Microorganisms of Al-Fe-humus podzols under lichen pine forests affected by aerotechnogenic pollution

The spatial distribution and seasonal dynamics of microorganisms in sandy A l-Fe-humus podzols under lichen pine stands were studied. The high concentr ation of microorganisms in mineral horizons is assumed to be due to the inp ut of nutrient substrate with descending soil solutions. Fungi are shown to be the edificators in communities. However, fungi are more susceptible to changes in the quality of the substrate than prokaryotic microorganisms. So il pollution by heavy metals deteriorates the quality of soil nutritive sub strate: it becomes enriched in heavy metal compounds and impoverished in or ganic matter and nutrients. This causes a decrease in the population densit y and diversity of microorganisms both in space (in mineral horizons) and t ime (by the end of the growing season).