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1

Urea in lake ecosystem: the origin, concentration and distribution in relation to trophic state of The Great Mazurian Lakes (Poland)

100%

Siuda W., Kiersztyn B.

Polish Journal of Ecology

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2015

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tom 63

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nr 1

The distribution, concentrations and origin of urea were studied in surface and profundal waters of meso-eutrophic and highly eutrophic parts of The Great Mazurian Lake System (GMLS) during spring — autumn period. Urea concentrations varied from 0.25 µM in surface layer to 3.36 µM in profundal zone of studied lakes and were in the range of concentrations noted in other non-polluted freshwater habitats. In the photic zone of lakes of GMLS Urea N made up to 10 % the total DON pool and often exceeded 2-3 times of NH₄-N concentrations. Pattern of changes in urea concentrations observed during three-years study excludes external urea input and suggests supplementation of lake waters with this compounds by phytoplankton decomposition processes. Generally, urea concentrations were negatively correlated with the trophic state index calculated from “algal” as well as from “bacterial” determinants. However, more detailed analysis showed that the relationships between production and assimilation of urea by various plankton components as well as the ecological role of this compound in meso- and eutrophic lakes could be different.

2

The abiotic conditions of a deltaic lake ecosystem [on the example of the Druzno Lake catchment]

100%

Cieslinski R.

Journal of Water and Land Development

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2003

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nr 07

3

The usefulness of zooplankton as lake ecosystem indicators: Rotifer Trophic State Index

84%

Ejsmont-Karabin J.

Polish Journal of Ecology

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2012

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tom 60

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nr 2

Eutrophication is still one of the most important, world – wide problems of surface waters. During last decades there is the increasing demand for effective methods of monitoring systems based on biotic indices. For practical application, the monitoring tools must satisfy certain requirements: (1) sampling should be quick and easy; (2) indices should be straightforward to calculate. The aim of the study was to test the usefulness of rotifer abundance and species composition as indicators of trophic state of lakes. Data on rotifer densities and taxonomic composition were collected in 41 dimictic and 33 polymictic lakes situated in northeastern Poland. The samples were taken once a year, during the summer stagnation period at 1 m intervals from the surface to the bottom of the epilimnion layer in thermally stratified lakes and from the surface to the bottom of shallow lakes. The data were used to estimate the relationship between the rotifer community structure and the indices of trophic state of lakes (TSI), like concentration of chlorophyll a and Secchi’s disc visibility, (as the estimator of suspended particulate material in the water) calculated according to Carlson (1977) and widely used recently. The estimations were made separately for dimictic and polymictic lakes. However, regressions for the relationships between the trophic state of lakes based on mean values for Secchi’s disc (TSISD ) and chlorophyll a content (TSICHL ) and rotifer indices for both groups of lakes, usually were not different. Thus the same regression equations may be used for both dimictic and polymictic lakes. The following formulas for rotifer TSI index (TSIROT) were found: (1) rotifer numbers (N, ind. L-1): TSIROT1 = 5.38 Ln(N) + 19.28; (2) total biomass of rotifer community (B, mg w.wt. L-1): TSIROT2 = 5.63 Ln(B) + 64.47; (3) percentage of bacterivores in total rotifer numbers (BAC, %): TSIROT3 = 0.23 BAC+ 44.30; (4) ratio of biomass to numbers (B:N, mg w.wt. ind.-1): TSIROT4 = 3.85 (B:N)-0.318; (5) percentage of the tecta form in the population of Keratella cochlearis (TECTA, %): TSIROT5 = 0.198 TECTA + 48.8 for dimictic lakes and TSIROT5 = 0.144 TECTA + 54.8 for polymictic ones; (6) contribution of species which indicate high trophic state in the indicatory group’s numbers (IHT, %): TSIROT6 = 0.203 IHT + 40.0. It was assumed that the lakes with a TSIROT under 45 are mesotrophic, those with a TSIROT value of 45–55 are meso-eutrophic, 55–65 - eutrophic and those with a TSIROT above 65 - hypertrophic. The formulas may be useful in preparing similar indices for lakes in central and northern Europe.

