Аннотация:The aim of this work is to study the taxonomic structure of the bacterial and archaeal communities in the soil profile of the Pymvashore tract. Pymvashore is located in the east of Bolshezemelskaya tundra (67° 09’N, 60° 51’E). Analysis of the biome of this “extreme ecosystem” reveals the response of the soil microbial communities to the additional input of the heat and the chemical elements, carried by the thermal waters. Vertical profile was obtained in the Pymvashore tract (coordinates: N 67° 09.740’E 060° 51.070’) on the steep slope of the north-eastern exposure (15 ° incline) between the hot springs under the herb meadow. Samples were selected for sequencing in four horizons (AY1 - 0-16 cm, AY2 - 16-33 cm, Bg - 33 - 60 cm, Cg - 60-110 cm) The analysis of the microbial communities reveals the extreme environmental conditions, existing for them in the investigated soil profile. The PCR data with real-time detection of the number of microorganisms shows that it is lower than the values typical for the tundra soils. Microbial diversity was studied by metagenomic methods. In constructing the library of amplicons and sequencing, a purified DNA preparation (10- 15 ng) was usedas a template in a PCR reaction. The chemical analysis of aqueous extract provides the evidence of a direct influence of the thermal waters on the upper layers of the soil: the lower layers are depleted in salt concentration and composition in comparison with the top. As evidenced by the result of the metagenomic analysis, the microbial community is dominated by bacteria from the phyla: Actinobacteria, Proteobacteria, Acidobacteria and other. However, with increasing depth, there is also an increase of the biodiversity and the proportion of the uncultured bacteria and the unidentified microorganisms. In The upper layers (5-20 cm) the proportion is relatively small and constitutes about 7% of all classes, while in the lower layers (40-65 cm), it increases to 32%