Quantitative distribution of microbial biomass in the soil profile of a high-mountain grassy ecosystem.

The soil microbiota of a grassy ecosystem in the subalpine belt of the Rila Mountain National Park showed greater amounts of fungal biomass. This remained relatively constant throughout the months of sampling while bacterial biomass was a dynamic value fluctuating within a wide range. The two groups of microorganisms also differed in their in-depth distribution in the soil profile: the bacterial biomass was relatively homogeneously distributed while the fungal biomass gradually decreased with depth. Good correlation between the amount of biomass and the values of some abiotic factors of the environment was shown by correlation analysis in a "warm" period of investigation; no distinct correlation between microbial biomass and environmental factors was observed in a "cold" period.