Многолетние изменения фитопланктона Рыбинского водохранилища (Волга, Россия)

Abstract

Long-term studies of the structural characteristics of phytoplankton in the Rybinsk Reservoir in the conditions of eutrophication and climate change have been carried out in 1950th to 2010th . The study revealed the following phenomena: (a) an increase in total biomass of phytoplankton and relative biomass (%) of blue-green algae (cyanobacteria) and cryptomonads; (b) increase in species richness and abundance of golden algae and non-hetetrocystous cyanobacteria; (c) increase in total species richness per samples; (d) increase in abundance of small-sized species; (e) elevated magnitude of summer peak in the seasonal dynamics of biomass; (f) a decrease in number of diazotrophic species; (g) decline of coenosis diversity, evenness and ratio of minimum to maximum biomass as a measure of ecosystem stability; (h) change in the ratio of morpho-functional groups of phytoplankton in a direction: B → D + C → S1 → Y, i. e. from species characteristic of mesotrophic, well mixed waters, to the species associated with high trophic level waters, tolerant to light deficiency and capable for phagotrophy