Change patterns in the trophic state of Lake Mamry Północne and

Transcription

Change9,
patterns
in the trophic state of Lake Mamry Północne and Lake Niegocin
Limnological Review
1: 39-60
39
Change patterns in the trophic state of Lake Mamry Północne and
Lake Niegocin (Masurian Lake District, Poland)
Bogusław Zdanowski, Arkadiusz Wołos, Małgorzata Wierzchowska
The Stanisław Sakowicz Inland Fisheries Institute, ul. Oczapowskiego 10, 10-719 Olsztyn, Poland, e-mail: [email protected]
Abstract: The purpose of the work was to test the hypothesis that the rate of improvement in water quality in lakes, which receive sewage
from point sources, can depend on hydrologic conditions, once the influx of sewage has been terminated. Multi-year physical, chemical,
and trophic data were analyzed for Lake Mamry Północne and Lake Niegocin, both of which are part of the Great Masurian Lake System.
This lake system, subject to varying degrees of human impact, is particularly valuable from an environmental, recreational, and economic
point of view. It has been shown that reduced influx of phosphorus and nitrogen into Lake Niegocin has reduced the rate of eutrophication
of the lake’s water. Increasingly lower phosphorus and nitrogen concentrations have been detected in the lake’s epilimnion with increasing
water transparency and the absence of large quantities of cyanoprokaryota. A portion of the lake’s supply of pollutants, including internal
pollutants released from lake bottom deposits, has been transferred, due to hydrologic factors, to neighboring lakes such as Lake Mamry
Północne. The lake has been shown to undergo eutrophication during the summer season with lower water transparency, increasing
phosphate and ammonia nitrogen concentrations near the bottom, as well as significant loss of oxygen content from the hypolimnion. It
has been shown that the monitoring of the location of the Pisa River and Węgorapy River drainage divide is fundamentally important in the
analysis of eutrophication rates in the lakes of interest.
Keywords: lakes, water retention, pollution, eutrophication, salinity, oxygen, phosphorus, nitrogen
Introduction
The eutrophication of water is a serious problem
in the management of water resources throughout the
world. It results in extensive plant growth, especially
phytoplankton, in affected bodies of water. The eutrophication of a body of water can result in a completely degraded natural environment. An affected body of water
can become partially or entirely useless for community,
recreational, industrial, and fishing purposes (Olszewski 1971a,b; Kajak 1979; Zdanowski 1982; Szczerbowski
et al. 1993).
Eutrophication is caused by the influx of allochthonous matter from sources in direct and total basins
(Bajkiewicz-Grabowska 2002; Marszelewski 2005). The
key element responsible for eutrophication is phosphorus. It regulates biological production, limits the growth
of algae, and determines the degree of eutrophication
in a given body of water (Vollenweider 1968; Schindler
1977). Phosphorus accelerates eutrophication, affecting
a range of lakes from primarily oligotrophic to prima-
rily eutrophic. In polytrophic and hypertrophic lakes,
the primary determinants of eutrophication are nitrogen and light (Zdanowski 1982; Kufel 1998).
Bodies of water at advanced stages of eutrophication can activate biogenic substances trapped in
sediments deposited at their bottom (Gawrońska 1994;
Kufel and Kalinowska 1997; Andersen and Ring 1999;
Perkins and Underwood 2001). Phosphorus and nitrogen loads released during internal loading processes can
yield significant nutrient concentrations, comparable to
concentrations produced by external loading from basin sources. (Søndergaard et al. 1999, 2001, 2003; Kozerski et al. 1999).
The purpose of the work was to test the hypothesis that the rate of improvement in water quality in
lakes, which receive sewage from point sources, can depend on hydrologic conditions, once the influx of sewage has been terminated. Multi-year physical, chemical, and trophic data were obtained for lakes Mamry
Północne and Niegocin. Both lakes are part of the Great
Masurian Lake System. This lake system, subject to var-
40
ying degrees of human impact, is particularly valuable
from an environmental, recreational, and economic
point of view.
Research sites
Lakes Mamry Północne and Niegocin are part
of the Great Masurian Lake District. This mesoregion
constitutes the western part of the Eastern Baltic Lake
District that stretches across the North European Plain,
which is the western part of the Precambrian Eastern
European Platform (Kondracki 2000). It is the largest
lake district in Poland, naturally interconnected or, in
some cases, linked by manmade canals (Fig. 1). It constitutes about 10% of total lake water surface in Poland
(Mikulski 1966; Choiński 1991).
The Great Masurian Lakes are located within a
drainage divide zone between the Wisła and Pregoła
river drainage basins. The water level in the lakes is
maintained via a system of dams. Major rivers in this
region are the Krutynia, the Jorka, the Orzysza, and
the Sapina. Water exits the lake system north via the
Węgorapa and the Pregoła and south via the Pisa and
Narew towards the Wisła River. The drainage divide in
the Great Masurian Lake System runs down the southern edge of Lake Kisajno at the Giżycki Canal (Mikulski
1966). The magnitude of the outflow of water via the
Pisa and the Węgorapa can vary during the year as well
as during each given hydrological year (Fig. 1).
The location of the drainage divide may change
from Lake Dargin in the north to Lake Mikołajskie in
the south, while at very low water levels, from Przystań
to Lake Śniardwy. In such cases, a certain area within
the drainage divide zone remains isolated from surface
runoff (Bajkiewicz-Grabowska 1991). Therefore, changes in water outflow direction, driven by changes in the
location of the drainage divide, can shape the chemistry
as well as the physical and biological conditions in the
lakes in question (Bajkiewicz-Grabowska 2008). Water
pollution from the middle zone of the Great Masurian
Lake District can then drift to lakes in the south as well
as Lake Mamry Północne.
Lake Mamry Północne is the northernmost of
the Great Masurian Lakes (Table 1, Fig. 1). It formed in
a bottom moraine depression. Water exits the lake via
the Węgorapa River. The parent material of the basin is
formed primarily of boulder clay as well as extensive alluvial formations and peat. The lake’s immediate vicinity is agricultural for the most part (Fig. 2) and the lake
did not have point sources of pollution.
Lake Niegocin is a large glacial lake featuring diverse bottom topography with multiple depressions and
expansive mid-lake shallows (Table 1, Fig. 3). The lake’s
direct basin is primarily agricultural in nature (Fig.
3). The lake used to receive municipal and industrial
wastewater in the past. A mechanical-biological wastewater treatment plant that utilizes chemical phosphorus
precipitation technology was put on line in November,
1994.
Materials and methods
The influence of drainage basins on rates of
lake-bound material delivery was assessed using a system proposed by Bajkiewicz-Grabowska (1987, 1990,
2002). The volume of surface runoff delivered to a lake
depends on the “effective size” of the basin delivering
material (effective size measured by propensity to allow
water to exit), average slope of the basin (which determines the rate of surface runoff and water erosion), river network density (a key determinant of direct-rapid
material transport to lakes), geologic structure and soil
conditions that determine the degree of soil permeability, which controls how much material is transported
Table 1. Limnological characteristics of lakes Mamry Północne and Niegocin
Lake
Mamry Północne
Niegocin
Area (ha)
2 504.0
2 600.0
Maximum depth (m)
43.8
39.0
Mean depth (m)
11.7
9.9
Volume (dam3)
298 300.0
258 521.6
Direct catchment area (km )
32.0
61.9
2
Total catchment area (km )
562.3
323.3
Mean annual outflow (hm3 yr-1)
90.2
69.9
Water residence time (yr)
3.3
3.7
2
Change patterns in the trophic state of Lake Mamry Północne and Lake Niegocin
Fig. 1. Great Masurian Lake System. Location of drainage divide (Bajkiewicz-Grabowska 1991, 2008; Dąbrowski 2002a,b)
41
42
Fig. 2. Land use in the direct drainage basin of Lake Mamry Północne. Water sampling sites in 2000-2001
to underground water reservoirs, and finally, land use,
which determines the amount and nature of biologically-active elements in surface runoff.
