Seasonal Dynamics of the Structural and Functional Organization of Heterotrophic Bacterioplankton in the Mouth Area of the Small Il’d River

We have studied the seasonal dynamics of the structural and functional characteristics of heterotrophic bacterioplankton in the mouth area of the small Il’d River (inflowing into the Rybinsk Reservoir) and sections of bordering water bodies—the rivers themselves and reservoirs during the growing seasons of 2007 and 2009–2011. The abundance, biomass, and production of planktonic bacteria varied greatly, reaching maximum values in the mouth area of the inflow. Statistical processing of the results confirmed the dependence of the number of bacteria on organic matter in spring and early summer and on water temperature in summer. In terms of the abundance and production of bacterioplankton, the mouth area of the inflow is characterized by the manifestation of an edge effect, most pronounced in its frontal zone.