MICROBIAL PROCESSES IN THE THICKNESS OF A RAISED BOG IN THE MIDDLE TAIGA

Rates of anaerobic microbial processes-methanogenesis, acetogenesis, a nd sulfate reduction-were studied across the vertical profile of a rai sed bog in the middle taiga. Methanogenesis, proceeding at a rate of 0 .35-75.70 mu g C/(kg wet peat day) as determined by the radioisotopic method, was found to be the predominant process; the rate of acetogene sis was 0.18-4.33 mu g C/(kg wet peat day), and that of sulfate reduct ion, 0.006-0.041 mu g S/(kg wet peat day). The rate of methanogenesis increased with depth, reaching its maximum value of 75.70 mu g C/(kg w et peat day) in the horizon adjacent to the bog bottom. The study of c arbon isotopic composition as a function of depth showed variation of delta(13)C of methane from -56.9 to -26.5 parts per thousand and that of carbonates dissolved in water from -23.4 to +4.7 parts per thousand . The occurrence of heavier methane and carbonates in the surface hori zon may be associated with methanogenesis from carbon dioxide generate d by root respiration.