Rechkalov V.V., Golubok O.V., Shimanskaya M.L.
VERTICAL DISTRIBUTION OF ROTIFERS IN LAKES WITH DIFFERENT TROPHIC STATUS ^{[№ 10 ' 2015]}
The work is devoted to studying rotifers plankton in different trophic status lakes of Chelyabinsk region. Among the investigated reservoirs are oligotrophic lakes Uvildy and Turgoyak, mesotrophic lakes Big Kisegach and Big Miassovo as well as hypertrophic lake Small Terenkul. Rotifers plancton was cought in aquatic layers with the Jedi; it was confined to the period of the summer thermal stratification. It were found 13 species of rotifer, most of which is eurybiontic. Representatives of four most important species are confined to the waters of the trophic class. The greatest number of rotifers — 9.9 thousand copies/m³ were observed in hypertrophic Lake M. Terenkul, they were accounted for 37 % of the total zooplankton. In other lakes rotifers plankton was less developed, his strength was from 0.7 to 4.0 thousand copies/m³, while the share in the total number of zooplankton does not exceed 15 %. A comparative analysis of the vertical distribution of rotifers plankton was produced. The maximum number of rotifers oligotrophic lakes is observed in the upper layer to the horizon of 6 m, while 12 m deep fixed local maximum in the bottom layer rotifers met in small amounts or absent. The mesotrophic lakes representatives of this taxonomic group were concentrated at the surface or in the depths metalimnion ranging from 4 to 9 meters. The bottom layers were also sparsely populated. Feature distribution of rotifers hypertrophic lake S. Terenkul was that in addition to the near-surface high dense cluster of aquatic organisms were found in the bottom layer and the adjacent region of the hypolimnion. The role of individual species in the formation of the total picture of the distribution of rotifers plankton was observed and discussed. It was made the conclusion about the prospects of using the species composition, abundance and performance features of the vertical distribution of rotifers to monitor anthropogenic eutrophication of lake ecosystems.