Assessing the Abundance, Biomass, and Production of Heterotrophic Bacteria in Upper Volga Reservoirs

Two reservoirs in the Upper Volga were studied to determine the abundance, biomass, and production of planktonic, epiphyte, and benthos bacterial communities and to assess their contribution to the formation of the total abundance and productivity of bacteria. The abundance and production of heterotrophic bacteria per 1 cm 3 of bottom sediments were 10–10 2 times greater than those in epibioses of higher aquatic plants and 10 3 –10 4 times greater than those in water mass. In the mesoeutrophic Rybinsk Reservoir and eutrophic Ivan’kovo Reservoir, bacteriobenthos accounts for 90.4 and 98.8% of the total biomass and 95.8 and 99.5% of the total production of heterotrophic bacteria; bacterioplankton, for 9.55 and 1.19% of biomass and 4.12 and 0.45% of production; and bacterioepiphyton, for 0.05 and 0.03% of biomass and 0.03 and 0.02% of production. The obtained data demonstrate the important role of benthic bacterial communities in the Upper Volga reservoirs.