2
4
1
3
2
3
X
X
24
3
3
6
1
2
X
2
2
1
1
1260A (mbsf)
Calcium carbonate (%)
13
δ C (‰)
Toweius callosus
Size measurements
Toweius eminens
160
143
200
197
3 189
3 196
2 178
3 164
1 182
2 184
1 166
5 190
5 227
2 192
X 208
2 174
X 208
21 146
3 155
2 115
2 126
3 162
2 154
1 108
130
X 152
2 164
169
129
2 140
Toweius occultatus
135
1 153
X
2
2
3
8
6
1
4
1
4
X
6
3
6
3
9
5
18
4
7
5
4
3
2
2
1
1
2
2
2
1
2
Toweius pertusus
Toweius serotinus
1
3
15
90
67
63
60
60
66
71
68
69
76
53
45
55
44
39
35
36
62
70
47
41
39
53
47
33
34
60
40
22
33
19
15 104
10
8
17
12
16
12
30
25
22
22
20
19
21
26
21
46
40
57
60
33
54
33
29
21
33
40
26
35
8
10
8
2
5
4
8
10
8
8
8
13
5
6
2
3
5
5
4
2
8
6
3
5
2
3
2
8
10
13
2
11
9
11
Coccolithus pelagicus s.str.
Coccolithus latus
5
9
4
8
11
12
9
17
2
10
9
4
6
1
2
5
1
6
2
8
8
9
3
9
5
Coccolithus minimus
1
17
Fig. 4.16c: Nannofossil results 1260A
95
1
Ericsonia robusta
12
12
10
2
8
7
5
11
4
3
5
5
2
4
3
4
3
4
6
4
10
4
3
6
10
10
9
9
12
9
14
21
15
23
17
12
13
3
14
1
4
2
3
8
10
17
8
13
2
3
4
15
10
14
26
18
27
13
22
33
20
14
10
2
1
2
3
X
1
3
6
11
1
2
7
7
8
4
1
1
1
2
1
2
1
1
2
1
1
1
3
X
1
1
1
2
2
1
1
1
1
2
1
2
1
X
1
2
X
1
2
X
2
2
2
2
1
X
7
5
3
1
3
1
1
8
3
2
8
8
6
19
5
8
10
6
10
3
6
7
7
3
7
7
7
5
9
7
8
10
18
10
5
26
11
14
25
17
35
22
6
2
8
4
5
20
8
8
19
23
21
19
14
23
Calcidiscus sp.
X
1
1
1
1
Ellipsolithus spp.
2
X
2
X
1
1
1
X
1
1
2
Jakubowskia leoniae
1
1
1
1
Helicosphaera spp.
Pontosphaera spp.
1
1
Pontosphaera sp.1
1
1
2
1
1
Lophodolithus spp.
Lophodolithus sp.1
1
3
1
2
1
1
1
Lophodolithus aff. rotundus
2
Zygodiscus spp.
1
X
1
1
8
2
2
2
1
2
X
3
3
2
5
1
1
1
1
1
X
1
1
1
1
1
1
2
2
2
1
1
4
1
1
1
1
2
4
1
Blackites spp.
X
Blackites ? stilus
X
Blackites sp.2
aff. Laternithus
6
Zygrhablithus spp.
2
1
1
Zygrhablithus aff. Z. bijugatus nolfii
1
2
1
1
Braarudosphaera aff. B. bigelowii
5
1
APPENDIX
1260A (mbsf)
Discoaster spp.
1
Discoaster sp.2
Discoaster sp.3
3
malformed Discoaster multiradiatus
1
1
1
malformed Discoaster aff. D. mohleri
1
1
1
1
1
1
1
2
4
2
4
1
1
X
1
1
1
1
2
2
X
X
8
8
3
10
6
5
10
10
15
16
8
15
12
25
25
16
37
17
9
11
8
3
2
276.87
276.71
276.59
266.75
11
2
1
265.25
1
X
17
6
11
8
1
4
262.25
263.75
4
1
3
1
1
1
2
1
4
3
3
1
4
1
4
4 10
20
7
1
1
2
19
1
260.75
1
1
Bomolithus sp.
1
1
259,25
1
1
4
2
X
1
X
1
Sphenolithus sp.1
4
258.65
X
1
1
1
2
2
6
Fasciculithus spp.
1
X
1
258.80
1
5
2
255.65
256.62
257.15
3
254.15
252.65
1
4
3
250,04
1
249.65
251.15
2
4
249.08
1
1
249.06
1
1
1
247.61
1
1
1
246.06
244.56
1
X
4
1
1
2
1
2
1
1
1
3
1
1
1
2
Discoaster kuepperi
2
malformed D. barbadiensis
2
3
X
X
Discoaster mediosus
242.08
1
6
1
2
2
1
243.06
1
1
X
Discoaster aff. D. okadai
2
3
1
2
241.55
240,05
1
1
237.85
239,33
1
236.35
1
X
234.85
X
3
2
3
233.35
2
Discoaster sp.1
3
232.60
Discoaster falcatus
Fig. 4.16d: Nannofossil results 1260A
96
232,65
1
2
1
1
2
2
8
Sphenolithus radians
5
7
3
6
10
7
3
6
6
Biantholithus flosculus
1
1
1
2
1
6
1
1
1
2
2
1
322
Counted individuals
363
351
346
326
358
359
323
315
337
334
325
326
323
350
342
322
310
342
313
342
333
343
322
368
318
328
337
403
320
338
308
30
simple diversity
21
20
18
19
22
18
19
16
20
17
18
17
19
21
19
19
21
28
26
25
23
24
27
25
20
31
25
30
27
27
21
Water volume V [ml]
Sample weight [mg]
16.48 500 0.0165
18.80 500 0.0188
22.53 500 0.0225
19.96 500 0.0200
22.04 500 0.0220
23.40 500 0.0234
15.68 500 0.0157
18.39 500 0.0184
17.35 500 0.0174
16.89 500 0.0169
17.27 500 0.0173
19.80 500 0.0198
20.64 500 0.0206
19.91 500 0.0199
19.19 500 0.0192
18.73 500 0.0187
15.60 500 0.0156
15.03 500 0.0150
19.45 500 0.0195
18.73 500 0.0187
20.20 500 0.0202
20.55 500 0.0206
18.80 500 0.0188
16.06 500 0.0161
19.35 500 0.0194
17.02 500 0.0170
16.26 500 0.0163
19.89 500 0.0199
18.74 500 0.0187
16.61 500 0.0166
18.36 500 0.0184
16.23 500 0.0162
55
Fields of view
19
14
13
22
11
13
18
25
19
23
19
24
29
16
20
19
19
26
17
19
25
25
25
18
34
35
13
14
28
40
49
0.000141
Surface area [cm2]
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
629,878,625
1,801,839,365
1,973,053,153
2,364,248,410
1,192,076,770
2,466,013,104
3,122,668,871
1,730,091,944
1,287,632,595
1,861,947,993
1,490,895,450
1,531,741,453
1,166,856,800
991,868,642
2,021,128,765
1,618,747,941
1,926,187,536
1,924,730,854
1,199,096,260
1,742,924,340
1,579,945,229
1,149,246,777
1,293,948,997
1,421,972,567
1,873,334,107
974,337,781
1,021,894,717
2,310,854,819
2,723,505,897
1,219,953,312
816,027,751
686,684,133
FO T. bramlettei
FO D. diastypus
Reworked Fasciculuthus
T. contortus subzone of Aubry, 1995
Comments
NP9a
PETM onset
(Aubry et al., 2000)
NP9a/9b FO Discoaster araneu s
NP10
NP10
NP10
NP10d
NP10d
BASE NP11LO of T. contortus
NP11
CHAPTER IV
Unknown species 2
Unknown species 1
Octolithus sp.
Biantolithus spp.
Sphenolithus aff. S. furcatolithoides
Sphenolithus arthurii
0.64
0.66
0.72
0.59
0.30
0.53
0.38
0.44
0.49
0.61
0.55
1.03
1.02
0.93
0.98
1.01
0.99
0.97
0.89
0.92
0.78
0.90
0.83
0.73
0.78
0.77
0.85
0.81
0.63
0.77
0.75
0.64
0.66
0.74
1
1
1
4
2
1
4
X
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Size meaasurement
1
1
1
1
1
2
3
5
2
1
Toweius callosus
X
X
X
X
X
X
X
X
X
X
X
Toweius pertusus
Toweius eminens
130
143
112
105
110
103
110
170
134
161
118
172
173
169
188
193
191
169
177
175
2 203
195
163
169
160
180
169
145
137
159
164
133
110
119
Coccolithus pelagicus s. str.
3
X
1
2
1
1
1
X
1
1
1
1
1
1
6
5
5
5
6
13
11
8
9
3
20
10
6
17
11
7
10
8
4
7
10
9
29
7
6
8
3
5
3
1 4
1
X 8
7
Toweius serotinus
1
43
27
27
36
46
70
55
50
32
20
29
25
29
21
20
27
28
27
25
27
24
36
38
36
52
38
41
76
27
34
28
35
34
32
Coccolithus latus
4
17
9
6
7
11
25
33
13
12
8
2
8
5
6
5
2
1
2
2
4
4
4
9
16
25
12
6
19
7
10
9
13
16
1
3
2
1
1
1
1
3
1
1
1
2
2
2
3
1
2
Coccolithus minimus
Coccolithus crucis
1260B (mbsf)
Fig. 4.17a: Nannofossil results 1260B
δ13C (‰)
237,25
238,22
238,26
238,29
238,33
238,37
238,41
238,45
238,49
238,53
238,57
238,60
238,61
238,62
238,63
238,64
238,65
238,66
238,67
238,68
238,69
238,70
238,71
238,72
238,73
238,74
238,75
238,76
238,77
238,78
238,79
238,80
238,81
238,82
17
8
9
13
7
7
9
7
10
10
7
8
6
6
19
13
9
14
6
9
5
11
7
12
8
6
3
12
6
6
2
14
16
18
26
55
45
30
38
29
36
43
34
39
45
32
30
38
43
26
9
18
34
39
17
23
26
25
21
16
44
29
46
32
56
60
65
58
1
1
X
X
1
6
6
10
17
14
16
17
11
10
12
8
19
19
5
10
10
4
9
8
9
3
8
X
15 X
10
12
5
2
7
11
7
6
3
4
Chiasmolithus rosenkrantzii
3
10
1 2
1 4
6
4
6
3
8
2
1 10
2 11
2 6
1 2
2
X 3
2
X 6
X 1
X 2
X 5 X
2
1
1 3
2 4
4
1
4
3
8
X 1
1 5
3
X 4
1
16
5
21
22
14
9
30
7
14
16
20
16
6
19
8
22
14
18
10
21
8
16
26
14
12
27
15
7
32
33
26
29
30
29
Coronocyclus sp.1 (thicker)
7
9
6
5
4
3
5
1
14
11
27
26
17
10
16
8
8
15
10
16
15
10
12
4
15
9
14
18
7
11
20
15
8
1
2
3
X
2
1
2
8
4
3
7
2
4
12
2
10
1
8
4
6
10
4
4
3
9
3
Calcidiscus sp.
