Microbial communities of thermal lake Umkhei (Baikal rift zone) in the zone of discharge of groundwater
E. V. Lavrentyeva1,2, T. G. Banzaraktsaeva1, A. A. Radnagurueva1, S. P. Buryukhaev1, V. B. Dambaev1, O. A. Baturina3, L. P. Kozyreva1, D. D. Barkhutova1
1Institute of General and Experimental Biology of SB RAS, Ulan-Ude, Russia
2Buryat State University, Ulan-Ude, Russia
3Institute of Chemical Biology and Fundamental Medicine of SB RAS, Novosibirsk, Russia
Keywords: зона разгрузки подземных вод, термальное озеро, таксономическое разнообразие микробного сообщества, функциональная активность, Байкальская рифтовая зона, zone of discharge of groundwater, thermal lake, taxonomic diversity of the microbial community, functional activity, Baikal rift zone
Abstract
The diversity and functional activity of the microbial community in the zone of discharge of groundwater of the thermal lake Umkhei (Barguzinskaya depression, Baikal rift zone) was examined. It is shown that the lake waters are thermal hydrocarbonate-sulphate-sodium type and belong to the Kuldur type of mineral waters. Lake sediments were distinguished by higher temperatures and greater microelements saturation. A comparative analysis of the species richness of the microbial community of water and bottom sediments showed high indices of diversity in all layers of sediments, the diversity in water was lower. Analysis of taxonomic diversity revealed the domination of representatives of Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Chloroflexi in the community of water and bottom sediments. The presence of bacteria with various metabolic pathways of substance and energy transformation, both in production and in destruction processes, was established. Sequences belonging to the genus Hydrogenophaga of the β- Proteobacteria class, which is an indicator of the deep geochemical processes of hydrogen formation, were found in the lower layers of sediments. The functional activity was studied and the rates of microbial processes of photosynthesis, dark assimilation of CO2, sulfate reduction and methanogenesis were determined. It is established that the main part of the organic matter production in water occurs as a result of the activity of chemolithoautotroph prokaryotes. The producers of the microbial community synthesize organic matter by using volcanogenic carbon dioxide enriched in the ᵟ13C heavy isotope. Analysis of the terminal processes rates shows that the main process is sulfate reduction.
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