Trends in the Phytoplankton Variability of the Selected Polish Lakes

Abstract

The directional changes of phytoplankton in Polish lakes were presented to show some tendency concerning the total biomass, composition, and biodiversity as related to environmental variables. The selected lakes were analyzed concerning various types of antropopressure, e.g., relatively low, medium, and huge human impact including sewage inflow history, different hydrological regime nature as natural phenomenon of flow-through lakes and as a consequence of artificial including into water-cooling system with short retention time, and different restoration actions (biomanipulation and artificial aeration). Smaller biomass and more varied structure of phytoplankton (co-dominated by Bacillariophyta, Cryptophyta, Miozoa, and Cyanobacteria) were typical of the PEG Model for mesotrophic or even oligotrophic temperate lakes with lower trophy level. On the contrary, a large biomass with Cyanobacteria domination in summer was typical in more eutrophied lakes. The prominent dominants were primarily chroococcalean Microcystis aeruginosa and M. wesenbergii and filamentous Planktolyngbya limnetica, Pseudanabaena limnetica, Limnothrix redekei, and Planktothrix agardhii. Species richness and values of biodiversity index were usually higher in more eutrophied lakes than in mesotrophic lakes. The overall relationships of phytoplankton groups with environmental variables indicated that water transparency in less eutrophied lakes while water temperature and nutrient concentrations in more eutrophied lakes induced phytoplankton growth.