Influence of Temperature and Water Level on the Phytoplankton in the Estuarine Zone of the Rybinsk Reservoir Tributary

The structural parameters of phytoplankton in the estuarine region of a small tributary (Ild River) were studied in 2009–2011 and compared with the adjacent sections of the free-flowing section of the river and the pelagic zone of the Rybinsk Reservoir. Phytoplankton of the mouth estuarine region of the Ild River is characterized by high floristic and specific richness, biomass and coenotic diversity. With an increase in water temperature and a decrease in the water level in the reservoir, an increase in floristic richness, biomass, and the degree of similarity of the ratio of large taxonomic groups of algal communities of ecotone and border zones were observed in the mouth area of the tributary.