The above listed characteristics were determined
based on topographic maps (scale: 1: 25 000). Each
characteristic was assigned a grade ranging from 0 to
3 points. The grades were used to assign the basins of
interest to four susceptibility groups based on how well
they facilitate the delivery of material to the lakes in
question.
The lakes’ natural ability to resist basin influence
(method by Kudelska et al., 1983, 1994; modified by
Fig. 3. Land use in the direct drainage basin of Lake Niegocin. Water sampling sites in 2000-2001
43
44
Bajkiewicz-Grabowska 1987, 1990, 2002) was evaluated
based on average lake depth, the ratio of water capacity
to shoreline length, the water stratification percentage
(percentage of hypolimnion in total amount of water),
the ratio of hypolimnion surface area to epilimnion volume (a measure of biogenic substance circulation), average annual lake water exchange intensity (ratio of annual outflow to total lake volume), and Schindler’s coefficient, or the ratio of pollution absorbing areas (area of
basin plus area of lake) to lake volume.
Each indicator was assigned an appropriate number of points ranging from 0 to 3, where 0 represented a
high degree of resistance to deterioration, while 3 stood
for the lack thereof. A final grade was calculated as the
arithmetic average of point totals accumulated from the
different resistance characteristics considered for each
lake of interest. Each basin’s degree of susceptibility and
the lakes’ resistance categories were used to determine
each given lake’s ecological “basin-lake” system. This information was used to determine the rate of eutrophication in the two lakes of interest.
The Giercuszkiewicz-Bajtlik (1990) estimation
method was used to calculate the potential concentration of biogenic compounds in the lakes of interest. The
calculations were based on biogenic compound runoff
coefficients used by Giercuszkiewicz-Bajtlik (1990). The
calculated concentrations were tested using Vollenweider’s static and hydraulic model (1968, 1976).
Changes in the physical and chemical parameters
of the waters of lakes Mamry Północne and Niegocin
were investigated during the growing season (spring –
autumn) in the year 2000 at the deepest of locations in
each lake. The research was expanded in 2001 by the
addition of more sites – two on Lake Mamry Północne
and four on Lake Niegocin (Figs. 2, 3).
Temperature and oxygen content measurements
were performed using an oxygen sensor (YSI Model
#58) every one meter from the surface to the bottom
of each lake. Water transparency was measured using a
Secchi Disk. Chlorophyll as well as seston content were
determined in samples taken from the 0-10 meter layer
of water. Seston samples were filtered through a glass
fiber (45 μm) and dried at 105°C until they attained a
constant dry mass, at which point they were weighed
using a balance. Information on chlorophyll content in
the epilimnion was taken from works by NapiórkowskaKrzebietke (2004) as well as Napiórkowska-Krzebietke
and Hutorowicz (2005, 2006).
Water samples for laboratory analysis were collected from three different lake strata (subsurface: 0.5
m, metalimnion: 15 m, near-bottom: 0.5 m) using a
Ruttner water sampler. Standard laboratory methods
were used to analyze the samples (Standard Methods
1992; Hermanowicz et al. 1999)1. Hydrogen ion content
(pH) was determined using an electrometric method
(Sentron Model 2001 electrode). Electrolytic conductivity was measured using a WTW DIGI 610 conductometer.
Titration methods were used to determine carbon dioxide content and CODMn as well as carbonate,
bicarbonate, calcium, and magnesium concentrations.
The concentrations of sodium and potassium ions were
determined using a Zeiss flame photometer. Chloride
and nitrate ion concentrations were determined using
a Metrohm 690 ion chromatograph. A Schimadzu UV1601 spectrophotometer was used to colorimetrically
determine phosphate, total phosphorus, ammonia nitrogen, iron, and silicate concentrations, while an Epoll
ECO 20 spectrophotometer was used to determine total
nitrogen2 and nitrite content.
The lakes’ summer trophic state was determined
using Carlson’s Method (1977) based on transparency
measurements using Secchi’s Disk, total phosphorus
concentrations (Ptot), and chlorophyll content (Chl).
Poorly trophic waters (oligo-mesotrophic) were characterized by TSISD, TSIPtot, TSIChl values below 40, while
values between 40 and 60 were considered moderately
trophic (mesotrophic), and those over 60 were considered strongly trophic (eutrophic).
The paper includes data obtained from the Institute of Hydrobiology and Water Protection at the
Agricultural-Technical Academy in Olsztyn. The data
includes physical and chemical parameters of water
for Lake Niegocin calculated in 1978 as well as archival materials from the Institute of Inland Fishery Research concerning research on lakes Mamry Północne
and Niegocin from 1986-89 and 1990-99 (Zdanowski
and Hutorowicz 1994; unpublished IIFR data). Patterns in changes in physical and chemical parameters
of water were tested using nonparametric tests (MannWhitney’s U-Test and the Kruskal-Wallis test). The level
of significance was assumed to be p<0.05. The statistical analysis was performed using the Statistica software
package.
1
Sulfate concentrations were not determined from 1995 to 1999 and
from 2000 to 2001.
2
Total nitrogen content, that is the sum of the concentrations of organic
and inorganic compounds, was determined for Lake Mamry Północne only
during the summer seasons in 1991-1994 and 2000-2001. In the case of Lake
Niegocin, more information on changes in nitrogen content was obtained
during spring and autumn research efforts in the years mentioned above.
Results
Basin influence on lakes
The Lake Mamry Północne drainage basin is
characterized by a low degree of susceptibility to the activation of loads trapped in deposits embedded across
its surface as well as by a low probability that such loads
would be delivered to the lake (Group II susceptibility) (Table 2). Material runoff is limited by the geologic
structure of the basin. Other factors that unfavorably
impact runoff include a hydrological category lake and
a relative absence of outflow routes. The Lake Niegocin
basin is characterized by greater susceptibility to material delivery (Group III susceptibility). The delivery
of material to this lake is limited by its basin’s geologic
structure. Other limiting factors include a hydrological
category lake, land use, large swaths of farmland, and
built-up areas (Table 3). The set of limnological characteristics of Lake Mamry Północne make it a lake highly
resistant to eutrophication (first category of resistance).
On the other hand, a low degree of water stratification
in Lake Niegocin could have placed the lake in the second category of resistance (Table 3). The eutrophication
rate of this body of water may be said to be naturally
moderate.
It has been estimated, that in 2000-2001, the
drainage basin of Lake Mamry Północne was able to deliver phosphorus loads to the lake no larger than 0.13
g P m-2 yr-1 and nitrogen loads no larger than 1.61 g N
m-2 yr-1, values approaching a critical level (Table 4). On
the other hand, the lake’s total basin was able to deliver
phosphorus loads of 0.62 g P m-2 yr-1 and nitrogen loads
of 9.83 g N m-2 yr-1, values that exceed critical levels
threefold. The above mentioned loads were close to being tenfold larger than those estimated for the 1990s by
Giercuszkiewicz-Bajtlik and Głąbski (1981). Over 75%
of the load amounts came from spatial and scattered
sources such as agriculture, animal husbandry, recreation, as well as from the influx of “fertile” waters from
Lake Święcajty and the southern part of Lake Mamry.
