Succession of Microbial Community in Gray Forest Soil during the Decomposition of Different Organic Compounds

In a model laboratory experiment on gray forest soil, the succession of microbial communities during the decomposition of proteins, lipids, and polysaccharides was studied. Proteins were mineralized during the first three months; active decomposition of lipids started two months after the beginning of the experiment. Differences in the functional diversity of microbial communities during the succession were revealed using the method of multisubstrate testing of respiration activity. Microbial respiratory responses to introduction of nitrogen-containing compounds (amino acids) were the highest in variants with decomposition of nitrogen-free compounds and low in protein variants. The ratio of respiratory responses of microbial communities to introduction of carboxylic acids to that of amino acids characterized the nitrogen supply in the soil. This parameter may be useful for reconstruction of initial presence of organic materials in various archaeological contexts.