Structure and diversity of soil microbial communities in the permafrost peatlands in the north- west of Bolshezemelskaya tundra

He analysis of microbial complexes of permafrost peat soil of the forest-tundra flat permafrost peatlands was made. The study object is located in the north- western part of Bolshezemelskaya tundra, within the above-floodplain terrace of the valley of the lower reaches of the Pechora river (latitude 67° 39'10.7'' North, longitude 53° 23'24.9'' East). Microbial communities were studied by a complex of classical and present-day molecular genetic methods. Molecular genetic studies were performed on the basis of PCR-based diagnostics of amplificated fragments of 16S rRNA genes of bacteria and archaea. As the study result, the limits of variation of total microbial biomass (1.7-15.3 mg / g of substrate) in peat permafrost soil of permafrost peatlands were established. Microbial biomass in the profile of peat soil is distributed unevenly. Its maximum concentration (value) is confined to the middle part of the profile (10-20 cm), which correlates with the maximal content of bacterial cells, spore and mycelium of fungi. In the frozen peat layers, the value of microbial biomass is comparable to that of the active layers of the peat soil profile. The fungal mycelium plays the basic role (97.3-99.8%) in the formation of microbial biomass structure, bacteria account for an insignificant part (0.2-2.7%). In the upper part of the active layer (0-30 cm) bacteria cells with an intact cell membrane (58-84%) prevail, in the supra permafrost horizons (30-55 cm) and the upper layers of the permafrost (55-90%)bacterial cells with damaged cell membrane (56-66%) dominate. The prokaryotic complex of the active layer of peat soil of the forest-tundra permafrost peat- lands is represented mainly by phyla of bacteria Acidobacteria, Actinobacteria, Bacteroidetes, Planctomycetes, Proteo-bacteria and Verrucomicrobia, lower (frozen) - Acidobacteria, Firmicutes, Thau-ma-rchaeota. The high representation of the spore-forming bacteria of the phylum Firmicutes indirectly indicates that most part of the microbial complex of the frozen peat is represented by microorganisms capable of forming low tem-perature resistant resting forms.