Human activity and anthropopression play key roles in contaminating aquatic environments with microplastics (MPs). The lakes of northeastern Poland provide a wide range of freshwater ecosystems ...differing in morphology, hydrology and ecology. In this study, we investigate 30 lakes during summer stagnation, considering their varying levels of anthropogenization of the catchment area and taking into account increased tourist activity. MPs were found in each of the studied lakes in the range from 0.27 MPs/L to 1.57 MPs/L, and the average value was 0.78 ± 0.42 MPs/L. The features of the MPs were evaluated, including size, form and color (most frequent: 4–5 mm (35.0 %); fragments (36.7 %); blue (30.6 %), respectively). Gradual accumulation of MPs has been observed in the lakes that comprise the hydrological sequence. The amount of sewage produced by wastewater treatment plants was considered in the study area. Statistically significant differences were found between lakes with different surface areas and shoreline lengths, where lakes with the highest and smallest values were notably more polluted with MPs than lakes in the medium range (F = 34.64, p < .0001 and F = 5.96, p < .01, respectively). The study presents an easy-to-obtain shoreline urbanization index (SUI) that is particularly useful for lakes with heavily transformed catchments in terms of hydrology. A significant correlation between the MP concentration and SUI, reflecting the degree of direct catchment anthropopression (r = +0.4282; p < .05), was observed. The analysis of the human impact on shoreline conversions and development should also pique the interest of other researchers as a potential indicator of MP pollution.
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•Microplastics pollution was studied during summer stagnation in 30 different lakes.•Fragments, fibers and films were the dominant forms of the collected MP•The most morphometric lakes parameters are not important in terms of MP abundance.•The accumulation of MP in the hydrological sequence of the lakes was observed.•The shoreline urbanization index may be an important indicator of MP pollution.
Zebra mussels (ZM), Dreissena polymorpha (Pallas, 1771), are one of the most aggressive invasive species. ZM have a strong bidirectional impact on phytoplankton because of their high nutrient ...excretion rates and high grazing pressure. Furthermore, the interactions between excretion and selective grazing are related to the trophic status of a waterbody and could cause unpredictable changes in phytoplankton. We performed three types of experiments: (i) bottom-up where we measured ZM excretion rates; (ii) top-down where we analyzed the effects of ZM on phytoplankton taxonomic structure via grazing in different trophic conditions; (iii) mesocosm experiment where we estimated the combined top-down and bottom-up effects of ZM on phytoplankton assemblages under different trophic conditions. Our first experiment confirmed high excretion rates of dissolved nutrients (PO43− and NH4+) and dissolved organic carbon (DOC) by ZM. The other experiments revealed selective grazing by ZM, where diatoms were mostly selectively rejected, while green algae were preferred. In the top-down experiment, ZM decreased the total biomass of phytoplankton, while in mesocosm experiments where top-down and bottom-up controls acted simultaneously, we observed increased phytoplankton biomass mainly through increases in filamentous green algae. Our experiments show that ZM can influence phytoplankton through a combination of bottom-up and top-down effects that vary with trophic state.
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•Zebra mussel (ZM) has a strong bidirectional impact on phytoplankton species structure.•Bottom-up experiment revealed high excretion rates of DOC, PO43− and NH4+ by ZM.•Selective grazing of ZM – diatoms were rejected and green algae were preferred.•Combined experiment revealed that bottom-up effect surpasses top-down (grazing).
The Supraśl River is a stable water ecosystem in North-Eastern Poland. This is indicated by the flow rate over many years, as well as the water quality monitored for years. Despite this, there are ...periods of oxygen deficiency in the water, causing massive fish kills. Our research shows that climate change resulting in an increase in the frequency of hydro-meteorological extremes may contribute to negative processes taking place in aquatic ecosystems. On the example of Supraśl Water System (SWS), we present an analysis of the phenomenon of suspension caused by the underground inflow, supplying the surface waters with a significant load of organic matter. The accelerated decomposition of peat formations in the Supraśl River catchment after heavy rains makes it easier for organic matter to penetrate into the aquatic ecosystem. Intensive flushing of valley and river bed sediments during summer floods has a particularly negative impact on the ecosystem of inland waters. If there are organic sediments on the bottom, their re-suspension is very dangerous. Then there is the immediate demand for oxygen, which can lead to deoxygenation of the water. Although this is a natural process, alarm and monitoring procedures should be established and countermeasures sought to respond in time and prevent mass fish kills.
