PHYTOPLANKTON TAXONOMIC STRUCTURE AS INDICATOR OF THE TROPHIC STATUS AND ECOLOGICAL STATE OF UVILDI LAKE, RUSSIA

The phytoplanktonic algal flora of Uvildi Lake was studied during June -July 2014 by analysing samples taken from 5 sampling stations in north-western and north-eastern parts of like. Identified taxa (38) of the phytoplanktonic community are as follows: 13 Bacillariophyta, 9 Cyanophyta, 9 Chlorophyta, 4 Euglenophyta, 2 Chrysophyta, 1 Dinophyta. The dominants were diatom algae. They represented 42% of the total number of species. The blue-greens were represented in the majority by Anabaena lemmermannii, Microcystis aeruginosa and Anabaena flosaquae. The most abundant diatoms were the most numerous representatives by Fragilaria crotonensis and Asterionella formosa. Chlorophyta were presented significantly poorer (8 %), the most numerous representative is Coenococcus planctonicus. Other divisions were represented by markedly fewer species. We recorded 38 planktonic algal species, including 35 species that could be used as indicators of saprobity. The saprobic index for each year of the study was in the range of values from 1.63 to 2.35 which characterizes the lake as satisfactorily clean. The values of the taxonomic resolution obtained in the study sites indicate the mezotrophic status of the lake.