4

Role of psammon microinvertebrates in phosphorus cycling in hydroarenal of an eutrophic lake

84%

Ejsmont-Karabin J., Gorelysheva Z., Kalinowska K., Rybak J. I.

Polish Journal of Ecology

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2012

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tom 60

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nr 3

Inorganic phosphorus released from littoral bottom sediments plays significant role in phosphorus budget of a whole ecosystem. An aim of the study was to assess a role of small invertebrates in phosphorus remineralization in hydroarenal (See Fig.1 in Preface). Hydropsammon organisms (i.e. bacteria, algae, ciliates, rotifers and crustaceans) living in a layer of submerged sands along the edge of a lake (=hydroarenal) were studied in psammolittoral of the deep, eutrophic Lake Mikołajskie (North-eastern Poland) in 2005. Sampling cores were taken at a station 1.5 m from water’s edge once or twice a month since April until October 2005. Each time three samples were taken: 5-cm thick water layer (AWL – adjacent water layer), 0.5-cm thick layer of water and sand from the transitory level (EPIH – epihydroarenal) and 2-cm thick slice of sand (ENDOH – endohydroarenal). The rate of phosphorus excretion was calculated using the appropriate regression equations expressing the relation between individual weight of organism and P excretion adjusted to the ambient temperature. Phosphorus remineralization by the psammon community (calculated for all ciliates, rotifers and crustaceans) was ca. 10 times higher than the maximum rate noted in lake pelagial. The most important role in the process was played by small ciliates, and in periods of high remineralization rate – by small cladocerans. Omnivores, feeding mostly on bacteria and small algae, played the most important role in all three studied layers, especially in periods of the highest rate of P remineralization, thus all kinds of food were used and mineralized. Predators do not seem to play significant role in P remineralization. In hydroarenal significant role seems to be played by processes involved in microbial loop. This suggestion is supported by strong domination of ciliates, main consumers of nanoflagellates, in the process of P remineralization. It seems that phytopsammon and psammic bacteria demands for phosphorus cannot be satisfied merely through the in situ remineralization by microinvertebrates.

5

Co-occurrence of two stoneworts of reverse ecological spectra in the same lake ecosystem. Habitat requirements of Chara delicatula Agardh and Chara globularis Thuillier in the context of bioindication

84%

Pelechaty M., Pukacz A., Pelechata A.

Polish Journal of Environmental Studies

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2004

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tom 13

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nr 5

Regarding their distribution in lakes, Chara delicatula and Chara globularis are considered species of different or even opposite ecological requirements. C. delicatula is usually reported from oligotrophic lakes, but C. globularis from more fertile ones. Within Poland, both species rarely build extensive stands in the same ecosystem. The present study was carried out in a stratified, mid-forest lake in midwestern Poland where C. delicatula had not been found earlier. Based on the physical-chemical properties and analyses of phytoplankton, a transitional, meso-eutrophic status of the lake was stated. In the group of 15 more frequent macrophyte species, C. delicatula and C. globularis were among plants predominating the lake’s macrovegetation. Both stoneworts built separate patches as well as contributed to other macrophyte assemblages. Growing under the same light and trophic conditions, the species revealed differences in ecological optima in relation to the depth of occurrence and bottom slope. The results are discussed in the context of the species identity: are C. delicatula and C. globularis separate species or forms within the same taxon?

6

Analysis of the spatial and seasonal variability if inorganic species of arsenic, antimony and selenium in a shallow lake subjected to moderate anthropopressure

84%

Pelechaty M., Pelechata A., Niedzielski P., Siepak M., Sobczynski T.

