Trends in the state of free-living ciliates community of lake Great Vasilyevskoye (Togliatti, Samara region) for twenty years

The current state of the community of free ciliates from urban hypertrophic lake Great Vasilyevskoe was investigated. The formation of species groups isn't due to spatial heterogeneity of habitats in the waters, but to seasonal phenomenon. Comparative analysis of the modern community of ciliates with the community of twenty-two years ago revealed trends in quantitative and structural parameters of ciliates community to confirm the increase of this pond trophic level. These are an increasing of the abundance, increasing the role of smaller species, changing trophic structure, reducing the contribution of mixotrophic ciliates, increasing the contribution of ciliates with greater index environment saprobity etc. Testing of anthropogenic eutrophication index (INEC) didn't give the expected results.