Microbiological characterization of cryogenic soils in the Kolymskaya lowland

The comparative study of microbial communities in different soils of the Ko lymskaya Lowland has been performed. The populations of procaryotic (bacter ia and actinomycetes) and eucaryotic (fungi and yeasts) microorganisms were discussed. The dependencies of microbial populations on zonal location, cr yoturbation intensity, texture, acidity, degree of hydromorphism, and redox conditions were revealed in different soil types. The study of the morphol ogical variability of cultures isolated showed that coryne-like bacteria we re predominant in the composition of the procaryotic complex. Most microbia l cenoses exhibited psychrophilic properties. The most oligotrophic microfl ora was found in sandy podbur, and the least oligotrophic microflora was ob served in tundra gley soil. Acid-tolerant bacteria were generally concentra ted in organogenic horizons; their content and proportion in cenoses of tai ga soils were larger than in tundra soils. The population of acid-tolerant procaryotes in all cases exceeded the population of eucaryotes counted on t he same media.