Quantification of Mineralizable Pool of Organic Matter in Tundra Cryosols of Kolyma Lowland

The cryogenic mass-exchange processes affect the content and distribution of organic matter in Cryosol profiles enriching the mineral horizons with organic matter. It has been shown that the mineralization capacity of organic materials in Cryosols is low even under optimum conditions of temperature and moisture. Despite the significant variation in the microbial biomass content, the general pattern of its distribution in the profile with a maximum in organic horizons and a minimum in mineral horizons is preserved in all studied profiles. The fraction of the microbial biomass carbon (Cmb) in the total organic carbon is less than 1%. The microbial respiration quotient (Qr) varies from <0.1 to 0.3. The most significant influence on the microbial biomass and changes in its respiration activity in the profiles of Cryosols is recorded for the contents of total organic carbon (TOC) and total nitrogen (TN) and for the soil porosity.