Regulation of coastal methane sinks by a structured gradient of microbial methane oxidizers
Regulation of coastal methane sinks by a structured gradient of microbial methane oxidizers
复制标题
通过微生物甲烷氧化剂的结构化梯度调节沿海甲烷汇
DOI：
10.1016/j.envpol.2018.10.057
复制
发表时间：
2019-01-01
影响因子：
8.9
通讯作者：
Hu, Baolan
中科院分区：
文献类型：
--
作者：
He, Zhanfei;Wang, Jiaqi;Hu, Baolan
Coastal wetlands are widely recognized as atmospheric methane sources. However, recent field studies suggest that some coastal wetlands could also act as methane sinks, but the mechanism is not yet clear. Here, we investigated methane oxidation with different electron acceptors (i.e., oxygen, nitrate/nitrite, sulfate, Fe(III) and Mn(IV)) in four coastal wetlands in China using a combination of molecular biology methods and isotopic tracing technologies. The geochemical profiles and in situ Gibbs free energies suggest that there was significant nitrite-dependent anaerobic oxidation of methane (nitrite-AOM) in the sub-surface sediments; this was subsequently experimentally verified by both the microbial abundance and activity. Remarkably, the methanotrophic communities seemed to exist in the sediments as layered structures, and the surface aerobic methane-oxidizing bacteria were able to take up atmospheric methane at a rate of 0.10-0.18 nmol CH4 day(-1) cm(-2), while most, if not all, sedimentary methane was being completely consumed by anaerobic methanotrophs (23-58% by methane oxidizers in phylum NC10). These results suggest that coastal methane sinks might be governed by diverse microbial communities where NC10 methane oxidizers contributed significantly. This finding helps to better understand and predict the coastal methane cycle and reduce uncertainties in the estimations of the global methane flux. (C) 2018 Elsevier Ltd. All rights reserved.
