Dynamics of Biological Activity and Water-Soluble Organic Matter in Tundra Soils on Slopes of Different Aspects in the Khibiny Mountains

摘要

The dynamics of the content and properties of water-soluble organic matter and the biological activity of soils of dwarf-shrub heath and graminoid meadow of alpine tundra on slopes of different aspects are estimated. The variation of most of the studied parameters during the growing season is revealed, which confirms the importance of dynamic observations in assessing the role of soils in changing environment. Soils on the southwestern slope are characterized by higher mean daily temperatures and lower water contents throughout the entire growing season. Despite this, slope aspect does not affect the content of water-soluble organic matter and the potential respiratory activity of soil microorganisms. At the same time, under warmer and drier conditions, the organic matter of alpine tundra soils is less resistant to microbiological transformation. The natural gradient of soil temperature and moisture does not significantly affect the efficiency of using carbon sources and the overall functioning of microbial communities. Based on the data obtained, it is predicted that the adaptation of the soil microbial community to a gradual rise in temperatures in the Subarctic region should proceed without a sharp increase in the rate of mineralization of soil organic matter by microorganisms.