This study describes changes in the trophic status of 12 lakes within Suwałki Landscape Park (SLP). All of the trophic classifications of the lakes were based on the trophic continuum division. ...Trophic status was determined by means of multiparameter indices using several diverse criteria. In this study, the assessment of the trophic status of lakes included water quality; abundance and biomass of bacterioplankton, phytoplankton, and zooplankton; and primary production of phytoplankton. The Carlson trophic state index (TSI) describes the level of water fertility and indicated the dominance of moderately eutrophic waters. Lakes Perty, Jeglówek, and Hańcza have a trophic status that indicates mesotrophy (TSI <50). The trophic status of the studied lakes was determined based on the bacterial abundance and clearly showed a lack of oligotrophic lakes in SLP. Based on the number of bacteria, only Lake Szurpiły can be classified as β-mesotrophic, whereas Lake Linówek can be characterized as hypertrophic with some features typical for humic waters. The greatest value of gross primary production was observed in Lake Linówek (126.4 mg C/m³/h). The phytoplankton trophy index varied from 1.59 to 2.28, and its highest value, which indicated eutrophy, was determined for Lake Udziejek. In the case of Lakes Hańcza, Szurpiły, Perty, Jeglówek, and Kojle, the index ranged from 1.25 to 1.74, which indicated mesotrophy. The majority of the lakes were classified as mesoeutrophic (1.75–2.24). The highest trophic status was assessed for lakes with a marked dominance of cyanobacteria (Lake Przechodnie, Lake Krajwelek, Lake Udziejek, and Lake Pogorzałek), which is commonly recognized as an indicator of high trophic status. Considering all of the indices of trophic status, the analysis of rotifer community structure indicates that the studied group of lakes is mesoeutrophic or eutrophic. The values of crustacean zooplankton indices indicated that the trophic status of the studied lakes was close to that determined using a TSI. The parameters of zooplankton abundance and species structure allowed for the observance of changes in the tropic levels of lakes, which are difficult to detect by a chemical assay alone.
Natural groundwater outflows are very sensitive to changes in the environment. In the era of changing climate and progressive anthropogenic activity, they often disappear, retreat, and water quality ...deteriorates. Inefficient sources in lowland areas are the most vulnerable to these processes. In 2021, we conducted an inventory of natural groundwater outflows in the Biebrza Valley. Most of the existing outflows are non-concentrated outflows (exudations, linear leakages, fens). The outflow of several outflows exceeded 5 dm3·s−1. Their distribution within the Biebrza Basin is uneven. We identified the largest concentration of linear seepages on the right bank of the lower Biebrza basin near the village of Ruś. The most common types in the BNP are di- and tri-ionic waters, characteristic of lowland areas of Poland. The increase in nitrogen and phosphorus compounds in the spring water indicates the impact of the developing agricultural activity (cattle breeding). The increase in DOC concentration may reflect changing hydro-meteorological conditions (droughts and torrential rains). The values of most parameters in spring water were lower than in shallow groundwater. This gives a better picture of the quality of shallow groundwater. The physical and chemical characteristics of natural groundwater outflows in the BNP fall within the hydro-chemical background of the waters of the first aquifer in this area.
Wetlands play a crucial role in the hydrological cycle, controlling flood generation, dry season flows, and water quality. This emphasizes the part of the Biebrzański National Park in protecting ...naturally valuable habitats. Our research aimed to assess (quantitatively and qualitatively) the state of groundwater affecting the condition of wetlands. The analyses carried out in 2021 were compared with the results of hydrological and hydro-chemical mapping of the first groundwater level from 1998.
Quaternary formations serve as the main groundwater reservoir in the Biebrza Valley. These formations consist of pore water located at shallow depths, usually ranging from 0.5 to 10.95 meters. Most often, the first aquifer occurred at 1–3 meters deep. No significant reduction was observed when comparing the current water table levels with data from 1998. More than half of the surveyed dug wells are used for economic purposes. The Biebrza River is an outflow for shallow groundwater, as the hydroizohypses system indicates.
The shallow groundwater resources in the Biebrzański National Park include mainly low and medium mineralization waters. A significant increase in the concentration of nitrogen compounds (NH4+-N, NO2−-N, and NO3–N), phosphorus, and dissolved organic carbon was recorded. This trend is evident in areas with intensive cattle breeding and is associated with excessive use of manure and slurry. The research confirmed the mosaic nature of the chemical composition observed in 1998 and the wide range of variability of the chemical properties of shallow groundwater.