Over the same period of time, the direct basin
of Lake Niegocin was able to deliver a phosphorus load
(0.67 g P m-2 yr-1) close to three times the critical level
and a nitrogen load (4.30 g N m-2 yr-1) close to twice the
critical level. The lake’s total basin, on the other hand,
was able to deliver a nitrogen load five times the criti-
Table 2. Basin influence on lakes Mamry Północne and Niegocin
Index
Mamry Północne
Niegocin
Ohle’s index*
1 (25.31)
1 (15.47)
Type of the water balance
3 (flow through)
3 (flow through)
1 (0.95)
1 (0.52)
Channel network density (km km-2)
Mean catchment slope (m km )
1 (5.21)
1 (7.61)
Outflow-less areas (%)
3 (14.8)
2 (44.1)
-2
Direct catchment geology
0 (clayey, peaty)
0 (clayey)
Land use in the direct catchment
1 (forest-agricultural)
3 (forest-agricultural with built-up areas)
Group of the susceptibility of the drainage area to supplies of
matter to the lake
1.4 (II)
1.6 (III)
*Catchment area to lake area ratio
Table 3. Susceptibility to degradation of lakes Mamry Północne and Niegocin
Index
Mean depth (m)
Mamry Północne
Niegocin
0 (11.7)
1 (9.9)
Lake volume (dam ) to shoreline length (m) ratio
0 (8.8)
0 (7.3)
Thermal stratification (%)
1 (24.0)
3 (7.1)
3
Active bottom area (m2) to epilimnion volume (m3) ratio
0 (0.08)
0 (0.07)
Flushing rate (yr-1)
3 (0.30)
3 (0.27)
Schindler’s index* (m-1)
0 (2.16)
0 (1.66)
Category of the susceptibility of the lake to degradation
I (0.7)
II (1.2)
* Catchment area (with the lake) to lake volume ratio
45
46
Table 4. Estimated potential influx of phosphorus and nitrogen to Lake Mamry Północne from its direct and total drainage basins in 20012002
Catchment
Source
direct
total
direct
P (kg yr-1)
total
N (kg yr-1)
Point1
Spatial
1 502
7 679
32 562
164 075
Dispersed (from pig farming)
931
4 007
3 725
16 029
Precipitation
887
3 905
3 860
65 620
Bathing beaches
5
24
100
376
Linear
1
2
2
5
Real load of phosphorus and nitrogen to the lake (g m-2 yr-1)
0.133
0.624
1.607
9.832
Critical load of phosphorus and nitrogen to the lake (g m
rok-1)
0.109-0.219
0.111-0.2223
-2
2
1.75-3.502
1
Point sources of pollutant weren’t identified
2
According to Vollenweider (1968) on the basis of a criterion of the mean depth
3
According to Vollenweider (1976) on the basis of a hydraulic criterion
cal level and a nitrogen load four times the critical level
(Table 5). However, the above mentioned phosphorus
and nitrogen loads were only a third of their predicted values (Giercuszkiewicz-Bajtlik and Głąbiki 1981;
Giercuszkiewicz-Bajtlik 1990). The principal reason for
this discrepancy was a decrease in pollution entering
the lake as a result of a wastewater treatment plant being put on line. The amount of phosphorus entering the
lake along with other types of pollution decreased close
to twentyfold in 2000-2001 to 0.11 g P m-2 yr-1 while the
amount of incoming nitrogen decreased threefold to
3.17 g N m-2 yr-1 relative to values predicted by Giercusz-
kiewicz-Bajtlik and Głąbski (1981) for the 1990s. These
values constitute only 10% (phosphorus) and 25% (nitrogen) of the lake’s total pollutant content.
Thermal and oxygen conditions in the lakes
Lakes Mamry Północne and Niegocin are dimictic lakes, mixing twice a year during the spring and autumn. Both can also be classified as third degree static
bodies of water – highly susceptible to the mixing of
water in the epilimnion during the summer stagnation
period (Hutchinson 1957; Olszewski and Paschalski
1959; Patalas 1960a,b).
Table 5. Estimated potential influx of phosphorus and nitrogen to Lake Niegocin from its direct and total drainage basins in 2001-2002
Catchment
Source
direct
total
direct
P (kg yr )
Point
total
N (kg yr )
-1
-1
2 738
82 399
Spatial
3 387
7 437
57 982
148 147
Dispersed (from pig farming)
12 276
14 985
45 745
56 579
Precipitation
1 773
2 297
7 720
38 600
Bathing beaches
16
33
314
651
21
Linear
6
8
16
Real load of phosphorus and nitrogen to the lake (g m-2 yr-1)
0.671
1.058
4.299
Critical load of phosphorus and nitrogen to the lake (g m-2 rok-1)
0.098-0.198
0.101-0.2053
2
2
According to Vollenweider (1968) on the basis of a criterion of the mean depth
3
According to Vollenweider (1976) on the basis of a hydraulic criterion
1.580-3.170
12.554
2
Water temperature in both lakes’ surface strata
ranged from 2.8°C to 24°C, while in the lakes’ bottom
strata, temperatures ranging from 2.8°C to 11.2°C were
recorded during the research period. Thermal stratification usually set in at the end of May and lasted until
October. The epilimnion reached 10 m during the peak
of the growing season while the hypolimnion remained
under 16 m (Figs. 4, 5). Epilimnion water temperature
in both lakes fluctuated between 17.1°C and 24.0°C
during the summer (July/August) stagnation period.
Water temperature in bottom strata was somewhat
lower in Lake Mamry Północne (< 9.0°C) versus Lake
Niegocin (< 10.0°C). Epilimnion covered 55% of the active bottom in Lake Mamry Północne and 46% in Lake
Niegocin.
Oxygen content in the surface stratum of Lake
Mamry Północne fluctuated between 8.0 mg l-1 and
15 mg l-1, while in Lake Niegocin, between 6.2 mg l-1
and 16.2 mg l-1. In the bottom strata of Lake Mamry
Północne, oxygen content fluctuations ranged from 0
mg l-1 and 13.8 mg l-1, while in Lake Niegocin, corresponding fluctuations ranged from 0 mg l-1 to 14.6 mg
l-1. The surface waters of Lake Niegocin were found to be
more saturated with oxygen than those of Lake Mamry
Północne. Loss of oxygen near the bottom was substantially greater in Lake Niegocin during the summer period. Trace amounts of oxygen at the bottom of Lake
Mamry Północne were not recorded until 1995-2001.
Significant loss of oxygen in Lake Mamry
Północne was observed only in the metalimnion, while
in Lake Niegocin, loss of oxygen was observed already
in the lower layer of the epilimnion. Trace amounts of
oxygen were always detected during the summer in the
metalimnion and the hypolimnion of Lake Niegocin.
Changes in oxygen content along the vertical cross section of Lake Mamry Północne can be described using a
negative heterograde curve, typical for b-type mesotrophic lakes (Fig. 4). Oxygen content in the metalimnion
of this lake can fall as low as 1.2 mg l-1. Oxygen content
in the hypolimnion generally fluctuated between 1.3
mg l-1 and 5.1 mg l-1, which is a saturation range between 10.7% and 42.4%. A clinograde curve was used to
represent changes in oxygen content along the vertical
cross section of Lake Niegocin. Such a curve is typical
for lakes affected by a substantial degree of eutrophication (Fig. 5).
Lake water salinity
The electrolytic conductivity of water, a measure
of salinity levels and mineral salt content dissolved in
47
water, was 50 μS cm-1 lower in Lake Mamry Północne
than in Lake Niegocin, a lake where untreated sewage
had been dumped until 1994. Bottom layers tended to
have higher electrolytic conductivity during the summer, approximately 20-30 μS cm-1 higher (Fig. 6).
A statistically significant increase in the electrolytic conductivity of water (Mann-Whitney’s UTest), U=0, p=0.004) was detected in Lake Mamry
Północne in 2000-2001, both in the surface layer and
in the bottom layer. In Lake Niegocin, an increase was
detected only in the bottom layer (Kruskal-Wallis Test,
H=7.6831, p=0.021). No meaningful differences in electrolytic conductivity were detected between the different sampling sites on both lakes. No meaningful differences were observed among the various sampling sites
in terms of calcium, magnesium, potassium, sodium,
bicarbonate, chloride, and silicate concentrations either
– the one exception being the sewage entry point on
Lake Niegocin3.