1
3
1
1
X
3
4
2
1
4
3
2
4
2
1
1
1
2
2
5
4
1
7
3
3
2
Calcidiscus bicircus
1
2
1
X
1
1
4
X
3
2
1
6
7
3
2
Ellipsolithus anaduloensis
1
4
1
X
X
1
2
2
3
X
1
X
1
X
X
X
1
1
X
X
2
X
2
1X
X
X
1X
Jakubowskia leoniae
1
1
X
1
1
1
X
X
X
1
Pontosphaera spp.
1X
X
1
2
2
1
2
1
2
X
X
X
1
X
X
X
2
2
X
X
1
3
1
X
X
X
X
X
X
X
X
X
X
X
1
X
1
1
1
X
1
1
1
1
1
X
1
1
1
2
X
X
1
X
2
X
X
2
1
2
Calciosolenia spp.
1
1
1
Blackites sp. 1
2
1
1
1
1
1
X
X
1
X
X
2
1
X
2
3
3
5
X
2
X
1
3
1 3
7
4
7
Syracosphaera ? tanzanensis
1
1
1
X
X
X
1
1
Zygrhablithus bijugatus cornutus
X
X
APPENDIX
97
Micrantolithus sp.
Zygrhablithus sp.
Semihololithus sp.1
Blackites stilus
Blackites sp. 2
Ellipsolithus spp.
1
2
1
1
4
3
1
1
3
X
X
X
X
1
X
1
2
2
X
2
2
1
2
X
X
Discoaster sp. 1
1
Discoaster sp. 2
X
3
2
1
1
1
1
2
2
3
2
1
5
2
1
2
3
5
4
4
2
2
X
2
9
2
2
X
X
Discoaster sp. 3
2
3
4
1
X
X
1
2
X
1
2
2
1
X
X
X
X
1
1
X
X
1
X
X
X
2
X
3
6
1
2
5
Discoaster kuepperi
5
2
1
1
3
1
3
X
2
2
4
1
1
1
1
2
1
3
1
2
5
2
5
X
4
3
4
5
3
1
Discoaster spp.
1260B (mbsf)
Fig. 4.17b: Nannofossil results 1260B
98
237,25
238,22
238,26 1
238,29
238,33
238,37 1
238,41
238,45
238,49
238,53
238,57
238,60
238,61
238,62
238,63
238,64
238,65
238,66
238,67
238,68
238,69
238,70
238,71
238,72
238,73
238,74
238,75
238,76
238,77
238,78
238,79
238,80
238,81
238,82
1
X
X
1
1
1
1
X
X
X
X
X
X
X
4
X
X
2
X
X
X
X
X
2
X
X
X
X
X
1
X
1
1
X
1
X
X
4
3
X
1
X
X
1
1
X
1
X
X
X
X
1
X
X
1
2
1
X
X
X
X
1
X
10
7
8
10
10
10
10
10
9
17
14
7
9
13
11
10
8
6
6
4
7
9
15
5
7
9
6
15
8
7
7
13
8
18
3
1
2
2
1
1
1
3
2
2
2
2
2
5
1
1
3
5
4
2
1
4
2
1
2
1
X
2
1
4
11
9
11
11
8
16
6
11
8
2
3
6
3
1
8
7
2
2
4
3
4
3
1
5
3
4
2
4
8
8
8
3
X
X
1
1
2
1
1
2
2
3
1
1
3
4
2
1
X
2
1
1
1
3
2
3
2
5
3
2
3
2
Counted individuals
124
146
163
164
144
127
148
143
136
149
154
124
120
124
118
103
92
100
105
114
73
93
115
103
90
93
90
100
129
122
133
157
149
153
Simple diversity
34
28
38
26
29
30
24
31
31
33
28
27
34
27
27
27
25
30
29
24
24
25
27
27
27
27
21
24
25
25
23
26
23
23
Probengewicht
23.70
17.28
16.45
17.17
20.77
21.36
17.99
18.46
20.98
19.72
18.65
19.82
19.87
19.31
20.20
20.00
16.95
18.21
16.70
18.70
19.60
16.89
18.30
20.60
17.45
20.23
18.21
19.40
19.40
18.77
18.90
18.10
17.25
19.83
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
0.0237
0.0173
0.0165
0.0172
0.0208
0.0214
0.0180
0.0185
0.0210
0.0197
0.0187
0.0198
0.0199
0.0193
0.0202
0.0200
0.0170
0.0182
0.0167
0.0187
0.0196
0.0169
0.0183
0.0206
0.0175
0.0202
0.0182
0.0194
0.0194
0.0188
0.0189
0.0181
0.0173
0.0198
Fields of view
34
22
35
27
35
48
28
10
12
13
15
10
30
12
21
15
27
13
15
14
13
13
22
14
23
18
35
25
20
26
22
41
30
42
Surface area [cm2]
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Comment
FO D. lodoensis
CHAPTER IV
Water volume V [ml]
Sphenolithus furcatoides
Rhomboaster cuspis
1260B (mbsf)
δ13C (‰)
1.33
0.66
0.60
0.55
0.61
0.56
0.44
0.32
0.31
0.30
0.47
1.08
0.94
1.00
0.46
0.99
0.59
0.41
0.33
0.45
0.30
0.41
0.23
0.24
0.37
0.63
0.66
0.80
1.13
1.15
1.23
1.44
1.50
1.39
2
X
Size meaasurement
2
2
2
4
2
2
4
1
1
1
3
1
2
1
4
3
4
2
4
1
2
1
3
Toweius callosus
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Toweius eminens
1
1
Toweius pertusus
209
114
112
94
103
79
80
80
92
93
93
188
167
205
139
141
132
92
82
92
108
60
83
86
103
109
109
128
143
190
Toweius serotinus
2
2
7
3
2
3
1
1
3
3
1
1
1
2
2
1
3
1
1
3
14 51
32
45
28
25
37
18
24
25
21
20
27
38
46
39
28
51
34
5 38
4 26
5 28
2 25
2 25
4 32
9 39
4 38
4 38
8 33
19 74
8 66
Coccolithus pelagicus s. str.
9
3
9
5
5
1
4
3
3
1
6
3
14
11
10
6
Coccolithus crucis
X
Coccolithus latus
4
1
19 1
22 2
33 2
29 6
29 11
56 6
66 1
43 5
55 5
38 6
1
7 2
12 4
1 7
9 8
9 1
42 6
36 3
37 4
46 2
47 4
46 1
33 5
36 2
46 4
46 4
23 2
14 1
8 3
Coccolithus minimus
Fig. 4.17c: Nannofossil results 1260B
238,83
238,84
238,85
238,86
238,87
238,88
238,89
238,91
238,92
238,93
239,23
239,58
241,08
241,80
242,05
242,30
242,47
242,48
242,49
242,50
242,51
242,52
242,53
242,54
242,55
242,58
242,59
245,63
251,65
251,87
253,15
253,17
254,65
254.65
256,16
1
1
4
4
7
14
15
18
13
14
26
10
10
2
16
13
19
18
19
18
29
28
27
44
49
45
16
15
15
8
4
7
3
56
75
57
83
60
58
46
69
55
80
40
40
32
42
49
34
35
28
27
39
61
43
42
32
32
32
29
4
3
X
2
1
10
8
7
9
1
4
3
2
3
4
9
13
2
5
1
4
10
12
4
2
4
13
6
10
13
14
5
X
X
1
1
X
1
1
1
1
1
1
2
7
3
7
1
3
10
4
5
6
1
1
2
3
4
3
4
6
2
10
5
7
4
5
5
1
1
4
1
X
6
11
24
25
26
20
26
22
12
20
33
2
26
17
18
28
13
18
26
32
5
11
17
15
25
21
21
25
18
10
Coronocyclus sp.1 (thicker)
3
5
2
1
1
7
1
6
1
1
1
1
1
2
2
3
1
1
2
1
2
4
2
2
3
2
Calcidiscus sp.
X
3
3
2
2
4
1
3
3
Calcidiscus bicircus
1
1
1
2
1
2
2
1
Ellipsolithus spp.
X
Ellipsolithus anaduloensis
X
1
1
1
1
1
1
X
1
2
1
1
1
X
1
1
1
2
X
X
2
Pontosphaera spp.
1
X
1
X
1
1
1
X
X
1
1
X
2
2
X
1
X
X
X
1
1
1
1
1
?1
X
2
1
3
1
X
1
3
4
2
1
1
1
2
1
X
2
1
2
2
1
1
1
2
1
2
Blackites sp. 1
1
X
1
X
1
X
2
X
1
1
1
Blackites sp. 2
X
1
1
1
Blackites stilus
1
Semihololithus sp.1
1
Zygrhablithus sp.
2
5
X
1
X
X
Zygrhablithus bijugatus cornutus
X
X
3
Micrantolithus sp.
X
APPENDIX
99
Syracosphaera ? tanzanensis
Calciosolenia spp.
Jakubowskia leoniae
Chiasmolithus rosenkrantzii
Discoaster spp.
