To assess the ecological status of water bodies, phytoplankton development indicators are widely used. The article deals with the use of microalgae in the assessment of water quality using the example of the Barskoye Lake. Collection and processing of hydrobiological material were carried out in the autumn of 2016 by standard methods. Phytoplankton is represented by 76 taxa below the genus belonging to 7 divisions: Chlorophyta (30), Bacillariophyta (16), Cyanophyta/Cyanoprocaryota (12), Euglenorhyta (7), Chrysorhyta (5), Сryptоphyta (3), Dinophyta (3).