The bicarbonate-based and lime-based salinity
of both lakes as well as that of other lakes in the area
(Patalas 1960c; Zdanowski 1982, 1983, Zdanowski et
al. 1984; Korycka 1991; Zdanowski and Hutorowicz
1994; Marszelewski 2005) was inferred from the lakes’
high calcium content and smaller amounts of other cations present (Fig. 7). Calcium content in Lake Mamry
Północne has increased in recent years (Kruskal-Wallis
Test, H=13.8236, p=0.0032) by about 10 mg l-1, fluctuating on average between 45 and 52 mg l-1 (Fig. 8). On the
other hand, calcium content in Lake Niegocin, characterized by higher calcium levels, initially increased quite
rapidly, especially near the bottom of the lake (KruskalWallis Test, H=15.0512, p= 0.046) (Fig. 8). Calcium
levels dropped both in surface and bottom strata of the
lake to about 50 mg l-1 only when the wastewater treatment plant went on line (Fig. 8). Increasing calcium
concentration in Lake Mamry Północne was associated
by increasing levels of bicarbonate, as was the case in
Lake Niegocin (Fig. 9).
Carbon dioxide was produced in the surface layer when pH decreased below 8.25. Its maximum levels
reached 0.96 mg l-1 in Lake Mamry Północne and 1.20
mg l-1 in Lake Niegocin. While carbonate was not analyzed for at the time, it was a component of total salinity during the growing season (spring – early autumn)
when phytoplankton production remains strong , which
led to a higher pH. Trace amounts of carbon dioxide in
3
Electrolytic conductivity of water at the sewage point of entry increased
to 700 μS cm-1 in 1978, while calcium content increased to 80 mg l-1, chloride
content to 60 mg l-1, bicarbonate content to 350 mg l-1, potassium content to 8
mg l-1 sodium content to 45 mg l-1, and silicate content to 14 mg l-1.
48
Fig. 4. Thermal-oxygen strata in Lake Mamry Północne during the summer stagnation period in 1986-1994 (A) and 1995-2001 (B)
Fig. 5. Thermal-oxygen strata in Lake Niegocin during the summer stagnation period in 1978-1994 (A) and 1995-2001 (B)
49
50
Fig. 6. Electrolytic conductivity of water (mean, standard error, standard deviation) during the summer season within the surface stratum
(a) and the bottom stratum (b) in Lake Mamry Północne (A) and Lake Niegocin (B)
Fig. 7. Average calcium, magnesium, sodium, and potassium content (%) in total cations concentration during the summer season in the
surface stratum (a) and bottom stratum (b) of Lake Mamry Północne (A) and Lake Niegocin (B)
51
Fig. 8. Calcium content (mean, standard error, standard deviation) during the summer season in the surface stratum (a) and bottom stratum
(b) of Lake Mamry Północne (A) and Lake Niegocin (B)
Fig. 9. Bicarbonate content (mean, standard error, standard deviation) during the summer season in the surface stratum (a) and bottom
stratum (b) of Lake Mamry Północne (A) and Lake Niegocin (B)
52
bottom strata, the presence of carbonate, and elevated
pH (over 8.25) were noted only during the spring, usually in Lake Niegocin
Magnesium content, while somewhat higher in
Lake Niegocin (by approx. 2 mg l-1), did not change over
the investigated multi-year period. Likewise, no changes in potassium levels were discovered in either lake.
Sodium and chloride concentrations in Lake Niegocin,
usually higher than those in Lake Mamry Północne, fell
only after the wastewater treatment plant went on line
(Figs. 10, 11). A similar decrease in silicate and iron dissolved in the waters of Lake Niegocin was also detected.
Salinity levels and degrees of buffering were ultimately driven by calcium content in both lakes. The
functioning of the carbonate system, at a given calcium
concentration, prevented drastic changes in pH. The
hydrogen ion concentration was higher in the surface
strata of Lake Niegocin than in those of Lake Mamry
Północne. pH levels indicated higher primary production levels during the spring-summer period as well as
more intensive decalcification of water and the coprecipitation of phosphorus into lake bottom deposits.
The lakes’ supply of biogenic compounds
The epilimnion waters of Lake Mamry Północne
were characterized by a phosphorus supply (0.060 mg
l-1) three times smaller than that in Lake Niegocin
(0.200 mg l-1). The amount of phosphorus in the bottom
layer of Lake Mamry Północne was four times smaller
(on average: 0.090 mg l-1) than that in Lake Niegocin
(on average: 0.360 mg l-1) (Fig. 12). The highest of phosphorus concentrations in surface layers (0.456 mg l-1)
and bottom layers (0.870 mg l-1) were recorded in Lake
Niegocin prior to the construction of the wastewater
treatment plant.
Phosphate was detected in the epilimnion of
Lake Mamry Północne usually only in trace amounts
– no greater than 20% of total phosphorus content.
Phosphate content in the lake’s bottom layer constituted about 70% of total phosphorus. On the other hand,
phosphate content in the epilimnion of Lake Niegocin
constituted about 70% of total phosphorus, while near
the bottom, it was 90%.
No significant change patterns in phosphorus
content were detected in the surface waters of Lake
Mamry Północne (Fig. 12). The lake’s bottom strata do
experience elevated phosphorus levels in the summer
and autumn. Lake Niegocin has been shown to experience a significant decline in surface water phosphorus
(Kruskal-Wallis Test, H=14.6204, p=0.0056) and a gen-
eral tendency of reduced phosphorus content in bottom
strata throughout the growing season (Fig. 12). Despite
this fact, the lake’s phosphorus supply, both in surface
and bottom strata, was still twice that of Lake Mamry
Północne.
Lake Niegocin’s supply of nitrogen was usually twice that of Lake Mamry Północne, however, this
ceased to be the case once the wastewater treatment
plant went on line (Fig. 13). The recent increase in nitrogen concentration in Lake Mamry Północne erased
the trophic difference between the two lakes in terms of
nitrogen content. Organic compounds were the main
component of total nitrogen in the epilimnion of both
lakes. Mineral nitrogen (nitrate, nitrite, ammonia)
constituted about 5% of total nitrogen in Lake Mamry Północne and about 25% of total nitrogen in Lake
Niegocin.
Ammonia nitrogen (about 80% of total nitrogen)
played a key role in changes in nitrogen content in the
bottom strata of both lakes. Its concentration did not
exceed 0.46 mg l-1 during the summer in Lake Mamry
Północne, while in Lake Niegocin, it was always higher.
Ammonia nitrogen content did not exceed 2.96 mg l-1
before the opening of the wastewater treatment plant,
while afterwards, it stood at 1.71 mg l-1. Such high ammonia and phosphate concentrations near the bottom
of a lake are a sign that lake bottom deposits are still releasing ions, which means that eutrophication still plays
a key role in the lake.
No appreciable differences in nitrogen and phosphorus content were observed in the open waters of
Lake Mamry Północne. Only at sampling site #3, isolated by Upałty Island, were larger concentrations of
total phosphorus recorded (below 0.250 mg l-1, primarily phosphate). Ammonia nitrogen content at this site
was recorded at under 1.20 mg l-1 and no oxygen was
found in bottom strata. Nitrogen and phosphorus concentrations did not vary across the open waters of Lake
Niegocin – the one exception being the sewage point
of entry. Total phosphorus, total phosphate, total nitrogen, and ammonia nitrogen content in the surface layer
(1978) had been an order of magnitude greater (2.0 mg
l-1, 1.9 mg l-1, 32.0 and 12.0 mg l-1, respectively) prior to
the construction of the wastewater treatment plant.
