Effect of Climatic Fluctuations on the Structure and Functioning of Ecosystems of Continental Water Bodies

Climatic fluctuations are among the most important factors that cause changes in terrestrial and aquatic ecosystems. This review considers the principal mechanisms of the influence of climate changes on the structure and functioning of ecosystems of water bodies and shows the need to take these mechanisms into account when developing strategies for conserving the biological resources of aquatic ecosystems. Climatic fluctuations affect aquatic ecosystems through changes in temperature, surface runoff of nutrients and other substances and their ratios, the intensity of water mixing during the circulation period, and other mechanisms. Additional nutrients received in rainy periods from the catchment area and directly with precipitation stimulate the growth of primary producers and cause the risk of the further eutrophication of water bodies. An increase in temperature promotes the growth of potentially toxic phytoplankton species and exacerbates the problem of green tides, the massive development of multicellular algae in the coastal zone. Organic substances coming from the catchment area during wet periods stimulate a microbial loop in aquatic ecosystems. In shallow lakes, climate fluctuations can cause changes in food webs and the ecological regime. Climate-induced changes in the composition of producer communities often weaken pelagic–benthic relationships in aquatic ecosystems. In some cases, climate changes have contributed to the invasions of alien species. The natural dynamics of ecosystems affected by climate fluctuations deserves close attention and requires the development of special adaptive management of aquatic biological resources. In some cases, it is necessary to take more severe measures for the protection and restoration of water bodies, which would take into account adverse changes in natural factors.