Wigry Lake: The Cradle of Polish Hydrobiology - a Century of Limnological Exploration

Wigry Lake, located in North-Eastern (NE) Poland, has a century-old history of limnological exploration and is an excellent place to assess the impact of catchment changes caused by urbanization on the functioning of a large, polymictic, and flow-through lake. The history of prewar limnological research, the course of hydrochemical effects of urbanization in the river flowing into the lake since the 1970s, and long-term changes in the functioning of Wigry Lake are presented. The collected archival and current results indicate that the hydrochemical type of the lake’s waters remained the same, and the inflow of river waters from the urban catchment strongly transformed the lake bay receiving the load. In the remaining part of the lake, the eutrophication load caused smaller changes because of a gradual reduction in the inflow of nutrients. Consequently, there was an increase in vertical differentiation of oxygen, algal biomass, and their structure. A significant share of supplying the lake with groundwater and the natural in-lake system of biotic and chemical regulations significantly reduced the effects of the eutrophication process. The existing lake biodiversity has been maintained, constituting a valuable element of the European NATURA 2000 system

Biomass, abundance and sensitivity to antibiotics and antimycotics of the fungi in the Vistula River with its main tributaries

Mycoplankton of Vistula River and its main tributaries biomass as well as the number and morphotype diversity was studied in summer and autumn 2011. Summer mycoplankton biomass was within the range of 0.2 – 0.5 μg/l, while in the autumn it was two times wider range (0.1 – 1.3μg/l). The number of fungi in river water most often did not exceed 1000 – 2000 CFU/ml. Fungi colonies isolated from rivers water were sensitive to the commonly used amphotericine B (10 μg) and gentamicin (10 μg). It seems to be plausible that aquatic fungi can acquire immunity to drugs as a result of horizontal transfer of a gene responsible for drug resistance or as an effect of antibiotics and antimycotics getting into the aquatic ecosystems from wastewaters

The variability of summer phytoplankton in different types of lakes in North East Poland (Suwałki Landscape Park)

This study describes summer phytoplankton communities in 27 lakes in the Suwałki 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

Long-term changes in the trophic state of Suwalki lakes – an analysis by means of indices based on abundance and composition of their rotifer fauna

Rotifer abundance and species composition in lakes of the Suwalki Landscape Park were studied in the years 1983–1985, 2009, 2012 and 2015. Rotifer trophic state indices (TSIROT) were used to assess changes in the trophic state of the studied lakes. In most lakes of the Suwalki Landscape Park, there were no changes in rotifer communities over the 25–32 year period to indicate a decline in trophy of the lakes. However, in lakes with the strongest decline in TSIROT values, the values of indicative parameters widely varied in 2015, which may indicate that the status of rotifer communities in the lakes may be dependent on non-trophic factors