Polish Journal of Environmental Studies

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2004

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tom 13

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nr 2

This study was aimed at recognizing the levels of arsenic, antimony and selenium concentrations in different zones of the lake ecosystem. Total content as well as inorganic species of the studied metalloids were considered. Shallow Lake Jarosławieckie (Wielkopolski National Park) was chosen for the study reported. Water samples were collected in different macrophyte communities of the phytolittoral and in the middle of the lake in early spring and mid-summer 2002. Total concentrations of all studied metalloids in samples collected in summer were lower than in those collected in spring but not all studied mineral species of As, Sb and Se followed the same pattern of changes. Despite seasonal changeability the lack of significant spatial differentiation in the concentrations of the elements studied at the peak of the vegetation season, in particular no differences in their concentrations between the sites in the bulk water in the middle of the lake and the sites in the plant communities was stated. This finding might testify to the fact that the effect of vegetation on the concentration of the elements studied is limited.

7

Trophic status of lake water evaluated using phytoplankton community structure - change after two decades

84%

Szelag-Wasielewska E.

Polish Journal of Environmental Studies

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2006

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tom 15

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nr 1

Phytoplankton composition and biomass were studied in a small suburban lake within the city of Poznań (western Poland) on the basis of water samples taken in epilimnion. Results obtained in 1999 were compared with the first study period, of 1978. In the first period, 100 phytoplankton taxa were found and diatoms were the largest group of species (29% of all taxa), while in the second period 117 phytoplankton taxa were recorded and green algae dominated (50%). The mean phytoplankton biomass increased nearly 2-fold over the two decades and the trophic state index was higher in 1999. Picophytoplankton, whose seasonal fluctuations were analyzed only in 1999, accounted for 0.6% to 31.5% (mean 12.8%) of total phytoplankton biomass.

8

Preliminary investigations of relative polarity of dissolved humic substances in select lakes of the Elk District, Poland

67%

Glazewski R., Wojcik I.

Polish Journal of Environmental Studies

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2009

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tom 18

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nr 4

599-606

The reported study describes the separation of humic substances (HS) dissolved in surface waters into hydrophilic and hydrophobic fractions with the SPE method onto StrataX (Phenomenex) columns. The separated fractions were analyzed with the HPLC-C18 (Merck column) method for relative polarity of humic (HA) and fulvic (FA) acids in the samples. Analyses were carried out on samples collected from 7 lakes constituting two cascade systems located in the same catchment of the Ełk River. During HPLC assays, an effect of size exclusion (SE) was observed, especially for the hydrophilic fraction. The HPLC analyses enabled us to demonstrate that in both hydrological systems the hydrophilic fraction contained mainly molecules with molecular weights exceeding 1,000Da and of practically equal relative polarity. Only in system II (five lakes) was the hydrophobic fraction strongly diversified quantitatively as well as in terms of molecular weight and polarity between the samples. Results of analysis show that this system was subject to a strong anthropogenic impact.

9

The role of emergent macrophytes in nutrient cycling in Lake Niepruszewskie (Western Poland)

67%

Lawniczak A. E.

Oceanological and Hydrobiological Studies

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2010

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tom 39

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nr 2

10

The suitability of zooplankton as lake ecosystem indicator: crustacean trophic state index

67%

Ejsmont-Karabin J., Karabin A.