X
1
1
1
1
Discoaster sp. 1
1
1
X
1
X
1
X
4
2
X
2
1
1
1
3
2
3
1
1
Discoaster sp. 2
X
X
X
X
Discoaster sp. 3
2
1
2
3
1
4
4
3
2
1
1
X
2
2
X
2
3
2
4
1
2
1
4
1
1
1
1
1
X
X
X
3
4
4
1
2
X
6
1
3
8
5
2
2
2
2
3
3
X
2
X
X
1
3
1
X
X
4
3
2
Discoaster kuepperi
X
1
1
1
1
2
4
4
1
2
1
1
1
5
4
3
7
3
4
2
5
3
8
1
1260B (mbsf)
Fig. 4.17d: Nannofossil results 1260B
100
238,83
238,84
238,85
238,86
238,87
238,88
238,89
238,91
238,92
238,93
239,23
239,58
241,08
241,80
4 242,05
242,30
242,47
242,48
242,49
242,50
242,51
242,52
242,53
242,54
242,55
242,58
242,59
245,63
251,65
251,87
253,15
253,17
254,65
254.65
256,16
X
X
1
2
1
1
X
X
1
2
X
1
X
X
X
X
X
1
11
1
3
1
1
1
X
4
5
1
1
1
2
2
1
7 10
9 1
11 2
8 2
15 2
10 2
9 1
6
12 1
15
X 7
X 6
7
10
10
2 19
9 15
6 21
11 11
5 15
3 10
2 19
1 15
1 17
1 17
1 17
43
8
1
X
1
3
Rhomboaster cuspis
X
X
4
4
X
3
4
9
2
5
7
3 X
5
1 1
4 2
4 1
8 X
10 2
3 4
8 7
4 8
1 14
7 4
5 1
8 2
5 1
5 1
6
2
6
9
6
7
6
7
9
8
1
4
1
Sphenolithus furcatoides
1
4
1
1
1
Counted individuals
135
156
153
169
158
140
134
147
136
135
89
121
91
120
134
107
142
148
157
128
177
163
157
127
118
119
112
84
42
0
0
27
0
255
0
Simple diversity
19
29
23
26
26
28
24
25
25
25
21
23
24
26
28
26
24
29
28
27
26
29
26
26
22
28
28
26
22
22
Probengewicht
19.40
21.30
19.45
20.60
16.70
20.83
17.95
17.09
20.00
15.91
17.10
19.90
19.99
18.00
20.00
17.00
22.00
19.60
20.10
21.00
20.40
21.80
22.30
21.30
17.70
20.80
18.10
17.30
20.68
19.00
17.14
18.50
16.12
16.30
18.81
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
0.0194
0.0213
0.0195
0.0206
0.0167
0.0208
0.0180
0.0171
0.0200
0.0159
0.0171
0.0199
0.0200
0.0180
0.0200
0.0170
0.0220
0.0196
0.0201
0.0210
0.0204
0.0218
0.0223
0.0213
0.0177
0.0208
0.0181
0.0173
0.0207
0.0190
0.0171
0.0185
0.0161
0.0163
0.0188
Fields of view
16
54
47
49
55
39
50
36
34
42
45
48
33
15
34
21
47
69
43
42
35
51
40
29
27
24
20
35
16
17
Surface area [cm2]
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
ETM2
Comment
NP10
NP10d
FO D. diastypus
T. contortus subzone
of Aubry, 1995
G
NP11 LO T. contortus
NP10d LO T. contortus
NP 11
CHAPTER IV
Water volume V [ml]
CHAPTER V
Chapter V
Calcareous nannofossil response to the
Paleocene-Eocene thermal maximum at DSDP
Site 401 (Bay of Biscay)
101
CHAPTER V
Chapter V: Calcareous nannofossils response to the Paleocene-Eocene thermal
maximum at DSDP Site 401 (Bay of Biscay)
The data of this chapter will be a contribution to a publication by several authors, working on
different calcareous microfossils and geochemical proxies from DSDP Site 401. Results of this
chapter are discussed in chapter VI.
Abstract
Calcareous nannofossils of the Paleocene-Eocene thermal maximum (PETM) have been investigated
from an North Atlantic setting (DSDP Site 401; Bay of Biscay). The PETM consists of a thick
clay-rich sequence with well preserved calcareous nannofossils. Carbon isotopes represent the
typical asymmetric negative δ13C anomaly of ~2 per mil, oxygen isotope data suggest high rates of
freshwater supply into the Bay of Biscay resulting in enhanced water column stratification during
the PETM (Bornemann et al., 2012). Calcareous nannofossil results indicate eutrophic conditions
during the event. The biometry results of Coccolithus pelagicus show - in contrast to our equatorial
study site (chapter II) - no influence on the coccolith size. Typical PETM “excursion taxa” like
Discoaster araneus and Coccolithus bownii are absent.
5.1. Introduction
The late Paleocene - early Eocene greenhouse world is marked by three hyperthermal events (PETM,
ETM2, ETM3) (e.g. Kennett & Stott, 1991; Thomas et al., 2000; Zachos et al., 2001; Cramer
et al., 2003; Lourens et al., 2005; Sexton et al., 2006; Agnini et al., 2009). These hyperthermal
events are characterised by carbon isotope depletion and triggered by orbital forcing (Lourens et
al., 2005, Westerhold et al., 2009). Global warming led to the melting of methane “ice” (Dickens
et al., 1995; Dickens et al., 1997; Dickens, 2000) and to the decomposition of soil organic carbon
in circum-Arctic and Antarctic permafrost (DeConto et al., 2012). The most intense studied
hyperthermal event, the Paleocene-Eocene thermal maximum (PETM) (Kennett & Stott, 1991),
occurred 55.5 million years ago and had an estimated duration of 196ka (Murphy et al., 2010).
It is characterised by a carbon isotope excursion (CIE) of ~-3‰, and 3-4°C warming of surface
water temperatures (Thomas, 1998). The effects of elevated CO2 concentrations (Royer et al.,
2004; Yapp, 2004) and extreme warmth on calcareous nannofossils during hyperthermal events
are in the focus of an ongoing debate (e.g. Jiang & Wise, 2006; Mutterlose et al., 2007; Gibbs
et al., 2010). Non-quantitative observations of size changes in coccoliths and “malformation” in
nannoliths during the PETM were interpreted using the acidification experiments of Riebesell et al.
(2000). While a 0.25 to 0.45-unit decline in surface water pH is possible for the PETM (Ridgwell
& Schmidt, 2010), reconstructed nannoplankton production did not appear to vary significantly
across the PETM, indicating that there is no evidence for interruption of phytoplankton carbonate
production in geological timescales (Gibbs et al., 2010). Latest acidification experiments suggest
a rapid (within ~500 asexual generations = 320 days) adaptive evolution in Emiliania huxleyi to
higher CO2 concentrations (Lohbeck et al., 2012).
102
SECTION AND MATERIAL
Results from size measuring data of Coccolithus pelagicus at our equatorial study site
(Demerara Rise; chapter II & IV) suggest a dwarfing of C. pelagicus and a high abundance of its
small eco-phenotype, also referred to as C. minimus. This chapter provides a calcareous nannofossil
record of the Paleocene-Eocene thermal maximum (PETM) from the North Atlantic, and is thought
to present comparable data to the equatorial Atlantic study site (chapter II).
DSDP Site 401 (Fig. 5.1) is located on a tilted fault block on the northern margin of the Bay of
Biscay (North Atlantic; 44°N paleolatitude) (Tremolada & Bralower, 2004). The interval consists
of nannofossil chalk (Montadert & Roberts, 1979) and spans the calcareous nannofossil zones NP9
to NP11 of Martini (1971). The benthic Foraminifera Extinction Event (BEE), contemporaneous
with the carbon isotope excursion (CIE) onset has been described by Pak & Miller (1992) during
the interval 202.60-202.40mbsf. The paleo water-depth for the PETM is estimated to have been
1800–2000m (Pak & Miller, 1992; Ducasse & Peypouquet, 1979). Calcareous nannofossils have
been studied from 28 settling-slide samples, to gain the total abundances and diversity. Therefore,
a total of 350-400 individuals per sample was counted and the total abundances were determined
following Geisen et al. (1999).
Fig. 5.1.: Paleogeographic reconstruction (55Ma). The sampling location DSDP Site 401 is indicated by a
red star. Other important calcareous nannofossil study sites are indicated as well. The figure is modified from
http://www.odsn.de.
5.3. Calcareous nannofossils and paleoenvironmental changes during the
PETM
The following calcareous nannofossil taxa exclusively appear at DSDP Site 401, they are absent
from the Demerara Rise record of the PETM (chapter 2): Discoaster mediosus, Discoaster
binodosus, Neocoocolithes dubius, Pontosphaera rimosa, Zygrhablithus spp., Zygrhablithus bijugatus,
Cyclicargolithus floridanus, Micrantolithus crenulatus, Hornibrookina arca, Braarudosphaera bigelowii,
Prinsius cf. Prinsius martinii and Neocrepidolithus grandiculus. Delicate calcareous nanofossil taxa
(e.g. Z. bijugatus) and abundant coccospheres, implicate better preservation for this site, compared
to the Demerara Rise record. Some taxa like Discoaster falcatus appear in both locations but are
103
CHAPTER V
more abundant at DSDP Site 401.
With the onset of the PETM the nannofossil diversity increases from 26 taxa at 203.83mbsf
to 36 taxa in 202.86mbsf (Fig. 5.2). The total abundances show rising values spanning the entire
PETM, implicating elevated abundances during the recovery of the CIE compared to the prePETM interval. The Shannon heterogeneity index (Hs) shows high values during the CIE, similar
to the results observed for the ETM2 and ETM3 at Demerara Rise (chapter 4). Toweius eminens
and Toweius serotinus show the same abundance pattern observed in the Chesapeak Bay (Self-Trail
et al., 2012), with a peak of T. eminens in the pre-PETM and a peak of T. serotinus during the CIE.
