Phytoplankton of the lake Palanskoye: taxonomy, ecology, dynamics of quantitative characteristics
The plankton algae community of Palanskoye Lake consists of plankton cosmopolitan, cold-water, typically freshwater, alkali-prefer species. Among species able to indicate organic pollution the species of naturally pure waters predominate. Only a small group in the pool of 80 species identified in plankton is structure-forming. The species contributing maximally to the abundance are diatom Aulacoseira subarctica (42%) and blue-green algae (31%) of Microcystis genera. The main part in the phytoplankton biomass (59%) consists of Aulacoseira subarctica. The species to contribute to the biomass less are Tabellaria flocculosa, Stephanodiscus alpinus, Asterionella formosa, Cyclotella tripartita, Synedra ulna, Synedra cf. actinastroides and Diatoma elongatum. The part of Microcystis is miserable. The intraseasonal dynamics of the total abundance of phytoplankton typically demonstrates a consequent increase of the abundance from June to September suddenly changing into decrease in October. Although there is no observed a clear answer of phytoplankton biomass to the income of phosphorous from fish carcasses or mineral fertilizers, the long-term dynamics of phytoplankton abundance and biomass exhibits the tendency of growth since the second half of the 1990th to 2001-2005, which probably can be reckoned as an effect of the phosphorous accumulation in this lake system.