Methyl-compounds driven benthic carbon cycling in the sulfate-reducing sediments of South China Sea.

Autor: Xu L; State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China., Zhuang GC; Frontiers Science Centre for Deep Ocean Multispheres and Earth System (FDOMES)/Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China.; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.; Department of Marine Sciences, University of Georgia, Athens, GA, 30602, USA., Montgomery A; Department of Marine Sciences, University of Georgia, Athens, GA, 30602, USA., Liang Q; Guangzhou Marine Geological Survey, China Geological Survey, Guangzhou, 510740, China., Joye SB; Department of Marine Sciences, University of Georgia, Athens, GA, 30602, USA., Wang F; State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.; School of Oceanography, Shanghai Jiao Tong University, Shanghai, 200240, China.
Jazyk: angličtina
Zdroj: Environmental microbiology [Environ Microbiol] 2021 Feb; Vol. 23 (2), pp. 641-651. Date of Electronic Publication: 2020 Jul 01.
DOI: 10.1111/1462-2920.15110
Abstrakt: Methane is a potent greenhouse gas; methane production and consumption within seafloor sediments has generated intense interest. Anaerobic oxidation of methane (AOM) and methanogenesis (MOG) primarily occur at the depth of the sulfate-methane transition zone or underlying sediment respectively. Methanogenesis can also occur in the sulfate-reducing sediments through the utilization of non-competitive methylated compounds; however, the occurrence and importance of this process are not fully understood. Here, we combined a variety of data, including geochemical measurements, rate measurements and molecular analyses to demonstrate the presence of a cryptic methane cycle in sulfate-reducing sediments from the continental shelf of the northern South China Sea. The abundance of methanogenic substrates as well as the high MOG rates from methylated compounds indicated that methylotrophic methanogenesis was the dominant methanogenic pathway; this conclusion was further supported by the presence of the methylotrophic genus Methanococcoides. High potential rates of AOM were observed in the sediments, indicating that methane produced in situ could be oxidized simultaneously by AOM, presumably by ANME-2a/b as indicated by 16S rRNA gene analysis. A significant correlation between the relative abundance of methanogens and methanotrophs was observed over sediment depth, indicating that methylotrophic methanogenesis could potentially fuel AOM in this environment. In addition, higher potential rates of AOM than sulfate reduction rates at in situ methane conditions were observed, making alternative electron acceptors important to support AOM in sulfate-reducing sediment. AOM rates were stimulated by the addition of Fe/Mn oxides, suggesting AOM could be partially coupled to metal oxide reduction. These results suggest that methyl-compounds driven methane production drives a cryptic methane cycling and fuels AOM coupled to the reduction of sulfate and other electron acceptors.
(© 2020 Society for Applied Microbiology and John Wiley & Sons Ltd.)
Databáze: MEDLINE
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