Water transparency
Water transparency in lakes featuring natural
trophic succession, as determined by the visibility of
Secchi’s Disk, depends on the amount of suspended
matter (including phytoplankton) floating in the water
53
Fig. 10. Sodium content (mean, standard error, standard deviation) during the summer season in the surface stratum (a) and bottom stratum (b) of Lake Mamry Północne (A) and Lake Niegocin (B)
Fig. 11. Chloride content (mean, standard error, standard deviation) during the summer season in the surface stratum (a) and bottom stratum (b) of Lake Mamry Północne (A) and Lake Niegocin (B)
54
Fig. 12. Phosphorus content (mean, standard error, standard deviation) during the summer season in the surface stratum (a) and bottom
Fig. 13. Total nitrogen content (mean, standard error, standard deviation) during the summer season in the surface stratum (a) and bottom
over the disk (Szczepański 1968). It is a basic indicator
of the increasing eutrophication of water (Vollenweider
1968; Carlson 1977). Lower transparency was noted in
both lakes during the summer period (Fig. 14); in Lake
Mamry Północne, 4.0 m on average; in Lake Niegocin,
1.5 m on average. It was determined that this was due to
increased quantities of suspended matter in the lake water. In Lake Mamry Północne, 2.0 mg dm-3 of suspended
matter were detected, while in Lake Niegocin, about 6.0
mg l-1 were detected. Higher levels of CODMn were also
recorded: approx. 10 mg O2 l-1 (Lake Mamry Północne),
approx. 13 mg O2 l-1 (Lake Niegocin). CODMn is a measure of the quantity of organic matter susceptible to mineralization.
Analysis of multi-year water transparency data
indicates a reduction in Lake Mamry Północne (as low
as 2.0 m) and an increase in Lake Niegocin (over 1.0
m) during the last research period (Kruskal-Wallis Test,
H=15.3566, p=0.0040) (Fig. 14). The aforementioned
changes corresponded to intensive phytoplankton development in Lake Mamry Północne where chlorophyll
a content increased up to 14.9 mg m-3. Less intensive
phytoplankton development was noted in Lake Niegocin as was a lower concentration of chlorophyll (as low as
46.5 mg m-3). No appreciable differences in water transparency, seston content, and oxygen consumption were
observed between different sampling sites on each lake.
Changes in water transparency in both lakes depended more on seston content than chlorophyll content. Seston content changes in Lake Mamry Północne
accounted for 47% of the changes in Secchi’s Disk visibility (R2=0.4735, p=0.007), while chlorophyll account-
55
ed for only 28% (R2=0.277, p=0.036). In Lake Niegocin,
seston content in the epilimnion accounted for 71% of
changes in visibility (R2=0.706, p<0.001) while chlorophyll content accounted for 46% (R2 = 0.456, p=0.001).
No correlation was established between phosphorus content and chlorophyll content in either lake. In
Lake Mamry Północne, changes in chlorophyll content
could have been related to changes in nitrogen content
(R2=0.580, p=0.028).
Based on the water transparency index (WSTSD
– 37-50) and the chlorophyll content index (WSTChl –
45-59), the epilimnion of Lake Mamry Północne can
usually be classified as mesotrophic. The phosphorus
concentration index (WSTTP – 36-70) varied in a manner characteristic of waters experiencing advanced
eutrophication. The water transparency index (WSTSD
– 42-62) for Lake Niegocin was characteristic of mesotrophic waters. The lake’s phosphorus content index
(WSTTP – 67-90) and chlorophyll content index (67-71)
are characteristic of advanced eutrophy, given the quantity of cyanobacteria present. An increase in the fertility
of water has been observed in Lake Mamry Północne
during the most recent research period. A decrease was
observed in Lake Niegocin during the same time period.
Discussion
Large-scale runoff containing biogenic compounds has been the prime determinant of trophic conditions in Lake Mamry Północne. Potential phosphorus
and nitrogen loads arriving from the lake’s total basin in
Fig. 14. Changes in water transparency (mean, standard error, standard deviation) during the summer season in Lake Mamry Północne (A)
and Lake Niegocin (B)
56
2000-2001 were three times larger than critical values
and ten times larger than values predicted by Giercuszkiewicz-Bajtlik and Głąbski (1981). The lake’s direct basin also contributed biogenic compounds but the contribution was much smaller than that of Lake Niegocin’s
direct basin. The direct basin of Lake Mamry Północne
contributed only 20% of the lake’s total biogenic compound content, which did not exceed critical values.
The progressive eutrophication of Lake Mamry
Północne can be discerned from changing epilimnion
phosphorus concentrations (< 0.100 mg l-1), water transparency as low as 2.0 m, and significant loss of oxygen
from the hypolimnion during the summer (up to 11%
saturation) compared to earlier research (Gieysztor and
Odechowska 1958; Zachwieja 1975; Gliwicz et al. 1980;
Soszka et al. 1979; Zdanowski et al. 1984; Zdanowski
and Hutorowicz 1994; Wróblewska 2002). Increasing
loss of oxygen as well as increasing phosphate and ammonia nitrogen concentrations at the lake’s bottom may
indicate the release of biogenic compounds from lake
bottom deposits. Such deposits may play a significant
role in the internal generation of biogenic compounds
that shape the trophic conditions in the lake. Physical
and chemical data were used to classify the lake as Class
II in terms of water purity (Wróblewska 2002), and as
mesotrophic based on Carlson’s trophic indicators presented in this paper. Finally, given a lack of point sources feeding the lake pollution, it can be classified as Class
I in terms of water purity.
A rise in the fertility of water in Lake Mamry
Północne has also been shown by phytoplanktonbased research (Napiórkowska-Krzebietke 2004; Napiórkowska-Krzebietke and Hutorowicz 2005). Most of
the plankton and chlorophyll present can be attributed
to cyanobacteria, represented in this case by common
species such as Microcystis aeruginosa and Leptolingbya
thermalis, characteristic of lakes undergoing eutrophication. Their growth in this lake will depend on access
to nitrogen.
Lake Niegocin had been considered one of the
most polluted lakes in Poland, mainly because of the
raw sewage being dumped directly into the lake (Bernatowicz et al. 1974; Spodniewska 1978, 1979; Gliwicz
et al. 1980; Zdanowski et al. 1984; Niewolak 1989;
Giercuszkiewicz-Bajtlik 1990; Korycka 1991; Dorochowicz 1994; Zdanowski and Hutorowicz 1994; Kufel and
Kufel 1999; Cydzik and Soszka 2003). Phosphorus loads
(2.73 g P m-2 yr-1) and nitrogen loads (9.59 g N m-2 yr1
) delivered in this manner exceeded then-recognized
standards for lake water quality (Giercurszkiewicz-
Bajtlik and Głąbski 1981; Giercuszkiewicz-Bajtlik 1990;
Zdanowski and Hutorowicz 1994). As a result, the lake
was characterized by a substantial supply of phosphorus
and nitrogen, which reached 0.300 mg Ptot l-1 and 2.5 mg
Ntot l-1 in the spring. The lake was classified as polytrophic, strongly eutrophic, and featuring very bad water,
bad beyond any normal classification system.