Polish Journal of Ecology

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2013

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tom 61

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nr 3

Industrial processes and the use of fertilizers are the main causes for the rapid eutrophication of lakes. Different indices, both chemical and biological, may be used to assess a level and a rate of the eutrophication process. Zooplankton indices can be among them, as zooplankton community structure is determined primarily by the physical and chemical environment and modified by biological interactions, i.e. predation and interspecific competition for food resources. Among biological indices of trophic state of lake, those based on densities and structure of crustacean communities seem to respond weaker. There are, however, patterns of crustacean communities connected with trophic state of lakes. Thus, an increase in trophic state causes: (1) an increase in the total numbers of crustaceans; (2) an increase in the total biomass of Cyclopoida; (3) an increase in the contribution of the biomass of Cyclopidae to the total crustacean biomass; (4) an increase in the ratio of the biomass of Cyclopoida to the biomass of Cladocera; (5) a decrease in the average body weight of Crustacea; (6) an increase in the ratio of Cladocera to Calanoida numbers; (7) an increase in the ratio of Cyclopoida to Calanoida numbers; (8) an increase in the dominance of species indicative of high trophy (Mesocyclops leuckartii, Thermocyclops oithonoides, Diaphanosoma brachyurum, Chydorus sphaericus, Bosmina (Eubosmina) coregoni thersites) in the numbers of all indicative species. Crustacean zooplankton was sampled at the deepest place in a lake at 1 m intervals from the surface to the bottom of epilimnion layer, and then samples were pooled together for the layer. Samples were taken once a year, during the summer stagnation. The material was collected from a total of 41 dimictic and 33 polymictic lakes within Masurian Lake District, Iława Lake District and Lubawa Upland. Among above-mentioned indices, six were the best correlated with trophic state of lakes. Below are formulas which enable to assess trophic state of lakes regardless of their mixis type (TSICR) from parameters of abundance and structure of crustacean communities: (1) TSICR1 = 25.5 N⁰‧¹⁴² (R² = 0.32), where TSI = trophic state index; N = numbers (ind. l⁻¹); (2) TSICR2 = 57.6 B⁰‧⁰⁸¹ (R² = 0.37), where B = biomass (mg w.wt. l⁻¹); (3) TSICR3 = 40.9 CB⁰‧⁰⁹⁷ (R² = 0.35), where CB = percentage of biomass of Cyclopoida in the total biomass of Crustacea (%); (4) TSICR4 = 58.3 (CY/CL)⁰‧⁰⁷¹ (R² = 0.30), where CY/ CL = ratio of the Cyclopoida biomass to the biomass of Cladocera (%); (5) TSICR5 = 5.08 Ln (CY/CA) + 46.6 (R² = 0.37), where CY/CA = ratio of Cyclopoida numbers to the numbers of Calanoida; (the relationship covering exclusively dimictic lakes); (6) TSICR6 = 43.8 e⁰‧⁰⁰⁴ (IHT) (R² = 0.30), where IHT = percentage of species indicative of high trophy in the indicative group’s numbers. It was assumed that the lakes with a TSICR under 45 are mesotrophic, those with a TSICR value of 45–55 are meso-eutrophic, those with a TSICR value of 55–65 – eutrophic and those with a TSICR above 65 – hypertrophic. Although crustacean indices of trophic state of lakes seem to be less useful than other biological indices, they may be recommended in assessing the quality of lake waters.

11

Zoobenthos diversity in six lakes of Polesie Lubelskie region (Eastern Poland)

67%

Tarkowska-Kukuryk M.

Teka Komisji Ochrony i Kształtowania Środowiska Przyrodniczego

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2004

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tom 01

12

Recent changes in large and shallow Lake Peipsi ( Estonia/Russia): causes and consequences

67%

Haberman J., Haldna M., Laugaste R., Blank K.

