The paper deals with microbiological and hydrochemical studies of the Kyiv section of the Kaniv Reservoir over 2022-2024. The abundance of bacterioplankton ranged from 3.9 to 14.9106 cells/cm3, portion of bacteria with damaged cytoplasmic membranes was 10.5-87.5 of the total numbers. The abundance of eutrophic and oligotrophic bacteria amounted to 30.0-475.8103 and 2.1-226.7103 cells/cm3, respectively. The studied microbiological and hydrochemical parameters were characterized in seasonal, spatial, and interannual aspects. Seasonal fluctuations in bacterioplankton development depended on temperature regime, water level, dissolved organic matter quality, and anthropogenic pressure, including that caused by hostilities. Certain elements of the hydrological regime, hydrochemical, and microbiological parameters significantly correlated (p 0.03). In the spatial distribution, similar fluctuations of the average abundance of bacterial communities was observed in the bays and river section; however, the ranges of fluctuations differed being broader in the bays. Interannual changes of the bacterial abundance in water were comparable, except for the dead bacteria portion, which gradually decreased about 1.5 times during 2022-2024. The abundance of the sanitary indicatory bacteria and opportunistic microorganisms indicated that the water quality of the Kyiv section of the Kaniv Reservoir did not meet the sanitary-ecological safety standards at all studied sites. According to the ecological classification of the surface water quality based on the abundance of eutrophic bacteria, the Kyiv section of the Kaniv Reservoir was classified as "very bad" corresponding to the V quality class. The observed changes in ammonium nitrogen, phosphate phosphorus concentrations, and organic matter content (in terms of CODMn and CODCr) resulted from the intensified impact of natural and anthropogenic factors, as well as unstable operational regime of the Kyiv hydroelectric power plant.
Starosyla et al. (Thu,) studied this question.