Specific Features of Nitrogen and Carbon Transformation in an Oligotrophic Peat Soil

In the course of field and laboratory studies, the activities of nitrogen fixation, denitrification, CO 2 emission, and methane formation in an oligotrophic peat soil were determined at the Staroselsky Mokh Station of the Central Forest State Natural Biospheric Reserve in Tver oblast. The high intensity of methane oxidation was found in the oligotrophic peat soil. It was supposed that methane under these conditions could be used by diazotrophic bacteria as energy source. Determination of the nitrogen-fixing activity of oligotrophic peat soil in the presence of methane showed a sharp increase in the nitrogenase activity. It is important to emphasize that nitrogenase activity was higher in the presence of methane, even in comparison with the variant with glucose. The preferential absorption of nitrous oxide by the upper horizon of oligotrophic peat soils was found, which allowed us to consider these ecosystems to be a natural sink for N 2 O.