长江口沉积物甲烷产生潜力与产甲烷菌群落特征

In this study, incubation experiments and molecular approaches were used to investigate the methane emission potential and associated methanogens community in the sediments of the Yangtze Estuary. The results indicate that the methane emission rates were in the range of 4.15~7.12 nmol•g^-1•d^-1, which were higher in anaerobic sites than in aerobic sites. However, the methane production potential was higher in aerobic sites than anaerobic sites, which suggested that methane oxidation in water was the important process reducing the methane emission from sediment to atmosphere. The methanogens communities differed across the sampling sites. Methanococcoides, Methanosarcina and Methanosaeta were the dominated communities in the anaerobic sites, and Methanosarcina, Methanosaeta and Methanocella were the important communities in aerobic sites, indicating the importance of oxygen depletion process to alter methanogens community composition. The estimated mean annual amount of methane emission was approximately 2487~6819 t•a^-1, suggesting that Yangtze Estuary is the net source of methane emission. Overall, these results indicate that the variations in environmental factors induced by oxygen depletion process strongly influence the metabolic cycling of methane and associated microbial communities, which further play an important role in regulating the methane emission in estuarine ecosystems.