Function of the methanogenic community in mangrove soils as influenced by the chemical properties of the hydrosphere

ABSTRACTCoastal ecosystems represent a potential additional source of the greenhouse gas methane (CH4) that has been insufficiently quantified. Thus, to understand the mechanisms controlling greenhouse gas emissions in these ecosystems, this study investigated CH4 emissions from and the related microbial properties of mangrove soils. Soil and gas samples were collected from several plots at different distances from the seashore in Soc Trang and Ca Mau in Vietnam, and the Sundarbans in India. Soil samples were incubated under different conditions, i.e., anaerobic or aerobic, and the microbial properties of each soil sample with the addition of different amounts of seawater were analyzed. Relatively high CH4 fluxes and production were detected during the aerobic incubation of samples from the seashore plots in Soc Trang and Ca Mau. However, CH4 production was reduced under anaerobic conditions [soil electrical conductivity (EC): 179–289 mS m−1, pH (H2O): 7.45–8.10] compared with aerobic conditions [water co...