title: Anaerobic methane oxidation coupled to nitrite reduction can be a potential methane sink in coastal environments.
abstract: 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.
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Li-Dong
authors.initials: LD
authors.lastname: Shen
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China. blhu@zju.edu.cn.
authors.forename: Bao-Lan
authors.initials: BL
authors.lastname: Hu
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Liu
authors.affiliation: Zhejiang Provincial Zhoushan Marine Ecological Environmental Monitoring Station, Zhoushan, 316021, China.
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Chai
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Zhan-Fei
authors.initials: ZF
authors.lastname: He
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Hong-Xing
authors.initials: HX
authors.lastname: Ren
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Sha
authors.initials: S
authors.lastname: Geng
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Zhejiang Provincial Zhoushan Marine Ecological Environmental Monitoring Station, Zhoushan, 316021, China.
authors.forename: Jing-Liang
authors.initials: JL
authors.lastname: Tang
authors.affiliation: Zhejiang Provincial Zhoushan Marine Ecological Environmental Monitoring Station, Zhoushan, 316021, China.
authors.forename: Yi-Ming
authors.initials: YM
authors.lastname: Wang
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Lou
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Xiang-Yang
authors.initials: XY
authors.lastname: Xu
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Zheng
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism*; D001483:Base Sequence; D061006:Bays / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D019015:Geologic Sediments / Q000382:microbiology*; D007553:Isotope Labeling; D008697:Methane / Q000378:metabolism*; D009566:Nitrates / Q000737:chemistry*; D009573:Nitrites / Q000737:chemistry*; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D054712:Salinity; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D009566:Nitrates; D009573:Nitrites; D012336:RNA, Ribosomal, 16S; D008697:Methane
keywords: Anthropogenic nitrogen pollution; Coastal environments; Hangzhou Bay; N-DAMO; Potential methane sink