Our research provides valuable insights into the uneven distribution of groundwater copepods in the lowland river valley ecosystem using an integrative taxonomy approach. The study was conducted in ...101 wells in the Biebrza River Valley (northeastern Poland), which is one of the largest and best-preserved lowland rivers in Europe. It stands out for its exceptional biodiversity and pristine natural landscapes. Groundwater copepods were found in 49 of the 101 analyzed wells. We identified ten species of Copepoda and eight species of Cladocera. The most frequent copepods were Diacyclops bicuspidatus, Diacyclops crassicaudis, Canthocamptus staphylinus, Paracyclops cf. fimbriatus, Diacyclops bisetosus, and Eucyclops serrulatus. The aforementioned species were categorized as stygophiles, and no stygobionts were detected. Our findings suggest that the groundwater Copepoda community in this region is relatively stable and composed mostly of stygophiles along with stygoxenes. We did not find any significant impact of environmental parameters or different aquifers on the distribution of copepods, suggesting a patchy distribution of groundwater copepods in the lowland river valley. The relatively high presence of stygoxenes suggests that the exchange of organisms between surface water and groundwater plays a vital role in maintaining the diversity of microcrustaceans in lowland river valleys. Our study contributes to filling the knowledge gap regarding groundwater fauna in lowland Europe, particularly in areas affected by Pleistocene glaciations.
Summer field research and chemical analyses in 2015 provided the basis for the presentation of the trophic status of waters of 28 lakes of the Suwalki Landscape Park in NE Poland, located in the ...catchment of the River Neman, in the Natura 2000 area - Ostoja Jeleniewska. Lakes Hancza and Szurpily are currently mesotrophic ecosystems. The remaining lakes are moderately eutrophic, while four lakes in the group, in addition to anaerobic hypolimnion, have infertile epilimnion similar to that of mesotrophic lakes. Lake Hancza shows considerable multiannual dynamics of water fertility, periodically reaching a status approximate to eutrophy. In Lake Szurpily and the majority of smaller lakes of the Suwalki Landscape Park, reduced precipitation in 2015 resulted in an inconsiderable decrease in trophic status. The lakes are under the strong influence of their catchment area, as confirmed by statistically significant correlations between TSI and the Ohle and Schindler ratios. Lakes Kluczysko and Kopane currently remain the most fertile lakes in the Park. Unless rapidly developing cattle breeding leads to excessive fertilisation of waters in the catchment, the forecasted variability of weather conditions during global climate transformations will lead to fluctuations in the fertility of the majority of the analysed lakes at the threshold of meso- and eutrophy. A hypothesis is also stated regarding the considerable role of groundwater alimentation and short retention time in the maintenance of higher than average resources of silica in limnic waters.
This study describes summer phytoplankton communities in 27 lakes in the Suwalki Landscape Park (SLP) using in situ fluorescence methods. Low chlorophyll-a concentrations were noted in most of the ...studied lakes, particularly in the deepest lakes with highest surface area. Green algae, diatoms and cryptophyta were dominant components of lake phytoplankton. Higher chlorophyll-a concentrations in the shallow or more eutrophicated lakes were connected with an increase of cyanobacteria and cryptophyta concentrations as well as with a decrease in the share of diatoms inphytoplankton structure. Vertical distribution of phytoplankton in stratified lakes revealed the presence of deep chlorophyll layers just below the thermocline where the maximum concentrations of phytoplankton were up to 15 times higher than in the epilimnion zone. The deepest maximum concentration of phytoplankton was noted at a depth of 16.5 metres in Lake Jeglówek. In some lakes two or three significant increases of phytoplankton concentration in the vertical profile were observed, caused by intensive development of different algae groups.
Research carried out from 2007 to 2011 showed that a tested semi-natural water system with a diverse catchment (peat, peat-mineral and mineral) has a very varied quality of water, as evidenced by a ...the large range of conductivity (174–828 μS/cm) and pH (6.34–9.92). Natural lake parts of the semi-natural water system were similar to the artificial parts in terms of physico-chemical parameters, as evidenced by the lack of statistically significant differences between the water quality in both of these ecosystems. Taking into account the quality of various types of water in this semi-natural system, it can be seen that the river waters differed significantly (
p
< 0.001) in concentrations of biogenic elements (nitrogen, phosphorus) from another type of ecosystems. In addition, rivers poor in organic matter (TOC < 10.0 mg/L) which directly supplied the water system contributed to higher values of many tested parameters (EC, pH, TC, TN, SO
4
2−
or Cl
−
) in waters of the canal. In contrast, rivers with high values of concentrations of organic matter (TOC > 10.0 mg/L) contributed to a decline in values of those parameters. Moreover, lake waters within the tested semi-natural water system showed a “cleansing” function, because they caused a decrease in conductivity, pH or the concentration of carbon, total nitrogen, sulphate(VI) and chloride in waters of the canal.
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