Polish Journal of Ecology

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2010

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tom 58

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nr 4

The large and shallow lowland lakes constitute a distinctive type of lake ecosystem, because of their polymixis, frequent resuspension of bottom sediments and internal nutrient loading, high turbidity and usually high productivity and eutrophication rate. Lake Peipsi is one of the largest lake in Europe, its area is 3555 km² and mean depth is 7.1 m. The study results for the vegetation seasons (May-October) obtained for the decade 1997–2008 allow to evaluate the long-term changes in the functioning of its ecosystem in terms of dynamics of phyto- and zooplankton and nutrient content in a lake. Lake Peipsi consists of three different parts: the northern, the largest and deepest one is eutrophic L. Peipsi s.s. (sensu stricto), the southernmost part is hypertrophic L. Pihkva, connected with L. Peipsi s.s. by the river-like L. Lämmijärv. The decrease in nutrient loading to L. Peipsi observed in the early 1990s was brought about by social changes (collapse of Soviet type agriculture) rather than by the purification of point-pollution sources. In the northern part, Lake Peipsi s.s., the content of both nitrogen and phosphorus was stabilized, while the increase in phosphorus in the water of L. Pihkva was evident. The resistance of the three lake parts to external nutrient loading is different. It seems that the ecosystem of the southern lake part (L. Pihkva) is losing its resilience. The disturbance of the ecosystem is most likely caused by the fact that the slight trend of re-oligotrophication beginning in the early 1990s was reversed in the mid-1990s due to increasing P loading. The share of cyanobacteria in phytoplankton biomass increased from 20% to 60% in L. Peipsi s.s., and from 30% to 90% in the southern parts of the lake in the summer months. The lake was characterized by massive cyanobacterial blooms. Potentially toxic genera (Microcystis, Aphanizomenon, Anabaena, Gloeotrichia) dominated, and the quantity of microcystins in the lake was relatively large. The biomass of phytoplankton increased whereas that of all zooplankton groups – cladocerans, copepods and rotifers – decreased. The most essential decline affected rotifers: their abundance was about 60% lower in 2001–2008 than in the 1990s. The biomass of copepods decreased almost 50% and that of cladocerans 34%. In parallel with changes in plankton, the fish composition of L. Peipsi was characterized by sharp decline of planktivorous smelt (Osmerus eperlanus eperlanus m. spirinchus Pallas) and vendace (Coregonus albula (L). The most likely causes of the changes seem to be mainly the anthropogenic P input, decreasing N:P ratio, cyanobacterial toxins, and changes in ichthyocoenosis. Our data from last decade demonstrate a kind of disturbance in the ecosystem of the lake as compared to the second half of last century. The disturbance of the ecosystem is most likely caused by the fact that the slight trend of re-oligotrophication beginning in the early 1990s was reversed in the mid-1990s due to increasing P loading from southern part of lake watershed.

13

Seasonal changes quality and quantity structure of periphytic ciliates in trophically different lakes

67%

Mieczan T.

Teka Komisji Ochrony i Kształtowania Środowiska Przyrodniczego

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2004

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tom 01

14

Usługi ekosystemów jeziornych - klasyfikacja, waloryzacja, zastosowania

67%

Szkaradkiewicz M., Kazak J., Sabura K., Oleszek J.

Acta Scientiarum Polonorum. Formatio Circumiectus

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2014

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tom 13

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nr 3

Koncepcja usług ekosystemów jest rozwijającym się polem badawczym. Koncepcja ta wywodzi się z dokonań dyscypliny, jaką jest ekonomia środowiska, czyli łączenia aspektów środowiskowych z ekonomicznymi. Usługi ekosystemów mogą być również postrzegane jako inne podejście do pojęcia kapitału naturalnego, który wraz z kapitałem ekonomicznym i społecznym oraz ich wzajemnymi relacjami tworzy podwaliny koncepcji zrównoważonego rozwoju. Najczęściej przytaczana definicja usług ekosystemowych została wypracowana w ramach projektu Milenijnej Oceny Ekosystemów (MA) i zakłada, że są to korzyści, jakie ludzie czerpią z ekosystemów. W 2005 roku w ramach MA przyjęto podział usług ekosystemów na podstawowe, zaopatrujące, regulujące i kulturowe. Na podstawie wyników prac zespołu dokonującego Milenijnej Oceny Ekosystemów oraz Agencji Ochrony Środowiska w Stanach Zjednoczonych w artykule dokonano podziału usług ekosystemów jeziornych. Do otrzymanej klasyfikacji zaproponowano metody wyceny oraz zastosowania koncepcji usług ekosystemów.

