| Abstract: | Complex investigations of recent and Drevnechernomorian (ancient Black Sea) sediments from the outer shelf, continental slope,
and deep-water basin of the Russian Black Sea sector have been carried out using samples collected during cruise of the R/V
Professor Shtokman organized by the Institute of Oceanology of the Russian Academy of Sciences (March 2009) and expedition of “YUZHMORGEO” (summer
2006). Rates of the main anaerobic processes during diagenesis (sulfate reduction, dark CO2 fixation, methanogenesis, and methane oxidation) were studied for the first time in sediment cores of the studied area. Two
peaks in the rate of microbial processes and two sources of these processes were identified: the upper peak near the water-sediment
contact is related to the solar energy (OM substrate of the water column) and the lower peak at the base of the Drevnechernomorian
sediments with high(>1000 μM) methane concentration related to the energy of anaerobic methane oxidation. The neogenic labile
OM formed during this process is utilized by other groups of microorganisms. According to experimental data, the daily rate
of anaerobic methane oxidation is many times higher than that of methanogenesis, which unambiguously indicates the migration
nature of the main part of methane. |