Poor water quality in Lake Niegocin is, first of all,
the result of poor sanitary conditions: extensive bacterial plankton, heterotrophic bacteria including excrement bacteria Escherichia coli and excrement streptococci, as well as filiform and yeast-type fungi (Niewolak
1989). Other indicators of poor water quality were lack
of oxygen in the metalimnion and the hypolimnion
(Zdanowski et al. 1984; Zdanowski and Hutorowicz
1994), low transparency of water (approx. 1.0 m), extensive presence of phytoplankton, including cyanoprokaryota (Spodniewska 1978, 1979; Kufel and Kufel
1999; Napiórkowska-Krzebietke 2004; NapiórkowskaKrzebietke and Hutorowicz 2006), lack of oxygen and
the presence of hydrogen sulfide in the hypolimnion,
rapid increases in the summertime concentrations of
biogenic compounds (phosphate, ammonia nitrogen)
in near-bottom strata, and an increase in water salinity (Zdanowski et al. 1984; Zdanowski and Hutorowicz
1994).
The fertility of the lake’s water also depended on
the intensity of changes in lake bottom deposits. Oxygen deficits in the hypolimnion could increase the rate
of release of large amounts of phosphate and ammonia
nitrogen trapped in lake bottom deposits. According
to Patalas (1960c), this type of activation mechanism
of biogenic compounds is driven by the dynamics of
masses of water. Such conditions are believed to exist in
Lake Niegocin, given the significant percentage of the
lake’s bottom (46%) taking part in seasonal and multiyear matter exchange cycles.
A low nitrogen to phosphorus ratio (N/P) during
the summer indicated that nitrogen was a limiting factor
in the development of algae. The ratio had been roughly
7 prior to the construction of the wastewater treatment
plant. This situation is characteristic of polytrophic and
polluted lakes (Forsberg et al. 1978; Zdanowski 1982).
At an N/P ratio of less than 10, an extensive presence of
cyanoprokaryota can be expected to develop, especially
those adapted to binding free atmospheric nitrogen dissolved in water. Quantities of nitrogen introduced into
the water system by cyanobacteria can be significant,
reaching 50% of annual content in the lake (Jaworska
2004). Research studies by Napiórkowska-Krzebietke
(2004) as well as Napiórkowska-Krzebietke and Hutorowicz (2006) have shown that extensive development
of phytoplankton is driven mainly by filiform cyanobacteria of the Aphanizomenon flos-aquae type as well
as cyanobacteria of the Planktotrix agardhii type, which
constituted over 80% of total biomass. Phytoplankton
development was deemed rapid, given the high concentrations of chlorophyll detected (up to 100 mg l-1). The
high rate of biomass development, in light of the toxins
biomass can emit into the environment, could threaten
the existence of other aqueous organisms including fish.
A modern wastewater treatment plant was put
on line in 1994, featuring chemical phosphorus precipitation technology. This significantly reduced the
amount of phosphorus-bearing sewage flowing into
the lake – by about 90% or 0.11 g P m-2 yr-1. Nitrogen
influx was reduced 75% or 3.17 g N m-2 yr-1. This reduction in the lake’s phosphorus and nitrogen levels, as
seen in the physical and chemical data tables presented
herein, was able to cut the rate of eutrophication in the
lake. The lower eutrophication rate can be discerned
from decreasing phosphorus and nitrogen levels in the
lake’s epilimnion, increasing transparency of water, and
a general increase in total lake water salinity including
lower concentrations of calcium and bicarbonate. A
decrease in phosphate and ammonia concentrations in
bottom water layers during the summer stagnation period, despite a lack of improving oxygen conditions in
the hypolimnion, may indicate a reduction in the rate of
release of biogenic compounds trapped in lake bottom
deposits.
A similar reaction by a lake following a halt in the
influx of sewage was observed by Choiński et al. (1998),
Romero et al. (2002), Raike et al. 2003, and Moss et al.
(2005). Reductions in phosphorus influx usually led
to smaller quantities of total plankton algae (biomass)
(Anneville and Pelletier 2000). The quantity of cyanobacteria in total algae biomass would also decrease. Algae is an important indicator of improving water quality in lakes. According to Napiórkowska-Krzebietke
(2004), the smaller amount of phytoplankton biomass
present in Lake Niegocin in recent years consists of eurytopic species.
Improvement in Lake Niegocin’s water quality has also been confirmed by recent research studies
(Wróblewska 2002). The research has shown that the
lake is now a Class III lake in terms of water purity,
and total nitrogen content has fallen from very high to
Class II water quality. Changes have also been observed
in the qualitative composition of phytoplankton. These
57
include the presence of more brittleworts, the absence
of significant quantities of cyanoprokaryota, and a lack
of hydrogen sulfide in lake bottom strata. In terms of
sanitary conditions, the lake could now be classified as
a Class I water quality lake.
Perhaps the most effective way to lower the trophic state in Lake Niegocin is to improve water and
sewage management practices as well as implement a
complex drainage basin land use program that would
limit runoff containing biogenic compounds. Such
a recommendation was put forth by Lossow (1998),
Łopata (2005), as well as Gawrońska and Lossow (2008)
with regard to the protection of other lakes that resemble Lake Niegocin in terms of pollution and recultivation goals. Calculated phosphorus and nitrogen loads
delivered to the lake in 2000-2001 by its direct basin
as well as total basin still substantially exceed critical
permissible loading values for lakes. Hydrologic conditions in the area have resulted in a portion of the aforementioned phosphorus and nitrogen pollution going to
neighboring lakes along with some originating in lake
bottom deposits.
In light of Vollenweider’s fundamental OECD report published 40 years ago (1968) where the causes and
effects of surface water eutrophication were described,
Olszewski’s views on the protection of water (1971 a,b),
other extensive publications on the subject of the eutrophication of water, as well as the multi-year research
efforts presented herein, the case of Lake Niegocin, a
lake located on a drainage divide, as a sewage dumping
ground must be considered an anachronism. Years of
pollution deposits collecting in the lake have resulted
in a persistently elevated fertility level of the lake’s waters as well as eutrophication of other lakes in the Great
Masurian Lake System. This is the case despite the construction of a modern wastewater treatment plant in
1994, featuring phosphorus precipitation technology,
which in itself was a significant step in attempts to protect the lake from eutrophication. The changing location of the drainage divide between the Węgorapa and
Pisa rivers, as shown by Bajkiewicz-Grabowska (2008),
creates ample opportunities for pollution to drift from
lake to lake along with surface runoff, which takes pollution into lakes in the south as well as into the Mamry
lake system. The process of cleaning up large quantities
of pollution and limiting surface runoff containing biogenic compounds from other sources will take a long
time and is certain to involve other lakes, hydrologically
connected to Lake Niegocin.
58
References
Andersen F.O., Ring P., 1999, Comparison of phosphorus release from littoral and profundal sediments in a shallow,
eutrophic lake, Hydrobiologia 395-396: 175-183.
Anneville O., Pelletier J.P., 2000, Recovery of Lake Geneva
from eutrophication: quantitative response of phytoplankton, Arch. Hydrobiol. 148(4): 607-624.
Bajkiewicz-Grabowska E., 1987, Ocena naturalnej podatności
jezior na degradację i rola zlewni w tym procesie (Evaluation of natural susceptibility of lakes to degradation and
the role of catchment in this process) , Wiad. Ekol. 33(3):
279-289 (in Polish).
Bajkiewicz-Grabowska E., 1990, Stopień naturalnej podatności jezior na eutrofizację na przykładzie
wybranych jezior Polski (Degree of natural susceptibility
of lakes to eutrophication on the example of selected Polish lakes), Gosp. Wodna 12: 270-272 (in Polish).
Bajkiewicz-Grabowska E., 1991, Czy zaszły zmiany w położeniu działu wodnego w systemie Wielkich Jezior Mazurskich? (Whether changes in the location of watershed in
the system of the Great Masurian Lakes took place?), Pr.
Stud. Geogr. UW 12: 269-278 (in Polish).
Bajkiewicz-Grabowska E., 2002, Obieg materii w systemach
rzeczno-jeziornych (Cirkulation of matter in the riverlake systems), Wyd. UW, Warszawa: p. 274 (in Polish,
English summary).