This pattern is not observed at the Demerara Rise (chapter 2). The different ecophenotypes of
Coccolithus pelagicus (small Coccolithus minimus and Coccolithus latus with a large central opening)
do not show a short-termed higher abundance of C. minimus as observed at Demerara Rise (chapter
4). In some horizons reworked cretaceous taxa appear (e.g. Arkhangelskiella sp. Microrhabdulus sp.
Cyclagelosphaera argoensis, Cretarhabdus sp., Watznaueria barnesiae, Watznaueria sp.).
In contrast to the calcareous nannofossil PETM record at Demerara Rise, no malformed
(or teratoid) discoasters are present at this site. Typical PETM „excursion taxa“, like Discoaster
araneus, which is interpreted by several authors to reflect surface water acidification (e.g. Bybell &
Self-Trail, 1995; Jiang & Wise, 2006; Mutterlose et al., 2007; Raffi & De Bernardi, 2008; Raffi et
al., 2009; Self-Trail et al., 2012) and Coccolithus bownii, representing up to 30% of the nannofossil
assemblage during the PETM at Demerara Rise, are not present at this site. The PETM-specific
taxa Rhomboaster cuspis, Rhomboaster spineus and Rhomboaster bramlettei are present during the CIE
and the recovery interval. The extinction of Fasciculithus shows the same pattern compared to the
equatorial record. Mesotrophic calcareous nannofossil taxa like Campylosphaera and Chiasmolithus
(Mutterlose et al., 2007; Kalb & Bralower, 2012) stay on low abundances during the PETM while
the paleoenvironmental index of Gibbs et al. (2010) in contrast to the Demerara Rise record,
suggests conditions with high productivity during the entire investigated interval. Studies on
ostracods from the DSDP Site 401, showed only minor changes during the PETM, with a temporal
drop in diversity (Yamaguchi & Norris, 2012).
5.4. Size measurements on Coccolithus pelagicus
Size variations in C. pelagicus were investigated in all 28 samples across the PETM. 50 individuals
were measured in each sample. In contrast to the Demerara Rise neither size measurements (Fig.
5.3) nor the frequency plots (Fig. 5.4) indicate a shift to smaller ecophenotypes. In contrast, the
frequency plot indicates a certain shift during the PETM to bigger ecophenotypes. In the pre-PETM
interval and in the uppermost samples the most common observed length is 7μm. During the
PETM “clay layer” the most common observed length rises up to 8μm. The results from the mixture
analysis (Fig. 5.5) suggest two different dominant sizes for the length of C. pelagicus in contrast to
three indicated ecophenotypes from the long-term record at Demerara Rise (chapter4).
104
SIZE MEASUREMENTS ON COCCOLITHUS PELAGICUS
Fig. 5.2. Core photo, calcareous nannofossil features (diversity, total abundance and the paleoenvironmental
index (Gibbs et al., 2010) and individual species abundances. The total abundances of the individual species are
indicated at the bottom of the figure.
The mixture analysis of the length
(central opening) shows similar patterns
compared to the mixture analysis
of the total length, indicating two
ecophenotypes differing in size, but
constant shape (total length / central
opening length ratio).
105
106
Fig.5.3. Mean and median of coccolith length and width as well as the same parameters of the central opening. The figured mean values include the 95% confidence and
the standard deviation. The figured median includes the 10% - 90% percentile and minimum – maximum values.
CHAPTER V
Fig.5.4. Core photograph mean length and width of the length and central opening and the frequency (mode) of length and the length of the central opening across
the PETM.
SIZE MEASUREMENTS ON COCCOLITHUS PELAGICUS
107
CHAPTER V
Fig.5.5. Length vs. width and mixture analysis fro the length and the length of the central opening.
Fig.5.6. 1-4) Toweius pertusus (coccosphere); XN; sample 401 14R 2w 103; scale bar=5µm; 201.03mbsf.
5) Toweius pertusus; XN; sample 401 14R 5w 40; scale bar=5µm; 204.9mbsf. 6) Toweius occultatus; XN;
sample 401 14R 5w 40; scale bar=2µm; 204.9mbsf. 7) Toweius eminens; XN; sample 401 14R 5w 40; scale
bar=5µm; 204.9mbsf. 8) Toweius serotinus; XN; sample 401 14R 3w 101; scale bar=5µm; 202.55mbsf. 9)
Hornibrookina arca; light field; sample 401 14R 3w 86; scale bar=2µm; 202.55mbsf. 10) Hornibrookina
arca; XN; sample 401 14R 3w 86; scale bar=2µm; 202.55mbsf. 11) Cyclicargolithus floridanus; XN; sample
401 14R 3w 136; scale bar=5µm; 202.86mbsf. 12) Cyclicargolithus luminis; XN; sample 401 14R 3w 136;
scale bar=5µm; 202.86mbsf. 13-15) Coccolithus pelagicus (coccosphere); XN; sample 401 14R 3w 62;
scale bar=5µm; 202.12mbsf. 16) Coccolithus pelagicus s.str.; XN; sample 401 13R 5w 88; scale bar=5µm;
195.88mbsf. 17) Coccolithus pelagicus (small); XN; sample 401 14R 3w 62; scale bar=5µm; 202.12mbsf. 18)
Coccolithus latus; XN; sample 401 14R 3w 62; scale bar=5µm; 202.12mbsf. 19) Campylosphaera dela; XN;
sample 401 13R 5w 88; scale bar=5µm; 195.88mbsf. 20) Cruciplacolithus latipons; XN; sample 401 14R 1w
43; scale bar=5µm; 198.93mbsf. 21) Chiasmolithus bidens; XN; sample 401 14R 3w 101; scale bar=5µm;
202.51mbsf. 22) Chiasmolithus consuetus; XN; sample 401 14R 4w 38; scale bar=5µm; 203.38mbsf. 23)
Chiasmolithus nitidus; XN; sample 401 14R 3w 101; scale bar=5µm; 202.51mbsf. 24) Clausicoccus fenestratus;
XN; sample 401 14R 3w 101; scale bar=5µm; 202.51mbsf. 25) Calcidiscus ? bicircus; XN; sample 401 13R
5w 88; scale bar=5µm; 195.88mbsf. 26) Ellipsolithus distichus; XN; sample 401 14R 1w 43; scale bar=5µm;
198.93mbsf. 27) Ellipsolithus distichus; XN; sample 401 14R 3w 101; scale bar=10µm; 202.51mbsf. 28)
Zeugrhabdotus sigmoides; XN; sample 401 14R 3w 101; scale bar=10µm; 202.51mbsf. 29) Pontosphaera
rimosa; XN; sample 401 14R 3w 80; scale bar=5µm; 202.30mbsf. 30) Pontosphaera formosa; XN; sample
401 14R 3w 62; scale bar=5µm; 202.12mbsf. 31) Lopholithus nascens; XN; sample 401 14R 3w 136; scale
bar=5µm; 202.86mbsf. 32) Zygodiscus plectopons; XN; sample 401 14R 3w 62; scale bar=5µm; 202.12mbsf.
33) Neochiastozygus distentus; XN; sample 401 13R 5w 88; scale bar=5µm; 195.88mbsf. 34) Neochiastozygus
rosenkrantzii; XN; sample 401 14R 3w 35; scale bar=5µm; 201.85mbsf. 35) Neochiastozygus sp.; light field;
sample 401 14R 3w 35; scale bar=5µm; 201.85mbsf. 36) Bomolithus sp.; XN; sample 401 14R 3w 20; scale
bar=5µm; 201.70mbsf. 37) Calcidiscus sp.; XN; sample 401 14R 3w 35; scale bar=5µm; 201.85mbsf. 38)
Neococcolithes dubius; XN; sample 401 14R 2w 60; scale bar=5µm; 200.60mbsf. 39) Calciosolenia aperta;
XN; sample 401 14R 3w 101; scale bar=5µm; 202.51mbsf. 40) Syracosphaera sp.; XN; sample 401 14R 3w
136; scale bar=5µm; 202.86mbsf.
108
APPENDIX
Fig. 5.6
109
CHAPTER V
Fig.5.7: 1) Zygrhablithus; XN; sample 401 13R 4w 3; scale bar=5µm; 193.53mbsf. 2) Zygrhablithus bijugatus;
XN; sample 401 14R 3w 86; scale bar=5µm; 202.86mbsf. 3) Zygrhablithus bijugatus; XN; sample 401
14R 3w 35; scale bar=5µm; 201.85mbsf. 4) Zygrhablithus bijugatus; light field; sample 401 14R 3w 35;
scale bar=5µm; 201.85mbsf. 5) Braarudosphaera bigelowii; XN; sample 401 14R 3w 101; scale bar=5µm;
202.51mbsf. 6) aff. Braarudosphaera bigelowii; XN; sample 401 14R 3w 62; scale bar=5µm; 202.12mbsf. 7)
Micrantholithus crenulatus; XN; sample 401 14R 3w 80; scale bar=5µm; 202.30mbsf. 8) Discoaster mediosus;
XN; sample 401 14R 3w 20; scale bar=5µm; 201.70mbsf. 9) Discoaster binodosus; XN; sample 401 14R
3w 47; scale bar=5µm; 201.97 mbsf. 10) Discoaster binodosus; XN; sample 401 14R 3w 86; scale bar=5µm;
202.36mbsf. 12) Discoaster salisburgensis; XN; sample 401 14R 3w 62; scale bar=5µm; 202.12mbsf. 13)
Discoaster sp.; XN; sample 401 14R 3w 35; scale bar=5µm; 201.68mbsf. 13) Discoaster aff. D. mohleri; XN;
sample 401 14R 3w 35; scale bar=5µm; 201.68mbsf. 14) Discoaster pacificus; XN; sample 401 14R 1w 43;
scale bar=5µm; 198.93mbsf. 15) Discoaster sp.; XN; sample 401 14R 2w 35; scale bar=5µm; 200.35mbsf.
