Phototrophic microflora of dystrophic Lake Sęczek, Masuria, Poland

Microflora of cyanobacteria and algae of small forest dystrophic Lake Sęczek located in the Masurian Lake District, NE Poland, was investigated in 2012 and 2013. A total of 16 genera with 7 species of cyanobacteria and 56 genera with 74 species, 6 varietas and forms of algae were determined. Most of them represented commonly occurring microorganisms of slightly acidic waters, but some of them are considered rare, i.e. the oscillatorian cyanobacterium Katagnymene accurata Geitler (for the first time found in Poland), and green algae Coenochloris sphagnicola Hindák, Mucidosphaerium sphagnale (Hindák) C. Bock, Pröschold et Krienitz, Closterium navicula (Bréb.) Lütkem., and Cosmarium cf. aphaerosporum var. corribense (W. et G.S. West) Krieger et Gerloff., which are described in more detail. As regards the species diversity, the plankton of the lake was rather species-poor in contrast to the algal communities in the Sphagnum littoral.