Soil Microbial Activity and Functional Diversity in Primeval Beech Forests

Abstract

Virgin forests are unique ecosystems, which can be used as etalon for basic biocoenotic investigation. Soil microorganisms are very sensitive reagents on influence of biotical factors, and at the same time are the active producers of phytotoxic and phytostimulating exometabolites. Studies of soil microbiota were conducted in virgin beech forests of Shyrokoluzhansky massif of the Carpathian Biosphere Reserve. It was found the ratio and the number of different ecological-trophic groups of soil microorganisms changes with altitude. So the number of ammonificators with increasing of altitude above sea level was reduced. The soil at altitude of 1,100 meters above sea level was characterized by minimum content of organotrophes -1.22 × 106 (CFU-colony forming units/1g.a.d.s.). At the altitude of 500 meters content of ammonificators increased at six times and was 7.07 × 106 CFU/1g.a.d.s., which indicates to accumulation of the soil organic matter. Similar changes occurred with the number of bacteria which are using mineral forms of nitrogen for their nutrition. Their maximum quantity (4.32 × 106 CFU/1g.a.d.s.) was in the soil of biotope disposed at altitude of 500 meters above sea level. Fluctuations in the number of soil micromycetes of virgin forest ecosystems have not been as significant as the bacterial microbiota (within 17 × 103-28 × 103 CFU/1g.a.d.s.). Among a wide spectrum of bacterial microbiota were isolated strains with high phytostimulating action.