title: Vertical distribution of nitrite-dependent anaerobic methane-oxidising bacteria in natural freshwater wetland soils.
abstract: Nitrite-dependent anaerobic methane oxidation (n-damo) is a recently discovered process that is catalysed by "Candidatus Methylomirabilis oxyfera". In the present study, the vertical distribution (0-10, 20-30, 50-60 and 90-100 cm) of M. oxyfera-like bacteria was investigated in Xiazhuhu wetland, the largest natural wetland on the southern Yangtze River (China). Phylogenetic analyses showed that group A of M. oxyfera-like bacteria and pmoA genes occurred primarily at depths of 50-60 and 90-100 cm. Quantitative PCR further confirmed the presence of M. oxyfera-like bacteria in soil cores from different depths, with the highest abundance of 5.1 × 10(7) copies g(-1) dry soil at depth of 50-60 cm. Stable isotope experiments demonstrated that the n-damo process occurred primarily at depths of 50-60 and 90-100 cm, with the potential rates ranging from 0.2 to 14.5 nmol CO2 g(-1) dry soil d(-1). It was estimated that the methane flux may increase by approximately 2.7-4.3% in the examined wetland in the absence of n-damo. This study shows that the deep wetland soils (50-60 and 90-100 cm) are the preferred habitats for M. oxyfera-like bacteria. The study also highlights the potential importance of these bacteria in the methane and nitrogen cycles in deep wetland soils.
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Li-dong
authors.initials: LD
authors.lastname: Shen
authors.forename: Qian
authors.initials: Q
authors.lastname: Huang
authors.forename: Zhan-fei
authors.initials: ZF
authors.lastname: He
authors.forename: Xu
authors.initials: X
authors.lastname: Lian
authors.forename: Shuai
authors.initials: S
authors.lastname: Liu
authors.forename: Yun-feng
authors.initials: YF
authors.lastname: He
authors.forename: Li-ping
authors.initials: LP
authors.lastname: Lou
authors.forename: Xiang-yang
authors.initials: XY
authors.lastname: Xu
authors.forename: Ping
authors.initials: P
authors.lastname: Zheng
authors.forename: Bao-lan
authors.initials: BL
authors.lastname: Hu
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000145:classification* / Q000302:isolation & purification / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics; D058448:Biota; D002681:China; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005618:Fresh Water; D007553:Isotope Labeling; D008697:Methane / Q000378:metabolism*; D008969:Molecular Sequence Data; D009573:Nitrites / Q000378:metabolism*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D053833:Wetlands
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D009573:Nitrites; D008697:Methane