16) Discoaster sp., side view; XN; sample 401 14R 3w 38; scale bar=5µm; 201.88mbsf. 17) Bomolithus sp.;
XN; sample 401 14R 3w 20; scale bar=5µm; 201.70mbsf. 18) Fasciculithus sp.; XN; sample 401 14R 5w 40;
scale bar=5µm; 204.9mbsf. 19) Fasciculithus sp.; XN; sample 401 14R 5w 40; scale bar=5µm; 204.9mbsf. 20)
Fasciculithus schaubii; XN; sample 401 14R 4w 38; scale bar=5µm; 203.38mbsf. 21) Fasciculithus richardii;
XN; sample 401 14R 3w 101; scale bar=5µm; 202.51mbsf. 22) Fasciculithus thomasii; XN; sample 401 14R
3w 101; scale bar=5µm; 202.51mbsf. 23) Fasciculithus thomasii; XN; sample 401 14R 3w 62; scale bar=5µm;
202.12mbsf. 24) Fasciculithus fasciculithus; XN; sample 401 14R 3w 136; scale bar=5µm; 202.86mbsf. 25)
Fasciculithus sp.; XN; sample 401 14R 5w 40; scale bar=5µm; 204.9mbsf. 26) Sphenolithus conspicuus; XN;
sample 401 14R 3w 35; scale bar=5µm; 201.85mbsf. 27-28) Rhomboaster cuspis; XN; sample 401 14R 3w 86;
scale bar=5µm; 202.36mbsf. 29-30) Rhomboaster bramlettei ; XN; sample 401 14R 3w 80; scale bar=5µm;
202.30mbsf. 31) Tribrachiatus orthostylus; XN; sample 401 14R 3w 35; scale bar=5µm; 201.85mbsf. - - Reworked Cretaceous taxa: 32) Microrhabdulus ; XN; sample 401 14R 3w 101; scale bar=5µm; 202.51mbsf.
33) Cretarhabdus crenulatus XN; sample 401 14R 3w 86; scale bar=5µm; 202.36mbsf. 34) Arhangelskiella
sp.; XN; sample 401 14R 3w 86; scale bar=5µm; 202.36mbsf. 35) Watznaueria barnesiae; XN; sample 401
14R 3w 86; scale bar=5µm; 202.36mbsf. 36-37) Cyclagelosphaera argoensis; XN; sample 401 14R 3w 47;
scale bar=5µm; 201.97mbsf. 38) Unknown species; XN; sample 14 3 35; scale bar=5µm; 201.85mbsf.
110
APPENDIX
Fig. 5.7
111
mbsf
3
5
2
1
1
2
2
1
3
5
2
5
2
1
2
1
3
3
1
1
2
4
4
6
7
3
8
4
6
6
8
10
12
20
17
1
8
3
5
4
3
8
6
7
4
Toweius callosus
3
1
Toweius serotinus
Toweius pertusus
Toweius occultatus
125 5
1 125 14
4 104 2
2 148 4
179 14
4 152 5
2 205 11
220 17
189 10
5 206 19
202 11
1 223 12
4 238 13
1 241 9
3 222 13
5 160 17
2 187 18
5 190 21
7 185 25
5 203 25
7 172 21
195 22
5 221 17
3 173 26
4 180 9
124 9
4 97 7
5 90 11
X
5
3
2
X
X
3
2
1
2
X
X
1
1
5
3
1
4
6
5
X
X
X
X
5
4
Coccolithus pelagicus (s. str.)
Cyclicargolithus floridanus
100 8
1 110 2
2 136 9
1 110 8
3 84 6
4 87 8
3 48 7
50 7
33 7
3 51 13
5 75 5
42 10
X 57 4
40 5
61 4
97 5
79
63 8
67 11
69 9
65 13
69 16
77 10
69 8
102 3
115 21
86 4
155 4
Coccolithus latus
11
5
9
9
5
16
9
4
11
15
10
7
6
10
7
2
5
4
4
3
5
8
23
15
18
6
5
9
Coccolithus minimus
1
1
4
7
8
3
3
6
24
18
4
8
3
1
6
3
10
7
6
3
9
7
X
5
6
4
2
10
X
X
X
X
3
10
1
7
5
7
12
12
10
7
8
5
X
1
7
1
1
5
7
12
2
2
5
2
3
4
1
1
X
4
1
2
3
3
5
2
1
2
3
X
13
15
10
5
10
1
4
1
3
8
1
1
1
2
1
2
2
3
1
2
1
2
Cruciplacolithus lapitons
1
X
X
X
1
1
1
X
1
3
X
2
5
2
4
1
2
X
1
X
3
X
1
1
4
5
1
1
1
1
X
X
2
X
X
2
X
1
X
1
2
X
1
1
X
X
X
2
2
X
X
1
1
3
X
2
8
1
2
1
1
1
2
2
2
X
1
X
2
X
1
X
2
X
X
1
X
1
X
19
15
10
7
14
3
3
2
11
12
10
1
7
3
9
9
7
3
1
1
X
X
6
Ellipsolithus spp.
1
1
X
3
X
X
X
X
1
2
X
X
1
2
X
X
X
1
4
1
1
X
X
X
Fig.5.8a. Calcareous nannofossil results from the Bay of Biscay, DSDP Site 401
204.9
204.1
203.38
202.86
202.51
202.36
202.30
202.12
201.97
201.88
201.85
201.70
201.55
201.03
200.60
200.35
199.65
199.10
198.93
198.90
195.88
195.45
195.05
194.80
194.43
193.93
193.53
Toweius eminens
112
193.30
X
X
2
X
1
1
X
1
X
1
1
X
2
Helicosphaera sp.
X
Pontosphaera sp.
X
X
1
1
X
2
X
2
X
1
1
X
X
1
2
Pontosphaera rimosa
X
X
X
X
X
1
X
3
1
1
2
1
X
X
1
1
1
2
4
1
1
X
1
1
1
X
2
X
4
2
1
X
1
X
2
1
1
1
3
4
X
1
2
4
2
2
1
X
1
X
1
X
X
X
1
1
X
1
1
1
1
2
X
1
4
1
7
1
2
3
4
5
1
2
7
3
X
1
X
1
1
2
1
3
4
X
1
X
2
1
X
6
1
1
X
1
1
1
1
X
X
Neococcolithes dubius
X
X
X
X
X
X
X
X
X
X
X
1
1
1
1
Zygrhablithus spp.
1
1
2
4
5
18
16
9
4
14
Zyghrablithus bijugatus
15
8
4
2
1
3
4
8
7
10
9
8
22
14
12
8
X
X
5
8
5
2
13
2
Micrantholithus crenulatus
X
X
Discoaster spp.
1
1
3
X
2
4
1
2
1
2
X
1
4
1
1
1
2
4
5
2
4
1
4
10
6
7
4
4
2
12
12
2
X
3
2
5
11
1
3
1
X
1
1
1
1
4
2
1
2
X
1
1
1
1
X
1
4
1
1
X
Discoaster aff. D. nobilis
2
1
1
1
1
1
1
1
X
Discoaster mediosus
X
1
1
1
1
1
2
1
X
1
1
1
X
X
1
2
Discoaster falcatus
2
1
X
1
1
X
X
1
1
X
Discoaster binodosus
X
X
X
X
3
2
1
1
1
1
1
1
1
1?
1
2
X
3
1
2
1
CHAPTER V
mbsf
Fasciculithus spp.
1
3
4
2
2
9
8
23
35
16
1
1
1
4
1
1
6
2
2
1
2
1
1
1
1
3
6
4
6
1
1
1
1
1
1
3
1
4
Fasciculithus richardii
1
Bomolithus sp.
1
Bomolithus aquilus
1
Rhomboaster spineus
2
X
X
Rhomboaster cuspis
1
X
X
X
2
X
2
X
1
X
1
X
X
X
16
13
13
16
12
15
6
5
2
7
3
7
8
3
4
9
7
4
4
1
6
5
8
2
4
11
8
1
Hornibrookina arca
1
X
1
1
3
3
1
1
1
X
1
2
X
X
Prinsius martinii
4
Zeugrhabdotus sigmoides
Watznaueria barnesiae
Cretarhabdus sp.
Cyclagelosphaera argoensis
Microrhabdulus sp.
Arkhangelskiella sp.
X
X
1
X
1
1
X
X
4
X
X
X
1
2
X
X
1
5
5
1
reworked Cretaceous taxa
1
Watznaueria sp.
Fig.5.8b. Calcareous nannofossil results from the Bay of Biscay, DSDP Site 401
204.9
204.1
203.38
202.86
202.51
202.36
202.30
202.12
201.97
201.88
201.85
201.55
201.03
1
1
201.70 5
200.60
199.65
1
200.35 3
199.10
198.93
198.90
195.88
194.80
194.43
3
1
195.05 5
195.45 3
193.93
193.53
193.30
Counted individuals
343
324
338
338
375
356
337
354
326
390
350
323
358
340
373
335
366
349
353
385
350
366
422
361
376
344
305
372
Diversity (species richness)
24
29
29
31
35
35
32
23
22
34
35
29
33
27
29
33
34
34
29
34
36
35
34
35
33
28
24
33
Shannon diversity (HS)
2,091
1,917
2,017
1,93
2,068
2,183
1,79
1,563
1,742
2,034
1,741
1,459
1,545
1,393
1,705
1,851
1,908
1,915
1,854
1,862
2,065
1,912
1,91
2,039
1,882
1,973
2,15
2,103
Probengewicht [mg]
15.37
15.62
17.05
18.91
16.15
17.54
15.84
15.75
15.2
17.65
17.5
13.3
15.3
14.8
15.22
14.89
15.3
14.05
15.14
15.55
13.07
18.94
15.03
15.78
21
15.15
15.24
16.23
Water volume [ml]
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
Mass of sediment [g]
0.01537
0.01562
0.01705
0.01891
0.01615
0.01754
0.01584
0.01575
0.0152
0.01765
0.0175
0.0133
0.0153
0.0148
0.01522
0.01489
0.0153
0.01405
0.01514
0.01555
0.01307
0.01894
0.01503
0.01578
0.021
0.01515
0.01524
0.01623
number of fields of view
14
17
14
11
14
10
8
13
10
10
12
7
12
7
8
11
16
11
11
10
17
10
10
27
10
15
49
21
Surface area [cm2]
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
0.000141
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2,826,266,513
2,163,395,666
2,510,644,240
2,881,067,161
2,940,705,958
3,598,664,047
4,715,259,868
3,065,492,427
3,802,724,897
3,917,786,752
2,955,082,742
6,151,396,729
3,457,253,666
5,818,888,798
5,431,566,341
3,626,421,828
2,650,883,048
4,003,845,527
3,758,175,362
4,389,865,682
2,792,958,170
3,426,273,338
4,978,223,223
1,502,302,310
3,174,603,175
2,683,956,339
724,168,597
1,935,200,740
Intervals
Pre-PERM
CIE
Recovery
Post-PETM
NP Zones (Martini?=
Base NP9b
Top NP9a FO R. bramlettei
Base NP10 FO D.diastypus
APPENDIX
113
CHAPTER V
114
CHAPTER VI
Chapter VI
General conclusions and perspective
115
CHAPTER VI
Chapter 6: General conclusions and perspective
The Paleocene-Eocene thermal maximum (PETM) is the most prominent deep-time ocean
acidification event in earth history known so far. It therefore is an analog to the ongoing recent
ocean acidification caused by fossil fuel burning. This study has been performed on a total of 328
settling slides (167 samples from the PETM of Demerara Rise, 133 samples spanning the ETM2
and ETM3 at Demerara Rise and 28 samples across the PETM from the Bay of Biscay, DSDP Site
401). A total of 70 samples across the PETM at Demerara Rise where used for a geochemical study
(XRF). Size measurement data of Coccolithus pelagicus were collected from 170 samples across the
late Paleocene to early Eocene, resulting in 34,000 data points.
