[The biomass of microbial communities in different types of alluvial soils in the upper reach of the Selenga River estuary].

The biomass of several groups of microbial communities occurring in three types of alluvial soils in the upper Selenga River estuary near the village of Murzino, Kabansk raion, Buryat Republic was studied. The general tendency in the dynamics of the biomass of the dominant groups of microorganisms in drought summer-autumn period of 2005 was revealed. The bacterial complex predominated at the beginning of July; actinomycete and spore-fungal complexes, at the end of August; and spore-fungal and actinomycete complexes, at the beginning of October. In the alluvial sod soil, the actinomycete mycelium biomass was dominant in July, which was caused by more droughty conditions in this facies because it is located at a higher elevation above the river level than other facies.

[Patterns of formation of microbial communities of alluvial soils in the selenga estuary].

Microbial communities of alluvial soils in the facies on islands in the Selenga estuary and near Stepnoi Dvorets and Istomino Settlements were studied. The distribution of the CFU-dominant microorganisms (Bacillus and Pseudomonas + Arthrobacter) has been revealed in the studied island soils. In addition, actinomycetes Streptomyces were found among the dominants in soils of the near-terrace floodplain. The quantitative distribution of microorganisms across soil layers was demonstrated. The effect of ecological factors in formation of microbial communities on the islands and central floodplain regions was revealed.