The development of mixotrophic ciliates of waterbodies from Bottom, Central Volga and Kama river as indicator of special living conditions

39 species of mixotrophic ciliates from plankton of different reservoirs of Central, Bottom Volga and Kama (reservoirs, inflows, large and small lakes with various type of hashing of water column and of trophic level, "sulphidic" flowing waterbodies, "marsh" lakes, etc.) are registered. The heterogeneity of their structure, the maximum contribution to abundance in the stratified reservoirs with sulphidic hypolimnion and the maximum contribution to biomass in small gumic lakes is shown. Development trends and ecological preferences for the mixotrophic ciliates vary depending on their adaptive strategy.The species composition of mixotrophic ciliates and their horizontal and vertical allocation is defined by specific abiotic and biotic conditions in a reservoir and poorly depends on zonal factors.