Phytoplankton in the Littoral and Pelagial Zones of the Rybinsk Reservoir in Years with Different Temperature and Water Level Regimes
The features of the loristic composition and dynamics of biomass of phytoplankton in shallow and deep areas of the Volga reach in Rybinsk Reservoir have been studied during the years with different thermal and level regimes (2009-2011). The floristic diversity and biomass of phytoplankton increased with the decrease in depth. The increase in water temperature at low water level stimulated phytoplankton vegetation in the pelagial zone, and the decrease in biomass in the littoral, while high diversity of algocenoses was recorded irrespective of a bitope. The contribution of filamentous algae and cyanoprokaryotes to the biomass increased in the shallow littoral, and in the open part of the reservoir the biomass of mixotrophic lagellates decreased. Their abundance as well as the the abundance of zignematales increased with a decreasing depth.