Bajkiewicz-Grabowska E., 2008, Obieg wody w systemie
Wielkich Jezior Mazurskich (Water circulation in the
Great Masurian Lakes system), [in:] Jasser I., Robak S.,
Zdanowski B. (eds) Ochrona i rekultywacja wód Wielkich
Jezior Mazurskich narzędziem rozwoju naukowego, gospodarczego, społecznego i kulturowego regionu (Protection and restoration of the Great Masurian Lakes waters
as a tool of scientific, economic, social, and cultural development of the region), Wyd. IRS, Olsztyn: 19-29 (in
Polish).
Bernatowicz S., Hillbricht-Ilkowska A., Kajak Z., Rybak J.I.,
Turczyńska J., Węgleńska T., 1974, Charakterystyka limnologiczna jeziora Niegocin na tle postępującej eutrofizacji (Limnological characterization of Lake Niegocin
relating to the progressing eutrophication), Zesz. Nauk.
ART Olsztyn 3: 149-172 (in Polish).
Carlson R.E., 1977, A trophic state index for lakes, Limnol.
Oceanogr. 22: 361-369.
Choiński A., 1991, Katalog jezior Polski. Część druga: Pojezierze Mazurskie (Inventory of Polish lakes. Second part:
Masurian Lakeland), Wyd. UAM, Poznań, p. 157 (in Polish).
Cydzik D., Soszka H., 2003, Changes in water quality of Polish lakes in the years 1991-2000 (based on lake monitoring results), Limnol. Rev. 3: 53-58.
Dąbrowski M., 2002a, Położenie głównego działu wodnego
w systemie Wielkich Jezior Mazurskich (Location of the
main watershed in the system of Great Masurian Lakes),
Gosp. Wodna 6: 238-243 (in Polish).
Dąbrowski M., 2002b, Changes in water level of lakes in
northeastern Poland, Limnol. Rev. 2: 85-92.
Dorochowicz A., 1994, Stan czystości systemu Wielkich
Jezior Mazurskich w latach 1982-1993 (State of water
quality of the Great Mazurian Lakes system in the years
1982-1993), PIOŚ, WIOŚ, Bibl. Monitoringu Środowiska,
Suwałki: p. 55 (in Polish).
Forsberg C., Rydnig S.O., Claesson A., Forsberg A., 1978, Water chemical analyses and/or algal assay? Sewage effluent
and polluted lake water studies, Mitt. Int. Ver. Limnol.,
21: 352-363.
Gawrońska H., 1994, Wymiana fosforu i azotu pomiędzy osadami a wodą w jeziorze sztucznie napowietrzanym (The
exchange of phosphorus and nitrogen between sediments
and water in an artificially aerated lake), Acta Acad. Agricult. Tech. Olst. Protectio Aquarum et Piscatoria 19 suppl.
E: 3-49 (in Polish).
Gawrońska H., Lossow K., 2008, Rekultywacja jezior –
ograniczenia i wskazania praktyczne (Restoration of lakes
– limitations and practical recommendations), [in:] Jasser
I., Robak S. Zdanowski B. (eds) Ochrona i rekultywacja
wód Wielkich Jezior Mazurskich narzędziem rozwoju
naukowego, gospodarczego, społecznego i kulturowego
regionu (Protection and restoration of the Great Masurian Lakes waters as a tool of scientific, economic, social,
and cultural development of the region), Wyd. IRS, Olsztyn: 101-118 (in Polish).
Giercuszkiewicz-Bajtlik M., Głąbski E., 1981, Predicting the
pollution of Great Masurian Lakes from point and nonpoint sources, Ekol. Pol. 29(3): 361-374.
Giercuszkiewicz-Bajtlik M., 1990, Prognozowanie zmian
jakości wód stojących (Predicting of quality changes in
stagnant waters), Wyd. IOŚ, Warszawa, p. 74 (in Polish).
Gieysztor M., Odechowska Z., 1958, Observation on the
thermal and chemical properties of Mazurian Lakes in
the Giżycko Region, Pol. Arch. Hydrobiol. 4: 123-152.
Gliwicz Z.M., Kowalczewski A., Ozimek T., Pieczyńska E.,
Prejs A., Prejs K., Rybak J.I., 1980, Ocena stopnia eutrofizacji Wielkich Jezior Mazurskich (Assesment of the eutrophication degree of the Great Masurian Lakes), Wyd,
Akcydensowe, Warszawa, p. 103.
Hermanowicz W., Dożańska W., Dojlido J., Koziorowski
B., 1999, Fizyczno-chemiczne badanie wody i ścieków
(Physico-chemical examination of water and wastwater),
Wyd. „Arkady”, Warszawa, p. 555 (in Polish).
Hutchinson E.G., 1957, A treatise on limnology, John Wiley
and Sons, New York, p.1015.
Jaworska B., 2004, Sukcesja fitoplanktonu w Jeziorze Kortowskim (Phytoplankton succession in Lake Kortowskie),
UWM, Olsztyn, p. 77 (dissertation) (in Polish).
Kajak Z., 1979, Eutrofizacja jezior (Eutrophication of lakes),
Wyd. Nauk. PWN, Warszawa, p. 233 (in Polish).
Kondracki J., 2000, Geografia regionalna Polski (Regional
geography of Poland), Wyd. Nauk. PWN, Warszawa, p.
441 (in Polish).
Korycka A., 1991, Charakterystyka składu chemicznego
wody w jeziorach północnej Polski (Characteristics of
chemical composition of water in lakes of northern Poland), Rocz. Nauk. Rol., Ser H., 102(3): 7-112 (in Polish,
English summary).
Kozerski H., Behrendt H., Koehler J., 1999, The N and P budget of the shallow, flushed Lake Mueggelsee: retention, external and internal load, Hydrobiologia 408-409: 159-166.
Kudelska D., Cydzik D., Soszka H., 1983, System oceny
jakości jezior (System of lakes quality evaluation), Wyd.
IKŚ, Warszawa, p. 44 (in Polish).
Kudelska D., Cydzik D., Soszka H., 1994, Wytyczne monitoringu podstawowego jezior (Instructions of the elementary lake monitoring), Bibl. Monitoringu Środowiska,
Warszawa, p. 42 (in Polish).
Kufel L.,1998, Chlorophyll-nutrients-Secchi disc relationships in the Great Masurian Lakes (North-Eastern Poland), Pol. J. Ecol. 46(3): 327-337.
Kufel L., Kalinowska K., 1997, Metalimnetic gradients and
the vertical distribution of phosphorus in a eutrophic
lake, Arch. Hydrobiol. 140(3): 309-320.
Kufel I., Kufel L., 1999, Spatial variability and long-term
changes of the 47(3): 323-333.
Lossow K., 1998, Ochrona i rekultywacja jezior. Teoria a
praktyka (Protection and restoration of lakes. Theory and
practice), Idee Ekol. 13(7): 55-70 (in Polish).
Łopata M., 2005, Rekultywacja polimiktycznego jeziora
Głęboczek w Tucholi metodą inaktywacji fosforu (Restoration of the polimictic Lake Głęboczek in Tuchola by
phosphorus inactivation method), UW-M, Olsztyn, p 103
(dissertation) (in Polish).
Marszelewski W., 2005, Zmiany warunków abiotycznych w
jeziorach Polski północno-wschodniej (Changes of the
abiotic conditions in the lakes of north-east Poland),
Wyd. UMK, Toruń, p. 288 (in Polish, English summary).
Mikulski Z., 1966, Kształtowanie się działu wodnego na
Wielkich Jeziorach Mazurskich Evolution of watershed
line at Great Masurian Lakes), Prz. Geogr. 38: 381-392 (in
Polish, English summary).
