Microbiocenosis of Cryofrost Soils in the South of the Vitim Plateau

The microbial communities in soils of cryomorphoses in the south of the Vitim Plateau have been studied. The objects of study were gley cryoturbated chernozems and humus-quasi-gley carbonated soils. In the course of the study, experimental sites with pronounced cryogenic phenomena were selected. The intensity of microbiological activity was determined by the carbon content of microbial biomass, the number of microorganisms in the dominant groups of microbial communities. Determination of the number of microorganisms in soils was carried out by direct microscopy, which makes it possible to carry out a more accurate count of bacteria in the soil, taking into account adsorbed cells. Cells were preliminarily desorbed on an ultrasonic disperser. The carbon of microbial biomass was determined by the rehydration method. Data were obtained characterizing the direction and intensity of microbiological processes along the horizons of soil profiles of heaving mounds and thermokarst depressions. The number of microorganisms and the dominant groups of bacterial communities of soils formed under the conditions of the ultracontinental climate of Buryatia and relatively close-lying permafrost are presented. It was revealed that bacterial microflora predominates in the soils of heaving mounds and thermokarst depressions. The intra-profile heterogeneity in the distribution of soil microorganisms indicates that, as a habitat, the soil is strongly differentiated in all directions. This differentiation along the vertical of heaving mound and thermokarst depression was reflected in the concept of soil horizons as special ecological niches and the possibility of using microbiological indications of heaving and subsidence occurring during heaving.