Structure of phototrophic communities in fresh lakes of the Baikal region under conditions of intensive eutrofication

We have studied freshwater lakes Dikoye and Kotokelskoye located in the coastal strip of Lake Baikal. Water blooming has previously been observed in the lakes. The lakes are classified as low-mineralized water bodies with alkaline pH values of water. According to the content of chlorophyll a, the lakes are assigned to the mesotrophic (Lake Kotokelskoye) and eutotrophic (Lake Dikoye) reservoir types. Proteobacteria, Cyanobacteria, Actinobacteria and Bacteroidetes are dominant phyla in the microbial community. Phototrophs are represented by cyanobacteria, green algae and diatoms. Potentially toxic species Microcystis aeruginosa and Leptolyngbya tenuis dominate among cyanobacteria in the lakes. Active growth of cyanobacteria in lake ecosystems is caused by changes in hydrological and physicochemical characteristics. It has revealed that the ecosystem of Lake Dikoye turned out to be more susceptible to seasonal fluctuations in physical and chemical parameters of the environment than the ecosystem of Lake Kotokelskoye, which is probably due to the shallowness, smaller area and lack of tributaries of the last.