Reservoir: The Importance of Extracellular Organic Carbon Released by Phytoplankton
The spatial distribution and seasonal dynamics of heterotrophic bacterioplankton production were studied and the value of autochthonous sources of substrates for bacteria was evaluated in the pelagic zone of the meso-eutrophic Rybinsk Reservoir (the Upper Volga). During the vegetation period the bacterial production ranged from 32 to 1352 (on average 444 ± 44) mg C/(m2 day). The total input of organic carbon from the processes of extracellular production of phytoplankton, viral lysis of prokaryotic cells, and untidy feeding of protists provided 9-64 % (on average 32 ± 3 %) of the daily carbon demand of heterotrophic bacterioplankton.