15

Total organic carbon as a new index for monitoring trophic states in lakes

67%

Dunalska J. A.

Oceanological and Hydrobiological Studies

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2011

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tom 40

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nr 2

16

The bottom sediments of Lake Uzarzewskie – a phosphorus source or sink?

67%

Kowalczewska-Madura K., Goldyn R., Dondajewska R.

Oceanological and Hydrobiological Studies

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2010

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tom 39

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nr 3

17

Present-day changes in the morphology of the shore zone in the conditions of heavy tourist use: the case of Lake Czarne (upper Parseta catchment)

67%

Cichon M.

Quaestiones Geographicae

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2011

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tom 30

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nr 3

18

Winter versus summer blooming of phytoplankton in a shallow lake: effect of hypertrophic conditions

67%

Toporowska M., Pawlik-Skowronska B., Krupa D., Kornijow R.

Polish Journal of Ecology

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2010

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tom 58

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nr 1

The comparison of species richness, abundance and diversity of phytoplankton blooms, which developed both in winter and summer seasons as an effect of lake hypertrophy, was the aim of this study. In the ice-covered lake (0.30 mg PO₄ -P L⁻¹, 1.35 mg NH₄ -N L⁻¹; TSISD = 64; TSIchl = 93), the algal bloom, responsible for high concentration of dissolved oxygen in water, consisted mainly of the centric diatom Stephanodiscus minutulus (3.9 × 10⁷ ind. L⁻¹) accompanied by Limnothrix redekei (Cyanobacteria), Koliella longiseta (Chlorophyceae), > 1.1 × 10⁶ ind. L⁻¹ each, as well as Mallomonas sp. (Chrysophyceae) and Monoraphidium komarkovae (Chlorophyceae), >5.0 × 10⁵ ind. L⁻¹ each. The toxic cyanobacterium Planktothrix agardhii of extremely long trichomes (up to 0.93 mm) and potentially toxic dinoflagellate Peridinium aciculiferum f. inerme occurred also in high numbers (1.9 × 10⁵ ind. L⁻¹ and 7.7 × 10⁴ ind. L⁻¹, respectively). In summer (0.05 mg PO₄ -P L⁻¹; 0.42 mg NH₄ -N L⁻¹; TSISD = 78; TSIchl = 102), the phytoplankton bloom consisted of P. agardhii (average total abundance 49.4 × 10⁶ ind. L⁻¹) and ten other taxa of Cyanobacteria, Bacillariophyceae, Chlorophyceae and Cryptophyceae (average total abundance 17.9 × 10⁶ ind. L⁻¹). The total phytoplankton abundance was 1.5 times higher in summer than in winter and the total biomass of the most abundant species was approximately 4 times higher in warm (139.8 mg L⁻¹) than in cold season (32.5 mg L⁻¹). The values of the Shannon-Weaver diversity index were very low, however, over 2 times higher in summer (0.60) than in winter (0.31). The obtained results revealed that in the hypertrophic lake the very high nutrient concentrations (especially NH₄ -N and PO₄ -P), found both in winter and summer, were responsible for year-long mass development of phytoplankton. The winter phytoplankton was composed mainly of very small centric diatoms, whereas summer blooms were created by filamentous cyanobacteria (mainly Oscillatoriales; 98%).

19

Spatial and temporal variability of TOC concentrations in a shallow and eutrophicated lake ecosystem [Lake Jaroslawieckie, Wielkopolski National Park, Western Poland]

67%

Pelechaty M., Pelechata A., Niedzielski P.

