The state of aquatic ecosystem according to hydrochemical and hydrobiological indicators of the Kizhi skerries area of Lake Onego during the ice period

For the first time during theice-сovered period, comprehensive hydrochemical and hydrobiological studies were conducted in the area of Kizhi Island on Lake Onego. During winter, average concentration of total phosphorus was 7 μg/l, which corresponds to oligotrophic water types. The concentrations of iron, manganese and pollutants (including petroleum products and synthetic surfactants) did not exceed the maximum permitted levels for fishery water bodies. The results of hydrochemical analysis suggest that the water quality in the Kizhi skerries is satisfactory. The study area is characterized as oligotrophic with elements of β-mesotrophy determined by hydrobiological indicators (bacteria, phytoplankton, zooplankton and macrozoobenthos).