Composition of microbial communities as an indicator of the condition of water reservoirs artificially separated from the sea basins (based on the example of the Kislogubskaya tidal power plant bay, Barents sea)

Abstract

The Kislaya Bay currently refers to the water reservoirs formed as a result of the construction of the dam of the tidal power station (TPP) in the Russian Federation (1968). As a result of the reduction in the influence of tidal currents mixing the water column of the bay, the hydrological regime of the reservoir has changed. The reduction in water exchange led to the appearance of bottom stagnant waters deprived of oxygen, as well as hydrogen sulfide contamination. In the 90-s of the twentieth century, the operation of the Kislogubskaya TPP ceased and the flow regime was partially restored. In the winter season of 2024, we conducted microbiological and biogeochemical studies of the Kislaya Bay. It was shown that there was no hydrogen sulfide in the bottom water of the bay, and the processes of sulfate reduction, methane formation and methane oxidation were extremely low. At the same time, in the subsurface layer of sediment, bacteria and archaea were found that dominate the microbial communities of anoxic waters of meromictic reservoirs. We believe that with a stable exchange of water through the TPP dam, the composition of the microbial community of water and sediment will be restored. In case of negative developments, it is possible to predict the transformation of the bay into a reservoir with a community of microorganisms similar to meromictic reservoirs.