Moss B., Barker T., Stephen D., Williams A.E., Balayla D.J.,
Beklioglu M., Carvalho L., 2005, Consequences of reduced nutrient loading on a lake system in a lowland
catchment: deviations from the norm?, Freshwater Biol.
50: 1687-1705.
Napiórkowska-Krzebietke A., 2004, Wieloletnie zmiany fitoplanktonu w jeziorach Niegocin, Mamry Północne i Kirsajty (Long-term changes of phytoplankton in lakes Niegocin, Mamry Północne, and Kirsajty), IRS, Olsztyn, p.
141 (dissertation) (in Polish).
Napiórkowska-Krzebietke A., Hutorowicz A., 2005, Longterm changes of phytoplankton in Lake Mamry Północne, Oceanol. Hydrobiol. Stud. 34(Suppl. 3): 217-228.
Napiórkowska-Krzebietke A., Hutorowicz A., 2006, Longterm changes of phytoplankton in Lake Niegocin, in
the Masurian Lake Region, Poland, Oceanol. Hydrobiol.
Stud. 35(3): 209-226.
59
Niewolak S., 1989, Badania mikrobiologiczne jeziora Niegocin (Microbiological investigations of Lake Niegocin),
Rocz. Nauk. Rol. Ser. H, 102 (1): 109-130.
Olszewski P., Paschalski J., 1959, Wstępna charakterystyka
limnologiczna niektórych jezior Pojezierza Mazurskiego
(Preliminary limnological characterization of some lakes
in the Mazurian Lake District), Zesz. Nauk. Wyższ. Szk.
Roln. Olszt. 4: 1-109 (in Polish, English summary).
Olszewski P., 1971a, Trofia i saprobia (Trophy and saproby),
Zesz. Nauk. WSR. Olszt., Seria C (suppl. 3): 5-14 (in Polish).
Olszewski P., 1971b, Jeziora trzeba chronić inaczej (Lakes
should be protected otherwise), Zesz. Nauk. Wyższ. Szk.
Roln. Olszt. 3: 13-18 (in Polish).
Patalas K., 1960a, Stosunki termiczne i tlenowe oraz przezroczystość wody w 44 jeziorach okolic Węgorzewa (Thermal and oxygen conditions and transparency of water in
44 lakes of Węgorzewo District), Rocz. Nauk Rol. B77(1):
105-222 (in Polish, English summary).
Patalas K., 1960b, Mieszanie wody jako czynnik określający
intensywność krążenia materii w różnych morfologicznie jeziorach okolic Węgorzewa (Mixing of water as the
factor defining intensity of food materials circulation in
morphologically different lakes of Węgorzewo Diostrict),
Rocz. Nauk Rol. B77(1): 223-242 (in Polish, English summary).
Patalas K., 1960c, Charakterystyka składu chemicznego wody
48 jezior okolic Węgorzewa (Characteristics of chemical
composition of water in 48 lakes of Węgorzewo District),
Rocz. Nauk Rol. B77(1): 243-297 (in Polish, English summary).
Perkins R.G., Underwood G.J.C., 2001, The potential for
phosphorus release across the sediment-water interface
in the eutrophic reservoir dosed with ferric sulphate, Wat.
Res. 35(6): 1399-1406.
Raike A., Pietilainen O.P., Rekolainen S., Kauppila P., Pitkanen H., Niemi J., Raateland A., Vuorenmaa J., 2003,
Trends of phosphorus, nitrogen and chlorophyll a concentrations in Finnish rivers and lakes in 1975-2000, Sci.
Total Environ. 310(1-3): 47-59.
Romeo J.R., Kagalou I., Imberger J., Hela D., Kotti M., Bartzokas A., Albanis T., Evmirides N., Karkabounas S., Papagiannis J., Bithava A., 2002, Seasonal water quality of shallow and eutrophic Lake Pamvotis, Greece: implications
for restoration, Hydrobiologia 474: 91-105.
Schindler D.W., 1977, Evolution of phosphorus limitation in
lakes, Science 195: 260-262.
Søndergaard M., Jensen J.P., Jeppesen E., 1999, Internal phosphorus loading in shallow Danish lakes, Hydrobiologia
408-409: 145-152.
Søndergaard M., Jensen J.P., Jeppesen E., 2001, Retention
and internal loading of phosphorus in shallow, eutrophic
lakes, Sci. World 1: 427-442.
Søndergaard M., Jensen J.P., Jeppesen E., Padisak J., Toth
L.G., Herodek S., Maberlyl S.C., Tatrai I., Voros L., 2003,
Role of sediment and internal loading of phosphorus in
shallow lakes, Hydrobiologia 506-509: 135-145.
60
Soszka H., Cydzik D., Kudelska D., 1979, Ocena stanu
czystości Wielkich Jezior Mazurskich (Assesment of the
water quality of the Great Masurian Lakes), Wyd. Akcydensowe, Warszawa, p. 67 (in Polish).
Spodniewska I., 1978, Phytoplankton as the indicator of lake
eutrophication. I. Summer situation in 34 Masurian lakes
in 1973, Ecol. Pol. 26: 53-70.
Spodniewska I., 1979, Phytoplankton as the indicator of lake
eutrophication. II. Summer situation in 25 Masurian
lakes in 1976, Ecol. Pol. 27: 481-496.
Standard methods for the examination of water and wastewater, 1992, Amm. Publ. Health Ass., New York, p. 1956.
Szczepański A., 1968, Scattering of light and visibility in water of different types of lakes, Pol. Arch. Hydrobiol. 15:
51-77.
Szczerbowski J., Korycka A., Zdanowski B.,1993, Zmiany
ichtiofauny w warunkach naturalnej i antropogenicznej
ewolucji jezior oraz rybackiego gospodarowania (Changes in fish fauna in the conditions of natural and anthropogenic evolution of lakes and fish farming), [in:] Dynowska I. (ed.) Przemiany stosunków wodnych w Polsce
w wyniku procesów naturalnych i antropogenicznych
(Transformations of water conditions in Poland as the
result of natural and anthropogenic processes), Wyd. UJ,
Kraków: 166-205 (in Polish).
Vollenweider R.A., 1968, Scientific fundamentals of the eutrophication of lakes and flowing waters, with particular
reference to nitrogen and phosphorus as factors in eutrophication, OECD Technical Report GP OE/515, OECD,
Paris, p. 250.
Vollenweider R.A., 1976, Advances in defining critical loading levels for phosphorus in lakes eutrophication, Mem.
Ist. Ital. Idrobiol. 33: 53-83.
Wróblewska H., 2002, Influence of pollution from point
sources on the purity of the Great Mazurian Lakes, Limnol. Rev. 2: 443-451.
Zachwieja J., 1975, Sesonal and several years’ fluctuations of
temperature, oxygen content and water visibility in the
Mamry lake complex, Ekol. Pol. 23(4): 587-601.
Zdanowski B., 1982, Variability of nitrogen and phosphorus
contents and lake eutrophication, Pol. Arch. Hydrobiol.
29(3-4): 541-597.
Zdanowski B., 1983, Ecological characteristics of lakes in
North-Eastern Poland versus their trophic gradient. III.
Chemistry of the water in 41 lakes, Ekol. Pol. 31(2): 287308.
Zdanowski B., Korycka A., Zachwieja J., 1984, Thermal and
oxygen conditions and the chemical composition of the
water in the Great Masurian Lakes, Ekol. Pol. 32(4): 651677.
Zdanowski B., Hutorowicz A., 1994, Salinity and trophy of
Great Masurian Lakes (Masurian Lakeland, Poland),
Ekol. Pol. 42(3-4): 317-331.

Change patterns in the trophic state of Lake Mamry Północne and

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