6.1. Ocean acidification and climate
The PETM is interpreted as the result of a long-term gradual warming trend, triggering the release
of carbon to the oceans and the atmosphere (e.g. Dickens, 1994, 1995, 2003, 2011; DeConto et
al., 2012). Due to a general shoaling of the carbonate compensation depth (e.g. Zachos, 2005),
extreme warming (e.g. Zachos et al., 2003; Tripati & Elderfield, 2004; Sluijs et al., 2006) and the
description of “malformed” calcareous nannofossils, the PETM has attracted a lot of attention in the
research community. The malformation has been interpreted as result of surface water acidification
(e.g. Bybell & Self-Trail, 1995; Jiang & Wise, 2006; Mutterlose et al., 2007; Raffi & De Bernardi,
2008; Raffi et al., 2009; Self-Trail et al., 2012). The carbon input during the PETM, however, had
only a moderate impact on the surface-water saturation state (Gibbs et al., 2006; Zeebe et al., 2009;
Gibbs et al., 2010; Ridgwell & Schmidt, 2010). Direct effects of ocean acidification on surface
calcifiers during the PETM may have been limited because of a relatively slow carbon input rate
(Zeebe, 2012). Sr/Ca reconstructions for the PETM suggest undisturbed carbonate production
during the PETM (Stoll et al., 2007, Gibbs et al., 2010). Lithological and paleontological records
from a Paleogene carbonate platform in the Pacific Ocean also show no major evidence for a
carbonate production crisis (Robinson, 2010). For the PETM excursion species Discoaster araneus
it has been pointed out that it is most likely not a teratoid (=malformed) form because it lacks a
concrete ancestral parent taxon, and is, due to its longevity, abundance and distribution, quiet
successful (Bown & Pearson, 2009). Furthermore, discoasters are nannoliths, not coccoliths and
thought to be formed by haptophytes, but probably by a different biomineralisation process to
either heterococcoliths or holococcoliths (Young et al., 1999). Our results show that discoasters
with unusual symmetry are not limited to the carbon isotope excursions, and therefore increased
surface water acidification can be excluded to cause this phenomenon (chapter IV). SEM pictures
do not show evidence for disrupted calcification in Coccolithus during the PETM (Fig. 6.1).
Fig. 6.1. 1) Discoaster multiradiatus 2) Discoaster sp. 3) Coccolithus pelagicus 4) C. pelagicus, 5) Discoaster sp.
6) Discoaster spp. 7) Coroncyclus bramlettei 8) C. pelagicus 9) Discoaster sp. 10) Toweius serotinus, 11) Toweius
pertusus 12) C. pelagicus, 13) Discoaster araneus, 14) D. araneus, 15) D. araneus, 16) Rhomboaster bramlettei,
17) Thoracosphaera operculata 18) Discoaster cf. D. mohleri 19) D. multiradiatus 20) D. multiradiatus (side
view) 21) C. pelagicus, 22) C. pelagicus 23) Unidentified species 24) C. pelagicus, 25) C. pelagicus.
116
OCEAN ACIDIFICATION AND CLIMATE
Fig. 6.1
117
CHAPTER VI
The speed of warming provides evidence for high climate sensitivity to atmospheric CO2
(Pagani et al., 2006b). During the PETM the global temperature increased by more than 5°C in less
than 10,000 years (Zachos et al., 2008). Sea surface temperatures near the North Pole increased by
5°C during the PETM (Sluijs et al., 2006). In the equatorial Pacific seas surface temperatures rose by
4°C to 5°C (Zachos et al., 2003), thermocline temperatures warmed by 3°C (Tripati & Elderfield,
2004). Bottom waters in the equatorial Pacific warmed by 4°C to 5°C, intermediate waters warmed
before the CIE (Tripati & Elderfield, 2005). Southwest Pacific sea surface temperatures increased
from ~26°C to ~28°C (Hollis et al., 2012) / ~33°C (Sluijs et al., 2011) during the PETM.
During the PETM large-sclae changes of intermediate and deep-sea circulation occurred
(Thomas, 2004; Nunes & Norris, 2006; Thomas et al., 2008). This shift in ocean circulation
delivered warmer waters to the deep sea (Bice & Marotzke, 2002). These oceanic changes caused the
benthic Foraminifera extinction event, while oceanic plankton was largely unaffected, suggesting
a decoupling of deep and shallow ecosystems (Kennett & Stott, 1991). Enhanced stratification
during the PETM was caused by thermal stratification (Bralower et al., 2007; Petrizzo, 2007) and
in coastal areas by high rates of freshwater supply due to higher continental runoff (e.g. Crouch et
al., 2003; Bowen et al., 2004; Kelly et al., 2005; Schulte et al., 2011). Reduced deep-water oxygen
levels for the PETM are reported from multiple sites (Chun et al., 2010; Nicolo et al., 2010; Schulte
et al., 2011), while we could find no evidence for dysoxic conditions at the Equatorial Atlantic
(chapter III). Large-scaled fluctuations of the CCD during the Eocene are explained by changes in
weathering and the mode of organic-carbon delivery (Pälike et al., 2012). A marine transgression
during the PETM and approximately 20-30m higher sea-levels are related to changes in seafloor
spreading rate, volcanism, regional perturbation and thermal expansion of the water (Schmitz &
Pujalte, 2003; MacIennan & Jones, 2006; Sluijs et al., 2008b; Handley et al., 2011).
6.2. Evolution
Some of the ecological changes preceding the carbon isotope excursion are reflected by calcareous
nannofossils (chapter II) and by some geochemical results (chapter III). The calcareous nannofossil
record of the early stage of the PETM is obscured by the shoaling of the carbonate compensation
depth. Geochemical productivity proxies (opaline, Ba/Al, P/Al) indicate, however, a massive shorttermed breakdown of the phytoplankton community for this interval (chapter III). But which of
the various environmental factors (e.g. temperature, nutrient availability, oxygen content, pH or
calcite saturation ΩC) is the reason for size-changes in haptophytes?
A high resolution record of continental climate and equid body size change shows a directional
size decrease of ~30% over the first ~130,000 years of the PETM, followed by a ~76% increase in
the recovery phase of the PETM (Secord et al., 2012). Dwarfism of ostracodes during the PETM
interval suggests that their food consumption rates, and lifetimes, were less than those of ostracodes
in the pre-PETM interval (Yamaguchi et al., 2012). The interpretation is based upon previous
studies showing that food consumption and ostracode lifetimes both decrease as ostracodes increase
their growth rates under higher temperatures (Yamaguchi et al., 2012). While changing ocean pH is
118
EVOLUTION
known to have a physiological affect on calcification of recent crustacean exoskeletons (Greenaway,
1985; Simkiss & Taylor, 1989), there is no correlation between size and pH in experiments on living
ostracods (Wansard, 1998; Palacios-Fest & Dettmann, 2001). Taxonomic richness of invertebrates
increases with increasing temperature during the Phanerozoic (Mayhew et al., 2012).
Size changes towards smaller individuals in foraminifera during the PETM are interpreted as
the result of elevated temperatures, causing elevated metabolic rates and food requirements (Alegret
et al., 2010). With deep-water temperatures elevated by 10°C, metabolic rates of foraminifers
increase by a factor of two (e.g. Hallock et al., 1991; Gillooly et al., 2001), and therefore require
twice as much food to keep the same faunal structure (Thomas, 2007). Insufficient food supply
causes a larger number of small sized foraminifers (Corliss et al., 1979; Boltovskoy et al., 1991).
The paleoenvironmental index (PI) of Gibbs et al. (2010) indicates warm oligotrophic
conditions for the PETM at Demerara Rise (equatorial Atlantic, 0° paleolatitude), implying 1)
an enhanced stratification, 2) a reduced equatorial upwelling in the Atlantic (=decreased winds).