Polish Journal of Environmental Studies

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2003

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tom 12

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nr 5

The aim of this study was to characterize the spatial and temporal variability of total organic carbon concentrations in a shallow, eutrophic lake (Lake Jarosławieckie, the Wielkopolski National Park, midwestern Poland) against the background of lake habitat heterogeneity. The interrelations between TOC and chlorophyll a in different studied sites (in macrophyte communities as well as in open water sections) were also taken into account. In November 2000, March, May, June and July 2001, water samples were collected in two transects along and across the lake traversing macrophyte communities of the phytolittoral zonation (7 sites) and reaching the open water zone (mid-lake, 3 sites) and, additionally, in a site close to a beach attracting local inhabitants and tourists. Statistical analyses revealed significant temporal differentiation and reverse patterns of changes of both TOC and chlorophyll a concentrations in the studied lake, whereas the spatial one was not significant. No correlations between both parameters were found. The results of cluster analyses suggest macrophyte vegetation and its seasonal changes in development as the main factor to influence TOC concentrations.

20

Two approaches to lake-naturalness determination - a case study from four mid-forest Polish lakes

67%

Pelechaty M., Gabka M.

Polish Journal of Environmental Studies

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2003

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tom 12

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nr 4

This study aimed at evaluate the ecological states of four protected, mid-forest lakes located in mid-western Poland. Two means of evaluation were used and compared: biodiversity (expressed by phytocoe-notic diversity of macrohydrophyte vegetation) and habitat diversity (resulting from abiotic conditions and biota activity). The first method was based on the type and number of plant associations present in the studied lakes. The contribution of naturally and anthropogenically induced plant assemblages to lake vegetation was considered. The other method concerned morphometric, mictic and trophic features of the lakes and their water purity classes. The study results, especially a large number of plant assemblages and natural character of vegetation, evidenced a high degree of naturalness of all the reservoirs. However, re-sults obtained with the use of both methods were to a certain degree inconsistent. With respect to the type of catchment and mid-forest location as well as still limited anthropopressure, the phytocoenotic diversity more clearly differentiated the reservoirs and more accurately reflected their ecological status than the habi-tat diversity whose use - especially as the only or main method - seems to be rather limited.

Ograniczanie wyników

Urea in lake ecosystem: the origin, concentration and distribution in relation to trophic state of The Great Mazurian Lakes (Poland)

The abiotic conditions of a deltaic lake ecosystem [on the example of the Druzno Lake catchment]

The usefulness of zooplankton as lake ecosystem indicators: Rotifer Trophic State Index

Role of psammon microinvertebrates in phosphorus cycling in hydroarenal of an eutrophic lake

Co-occurrence of two stoneworts of reverse ecological spectra in the same lake ecosystem. Habitat requirements of Chara delicatula Agardh and Chara globularis Thuillier in the context of bioindication

Analysis of the spatial and seasonal variability if inorganic species of arsenic, antimony and selenium in a shallow lake subjected to moderate anthropopressure

Trophic status of lake water evaluated using phytoplankton community structure - change after two decades

Preliminary investigations of relative polarity of dissolved humic substances in select lakes of the Elk District, Poland

The role of emergent macrophytes in nutrient cycling in Lake Niepruszewskie (Western Poland)

The suitability of zooplankton as lake ecosystem indicator: crustacean trophic state index

Zoobenthos diversity in six lakes of Polesie Lubelskie region (Eastern Poland)

Recent changes in large and shallow Lake Peipsi ( Estonia/Russia): causes and consequences

Seasonal changes quality and quantity structure of periphytic ciliates in trophically different lakes

Usługi ekosystemów jeziornych - klasyfikacja, waloryzacja, zastosowania

Total organic carbon as a new index for monitoring trophic states in lakes

The bottom sediments of Lake Uzarzewskie – a phosphorus source or sink?

Present-day changes in the morphology of the shore zone in the conditions of heavy tourist use: the case of Lake Czarne (upper Parseta catchment)

Winter versus summer blooming of phytoplankton in a shallow lake: effect of hypertrophic conditions

Spatial and temporal variability of TOC concentrations in a shallow and eutrophicated lake ecosystem [Lake Jaroslawieckie, Wielkopolski National Park, Western Poland]

Two approaches to lake-naturalness determination - a case study from four mid-forest Polish lakes