Soil algae and cyanoprokaryota of steppe communities of the Baikal basin

The article presents the results of studies of herbaceous plant communities in the Baikal basin, with the significant participation of the diazotrophic cyanoprokaryota Nostoc commune. The territory of the investigation is located at the foot of the Primorskiy range. There are developed mountain, typical steppe, and meadow communities on chestnut soils. A high content of carbonates was found in the soils, and the pH of the upper horizons varied from slightly acidic to alkaline. The composition of algae and cyanoprokaryota species living in and on soils has been revealed. In total, in steppe and meadow communities we identified 71 species from five divisions: Cyanoprokaryota – 27, Bacillariophyta – 4, Ochrophyta – 3, Chlorophyta – 34, and Charophyta – 3. 58 species have been found in steppe communities, 40 in meadow. A predominance of cyanoprokaryota and green algae was noted. The composition of the studied phototrophic species in steppe communities differed significantly from that of the meadow. In steppe communities Nostoc commune formed macroscopic colonies, and its biomass production was low (about 2 g/m2) comparable to that of a number of Asia arid territories. The N. commune biomass formation was higher on the mountain slope and at its foot, where higher density of soil composition, lower field humidity, as well as an increased content of calcium, magnesium, and sodium was found in soils. The N. commune biomass was reduced in the site at a distance from the mountain slope where the content of the above elements was lower. The regular sampling of macrocolonies had a negative impact on their renewal.