In contrast, the PI index across the PETM section at the Bay of Biscay (North Atlantic, ~44°N
paleolatitude) (chapter IV) indicates stable temperatures and high productivity for the investigated
section. The elevated productivity during the PETM at this site, due to higher continental runoff
(Bornemann et al., 2012) is here interpreted to overshadow the temperature signal in the PI index,
because global temperatures generally rose by ~4°C (e.g. Zachos et al., 2003; Tripati & Elderfield,
2004; Tripati & Elderfield, 2005; Sluijs et al., 2006; Zachos et al., 2008; Sluijs et al., 2011; Hollis et
al., 2012). Typical excursion taxa like Coccolithus bownii, D. araneus and malformed discoasters are
absent in the Bay of Biscay, possibly indicating unfavorable (more eutrophic) conditions. Following
the argumentation applied for the dwarfing in foraminifera of Alegret et al. (2010), elevated
nutrient levels would explain the lack of dwarfing in C. pelagicus during the PETM at DSDP
Site 401 (Fig. 6.2), compared to the abundant small sized C. pelagicus, indicating oligotrophic
conditions at Demerara Rise. Increased temperatures lead to accelerated metabolic activity and
growth rate of phytoplankton is generally positively correlated with temperature within a suitable
range (Lund, 1949; Talling, 1955; Eppley, 1979). There is growing evidence that some haptophytes
are not purely photoautotrophic, but additionally grazing on bacteria and small algae (Kawachi
et al., 1991; Jones et al., 1993). This mixotrophic mode of nutrition has been observed only in
species bearing an emergent haptonema, like Coccolithus amongst other taxa (Jordan, 2012). Global
productivity gradients are also described by Gibbs et al. (2006a), indicating decreased open-ocean
productivity and increased nutrient availability in shelf areas. This besides the arguments discussed
in (chapter II & IV), implicates a minor sensitivity of calcareous nannofossils to ocean acidification
during the PETM, which is in accordance to recent studies on extant coccoliths (e.g. Lohbeck et al.,
2012; Smith et al., 2012) and latest PETM studies (e.g. Winguth et al., 2012).
119
CHAPTER VI
Fig.6.2: Compared morphology of C. pelagicus durng the PETM from Demerara Rise (left) (also see chapter
IV) and Bay of Biscay (right) (compare to chapter V).
The long-term evolutionary size trend of C. pelagicus spanning all three hyperthermals
(PETM, ETM2, ETM3) shows a general increase of size during the investigated interval, interrupted
by several short-term events (hyperthermals) with smaller sizes (Fig. 6.3). Generally the size /
morphology of C. pelagicus in the early Eocene is closely related to elevated temperatures during the
hyperthermal events (chapter IV), which are ultimately orbital triggered (e.g. Cramer et al., 2003;
Lourens et al., 2005; Nicolo et al., 2007).
6.3. Perspective
Future CO2 scenarios are more extreme than the PETM and the speed of carbon release may be a
lot faster (Zeebe, 2012). The international political goal, stated in Article 2 of the UN Framework
Convention on Climate Change is to “avoid dangerous anthropogenic interference with the climate
system”. While political goals recently focused on the limitation of global warming to 2°C for 2100
by the Copenhagen Accord (United Nations Conference of the Parties, 2009), growing emissions
of greenhouse gases continue to increase the magnitude of climate change (Meehl et al., 2007).
If atmospheric carbon dioxide concentrations will increase from current levels to a peak of 450600ppmv over the coming century, irreversible dry-season rainfall reductions in several regions will
be the consequence (Solomon et al., 2009). Results from mitigation analyses suggest that a greater
focus on midcentury targets could facilitate the development of policies that preserv potentially
desirable long-term options (O’Neill et al., 2010). The sensitivity of phytoplankton to specific
ecological factors (pH, temperature, nutrients) is still poorly understood. Results from acidification
experiments show species-specific differences in the decreasing cell growth rate of E. huxley and C.
braarudii of 20% (Müller et al., 2010). Modern ocean observations and laboratory experiments
consider timescales that are too short to reveal the long-term potential of marine organisms to
acclimatise or adapt to changing environmental conditions (Hönisch et al., 2010). Experiments
focus on a few species or isolated strains and provide little information on the potential for whole
ecosystem changes (Hönisch et al., 2010). Simulations show higher rates of environmental change
120
PERSPECTIVE
Fig. 6.3.: Cenozoic record of benthic carbon isotope values (Zachos et al., 2008) and the δ13Cbulk, carbonate
and long-term Coccolithus pelagicus biometry record in (µm2) from chapter IV including the PETM, ETM2
and ETM3.
at the surface for the future than the Paleocene-Eocene thermal maximum, which could potentially
challenge the ability of plankton to adept (Ridgwell & Schmidt, 2010). On the other hand
warming of the upper ocean may stimulate plankton metabolism (Behrenfeld, 2011). The global
phytoplankton productivity already declined over the last century, perhaps as a result of increasing
surface-water temperatures (Boyce et al., 2010). Increased average warming of the surface-ocean water
(Levitus et al., 2000; Lyman et al., 2010) is interpreted as the result of anthropogenic greenhouse
gases (Levitus et al., 2001; Barnett et al., 2005). Phytoplankton plays a key role in the cycling
of CO2 from the atmosphere to the biosphere and back and this cycling helps to control earth’s
climate (Falkowski, 2012). Ultimately, the microorganisms in the ocean will survive, as they have
for billions of years, and they will help restore Earth to a biogeochemical steady state (Falkowski,
2012). A “geologically short-termed” decline in oceanic productivity (chapter III) would, however,
have major implications for ecosystems on “normal” timescales recorded in human history. Two
recent studies on foraminifera reported shell thinning, possibly related to modern pH changes
(de Moel et al., 2009; Moy et al., 2009). Data from species distribution models predict range
expansions for foraminifera within the next 40 years and an increased role of larger foraminifera as
121
CHAPTER VI
carbonate producers and reef framework builders (Weinmann et al., 2012). Results from speciesdistribution models corroborate reports that show a remarkable increase and range expansion of
tropical foraminifer species, indicating a continued meridionalization of the Mediterranean Sea
(Langer et al., 2012). Ecological responses to the ongoing climate change include strong shifts in
species phenology, range distributions (Parmesan & Yohe, 2003; Root et al., 2003; Perry et al.,
2005; Chen et al., 2011) and ecological responses (Walther et al., 2002; Parmesan, 2006). Data
analysis of available experimental assessments showed differences in specific organism responses to
elevated pCO2 and propose that marine biota may be more resistant to ocean acidification than
previously expected (Hendriks et al., 2010). General conclusions about the role of evolutionary
adaptation caused by climate change induced fitness loss of wild populations are still difficult to
make (Gienapp et al., 2008; Merilä, 2012). Besides ecological changes, climate change includes
a broad range of potentially hazardous geological and geomorphological activities. These include
submarine and subaerial landslides, tsunamis, glacial outburst, debris flows and gas-hydrate
destabilisation (McGuire, 2010). Organisms producing aragonitic skeletons (e.g. corals) are more
affected by ocean acidification than organisms producing calcitic skeletons. De’ath et al. (2009)
reported a decline in calcification on the Great Barrier Reef by 14.2% between 1990 and 2009.
For the late Paleocene – early Eocene studies on biometry of nannofossils are still rare, except
the study on D. multiradiatus of Tremolada et al. (2008). The taxonomy in publications preceding
the nannofossil record of Bown (2005) generally has to be seen critically. Morphometric studies
of Coccolithus form different ODP sites would be extremely useful, due to its high abundances
and good fossil record. Prominent PETM discoaster excursion taxa, like D. araneus or Discoaster
falcatus could have a potential for SEM-based morphometric studies assessing their individual
calcification budged and morphometric evolution, as we found a variability in the number of
rays during the PETM (chapter II) and no plausible explanation for their evolutionary origin is
known so far. Additionally, geochemical studies assessing plankton productivity during the PETM
(chapter III) would provide an interesting addition to calcareous nannofossil study sites from deepsea environments, where the onset of the PETM is obscured by deep-water dissolution due to the
shallowed CCD.
