Microbial communities of bottom sediments of Alas Lakes of Central Yakutia as indicators of agricultural load

Alas (thermokarst) basins with lakes are unique landscapes of the cryolithozone, widespread in the territory of Central Yakutia and traditionally used by the indigenous population for household needs (as sources of water, pastures and hayfields). In addition, alases are of great climatic importance, since they are active sources of greenhouse gas emissions. Microbial communities play a key role in the transformation of buried and modern organic matter entering alas ecosystems as a result of the impact of climatic and anthropogenic factors. However, microbiological studies of such ecosystems are extremely rare. This paper characterizes the phylogenetic diversity of microbial communities in the bottom sediments of three alas lakes in Central Yakutia – Tyungyulyu, Taby and Kharyyalakh. It was found that anaerobic chemoheterotrophic prokaryotes predominate in the sediments, but at the same time a large diversity of uncultured microorganisms with unknown metabolism was revealed. It is shown that microbial communities of bottom sediments can be indicators of agricultural load experienced by lakes. Microorganisms of the methane cycle were highly represented in the lake with the lowest anthropogenic load.