Anaerobic methane oxidation coupled to nitrite reduction can be a potential methane sink in coastal environments

• DOI: 10.1007/s00253-016-7627-0
• Publication Date: 2016-05-25T16:27:21Z
• Authors: Li-dong Shen; Bao-lan Hu; Shuai Liu; Xiao-ping Chai; Zhan-fei He; Hong-xing Ren; Yan Liu; Sha Geng; Wei Wang; Jing-liang Tang; Yi-ming Wang; Li-ping Lou; Xiang-yang Xu; Ping Zheng
• Keywords: DNA, Bacterial; 0301 basic medicine; Geologic Sediments; Salinity; 0303 health sciences; Nitrates; Bacteria; Base Sequence; Sequence Analysis, DNA; 6. Clean water; 03 medical and health sciences; Bays; 13. Climate action; Isotope Labeling; RNA, Ribosomal, 16S; Anaerobiosis; 14. Life underwater; Methane; Oxidation-Reduction; Nitrites; Phylogeny; Soil Microbiology

In the current study, we investigated nitrite-dependent anaerobic methane oxidation (N-DAMO) as a potential methane sink in the Hangzhou Bay and the adjacent Zhoushan sea area. The potential activity of the N-DAMO process was primarily observed in Hangzhou Bay by means of (13)C-labeling experiments, whereas very low or no potential N-DAMO activity could be detected in the Zhoushan sea area. The measured potential N-DAMO rates ranged from 0.2 to 1.3 nmol (13)CO2 g(-1) (dry sediment) day(-1), and the N-DAMO potentially contributed 2.0-9.4 % to the total microbial methane oxidation in the examined sediments. This indicated that the N-DAMO process may be an alternative pathway in the coastal methane cycle. Phylogenetic analyses confirmed the presence of Candidatus Methylomirabilis oxyfera-like bacteria in all the examined sediments, while the group A members (the dominant bacteria responsible for N-DAMO) were found mainly in Hangzhou Bay. Quantitative PCR showed that the 16S rRNA gene abundance of Candidatus M. oxyfera-like bacteria varied from 5.4 × 10(6) to 5.0 × 10(7) copies g(-1) (dry sediment), with a higher abundance observed in Hangzhou Bay. In addition, the overlying water NO3 (-) concentration and salinity were identified as the most important factors influencing the abundance and potential activity of Candidatus M. oxyfera-like bacteria in the examined sediments. This study showed the evidence of N-DAMO in coastal environments and indicated the importance of N-DAMO as a potential methane sink in coastal environments.