122
TAXONOMICAL INDEX
Taxonomical index
Arkhangelskiella Vekshina 1959
Biantolithus Bramlette & Martini, 1964
Biantolithus flosculus Bown, 2005
Biantolithus sparsus Bramlette & Martini, 1964
Blackites Hay & Towe, 1962
Blackites ? stilus Bown, 2005
Bomolithus Roth, 1973
Bomolithus aquilus Bown, 2010
Bomolithus/Discoaster megastypus Bramlette & Sullivan, 1961
Braarudosphaera Deflandre, 1974
Braarudosphaera bigelowii (Gran & Braarud, 1935) Deflandre1947
Calcidiscus Kamptner, 1950
Calcidiscus bicircus Bown, 2005
Calciosolenia Gran, 1912 emend. Young et al., 2003
Calciosolenia aperta (Hay & Mohler, 1967) Bown, 2005
Campylosphaera Kamptner, 1963
Campylosphaera eodela Bukry & Percival, 1971
C. dela (Bramlette & Sullivan, 1961) Hay & Mohler, 1967
C. differta Bown, 2010
Chiasmolithus Hay et al., 1966
Chiasmolithus bidens (Bramlette & Sullivan, 1961) Hay & Mohler, 1967
C. consuetus (Bramlette & Sullivan, 1961) Hay & Mohler, 1967
C. nitidus Perch-Nielsen, 1971
C. solitus (Bramlette & Sullivan, 1961) Locker, 1968
Clausicoccus Prins, 1979
Clausicoccus fenestratus (Deflandre & Fert, 1954) Prins, 1979
C. subdistichus (Roth & Hay in Hay et al., 1967) Prins, 1979
Coccolithus Schwartz, 1894
Coccolithus bownii Bown & Pearson, 2009
C. crucis Bown, 2005
C. foraminis Bown, 2005
C. latus Bown, 2005
C. minimus Bown, 2005
C. pelagicus (Wallich, 1877) Schiller, 1930
Coronocyclus Hay et al., 1966
123
TAXONOMICAL INDEX
Coronocyclus bramlettei (Hay & Towe, 1962)
Cretarhabdus Bramlette & Martini 1964
Cruciplacolithus Hay & Mohler in Hay et al., 1967
Cruciplacolithus asymmetricus van Heck & Prins, 1987
C. cassus Bown, 2005
Cruciplacolithus c.f. C. cruciformis (Hay & Towe, 1962) Roth, 1970
C. asymmetricus van Heck & Prins, 1987
C. edwardsii Romein, 1979
C. latipons Romein, 1979
C. primus Perch-Nielsen, 1977 Cyclagelosphaera Noël, 1965
Cyclagelosphaera argoensis Bown, 1992
Cyclicargolithus Bukry 1971
Cyclicargolithus luminis (Sullivan, 1965) Bukry, 1971
Cyclicargolithus c.f. C. floridanus (Roth and Hay in Hay et al., 1967) Bukry 1971
Discoaster Tan, 1927
Discoaster anartios Bybell & Self-Trail, 1995
D. araneus Bukry, 1971
D. barbadiensis Tan, 1927
D. binodosus Martini, 1958
D. delicatus Bramlette & Sullivan, 1961
D. diastypus Bramlette & Sullivan, 1961
D. falcatus Bramlette & Sullivan, 1961
D. kuepperi Stradner, 1959
D. lenticularis Bramlette & Sullivan, 1961
D. lodoensis Bramlette & Riedel 1954
D. mahmoudii Perch-Nielsen, 1981
D. mediosus Bramlette & Sullivan, 1961
Discoaster aff. D. mohleri Bramlette & Percival, 1971
D. multiradiatus Bramlette & Riedel, 1954
Discoaster aff. D. nobilis Martini, 1961
D. pacificus Haq, 1969
D. salisburgensis Stradner, 1961
Ellipsolithus Sullivan, 1964
Ellipsolithus anadoluensis Varol, 1989
124
E. bollii Perch-Nielsen, 1977
TAXONOMICAL INDEX
E. distichus (Bramlette & Sullivan, 1961) Sullivan, 1964
E. macellus (Bramlette & Sullivan, 1964) Sullivan, 1964
Ericsonia Black, 1964
Ericsonia staerkeri Bown, 2005
E. subpertusa Hay & Mohler, 1967
E. robusta (Bramlette & Sullivan, 1961) Edwards & Perch-Nielsen, 1975
Fasciculithus Bramlette & Sullivan, 1961
Fasciculithus alanii Perch-Nielsen, 1971
F. billii Perch-Nielsen, 1971
F. clinatus Bukry, 1971
F. hayii Haq, 1971
F. involutus Bramlette & Sullivan, 1961
F. lillianae Perch-Nielsen, 1971
F. schaubii Hay & Mohler, 1967
F. thomasii Perch-Nielsen, 1971
F. tympaniformis Hay & Mohler, 1967 in Hay et al., 1967
Helicosphaera Kamptner, 1954
Helicosphaera bramlettei (Müller, 1970) Jafar & Martini, 1975
Holodiscolithus Roth, 1970
Holodiscolithus solidus (Deflandre in Deflandre & Fert, 1954) Roth, 1970
Hornibrookina Edwards, 1973
Hornibrookina arca Bybell & Self-Trail, 1995
Jakubowskia leoniae Varol, 1989
Lophodolithus Deflandre in Deflandre & Fert, 1954
Lophodolithus nascens Bramlette & Sullivan, 1961
Lophodolithus aff. Lophodolithus rotundus Bukry & Percival, 1971
Micrantholithus Deflandre in Deflandre & Fert, 1954
Micrantholithus attenuatus Bramlette & Sullivan, 1961
M. crenulatus Bramlette & Sullivan, 1961
Microrhabdulus Deflandre 1959
Neochiastozygus Perch-Nielsen, 1971
Neochiastozygus distentus (Bramlette & Sullivan, 1961) Perch-Nielsen, 1971
N. junctus (Bramlette & Sullivan, 1961) Perch-Nielsen, 1971
N. perfectus (Bramlette & Sullivan, 1961) Black, 1967
N. rosenkrantzii (Perch-Nielsen, 1971) Varol, 1989
N. substrictus Bown, 2005
125
TAXONOMICAL INDEX
Neococcolithes Sujkowski, 1931
Neococcolithes dubius (Deflandre in Deflandre & Fert, 1954) Black 1967
N. protenus (Bramlette & Sullivan, 1961) Black, 1967
Neocrepidolithus Romein, 1979
Octolithus Romein 1979
Pedinocyclus Bukry & Bramlette, 1971
Pedinocyclus larvalis (Bukry & Bramlette 1969) Loeblich & Tappan 1973
Pontosphaera Lohmann, 1902
Pontosphaera formosa (Bukry & Bramlette 1968) Romein, 1979
P. pulchra (Deflandre in Deflandre & Fert, 1954) Romein 1979
P. punctosa (Bramlette & Sullivan, 1961) Perch-Nielsen, 1984
P. rimosa (Bramlette & Sullivan, 1961) Roth & Thierstein, 1972
Prinsius Hay & Mohler, 1967
Prinsius ? martinii (Perch-Nielsen, 1969) Haq, 1971
Rhomboaster Bramlette & Sullivan, 1961
Rhomboaster bramlettei (Brönnimann & Stradner, 1960) Bybell & Self-Trail, 1995
R. cuspis Bramlette & Sullivan, 1961
R. spineus (Shafik & Stradner, 1971) Perch-Nielsen, 1984; plate 1, Fig. 28
Semihololithus Perch-Nielsen, 1971
Sphenolithus Deflandre & Grassé
Sphenolithus acervus Bown, 2005
S. anarrhopus Bukry & Bramlette, 1969
S. arthurii Bown, 2005
S. conspicuus Martini, 1976
S. distentus (Martini, 1965) Bramlette& Wilcoxon, 1967
S. moriformis (Brönnimann & Stradner, 1960) Bramlette & Wilcoxon, 1967
S. radians Deflandre in Grassé, 1952
Syracosphaera ? tanzanensis Bown, 2005
Thoracosphaera Kamptner, 1927
Thoracosphaera operculata Monechi et al., 2000
Toweius Hay & Mohler, 1967
Toweius callosus Perch-Nielsen, 1971
T. eminens (Bramlette & Sullivan, 1961) Perch-Nielsen, 1971
T. occultatus (Locker, 1967) Perch-Nielsen, 1971
126
T. pertusus (Sullivan, 1965) Romein, 1979
TAXONOMICAL INDEX
T. serotinus Bybell & Self-Trail, 1995
Toweius sp.1 Bown, 2005
Toweius sp.2 Bown, 2005
Tribrachiatus Shamrai, 1963
Tribrachiatus contortus (Stradner, 1958) Bukry 1972
T. digitalis Aubry, 1996
T. orthostylus Shamrai, 1963
Umbilicosphaera Lohmann, 1902
Umbilicosphaera ? jordanii Bown, 2005
Watznaueria Reinhardt, 1964
Watznaueria barnesae (Black, 1959) Perch-Nielsen, 1968
Zygodiscus Bramlette & Sullivan, 1961
Zygodiscus plectopons Bramlette & Sullivan, 1961
Zygrhablithus Deflandre, 1959
Zygrhablithus bijugatus (Deflandre in Deflandre & Fert, 1954) Deflandre, 1959
Zygrhablithus bijugatus cornutus (Deflandre in Deflandre & Fert, 1954) Deflandre, 1959;
cornutus Bown, 2005
127
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147
CURRICULUM VITAE
Curriculum Vitae
Christian Joachim, Dipl. Geol.
Nationality: German
Education:
06.2011 - 06.2011 Workshop “project management”, Ruhr-Universität Bochum
10.2002 - 09.2009 Diplom (=degree) in Geology, Rheinische Friedrich-Wilhelms-Universität
Bonn, Germany
07.2009 - 08.2009 USSP, Urbino Summer School in Paleoclimatology
06.2009 - 07.2009 MICOD, Urbino Summer School in Paleoclimatology
01.2009 - 02.2009 Ostracod Analysis - ECRC Short Course, University College London
03.2007 - 04.2007 Applied Micropaleontology - A Short Course, University of Bonn
06.1998 - 06.2001 University entrance qualifications, Märkisches Gymnasium Hamm
Positions:
06.2012 - 07.2012 Visiting scientist, National Oceanography Centre, Southampton, GB
07.2008 - 08.2009 Summer student, Statoil / Hydro in Sandsli Bergen, Norway
10.2005 - 08.2009 Tutor, University of Bonn, Germany
03.2005 - 03.2005 Intern, Deutsche Steinkohle AG (coal mining industry) in Hamm, Germany
09.2001 - 09.2002 Civilian service, digital subtraction angiography, University hospital Mainz,
Germany
Elected offices:
07.2004 - 07.2005 Chairman of the student council (Geology, University of Bonn)
07.2003 - 06.2004 Member of the student council (Geology, University of Bonn)
Publications:
Joachim, C. & Langer, M.R., 2008: The 80 most common Ostracods from the Bay of Fetovaia
Elba Island (Mediterranean Sea). University of Bonn, 28 pp., 10 plates.
Talks:
Paleogene Workshop, Leuven, Belgium, 2010.
Annual Meeting of the German Paleontological Society, Munich, Germany October 5th – 8th
2010.
1st Annual Meeting of BIOACID, Bremerhaven, Germany, Sept. 28th – 30th 2010 (joint meeting
with EPOCA (European Project on Ocean Acidification) and UKOARP (United Kingdom
Ocean Acidification Research Programme).
Annual Meeting of the German Paleontological Society, Vienna, Austria 2011.
2nd Annual Meeting of BIOACID, September 26th – 30th, University of Bremen, Germany 2011.
148
CURRICULUM VITAE
European Geologists Union (EGU), Vienna, April 2012.
Poster presentations:
German speaking Ostracodologists meeting in Braunschweig, Germany, June 26th – 27th 2008.
Annual Meeting of the German Paleontological Society in Erlangen, Germany, July 7th - 10th
2008.
1st Annual Meeting of BIOACID, Sept. 28th – 30th 2010, Bremerhaven, Germany (Joint meeting
with EPOCA (European Project on Ocean Acidification) and UKOARP (United Kingdom
Ocean Acidification Research Programme).
Annual Meeting of the German Paleontological Society München, Germany October 5th – 8th
2010.
International Nannoplankton Association (INA) Yamagata (Japan), Sept. 5th – 10th 2010.
Integrated Ocean Drilling Program (IODP) meeting in Münster, March 14th – 17th 2011.
Climate and Biota of the Early Paleogene (CBEP) in Salzburg June 5th – 8th 2011.
2nd Annual Meeting of BIOACID, September 26th – 30th at the University of Bremen, Germany
2011.
18/10/2011: Research School Ruhr University Bochum, Science College 2011 “My Doctorate
and I”.
149

The late Paleocene and early Eocene hyperthermal events

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