Vertical distribution of nitrite-dependent anaerobic methane-oxidising bacteria in natural freshwater wetland soils

• DOI: 10.1007/s00253-014-6031-x
• Publication Date: 2014-09-22T01:21:31Z
• Authors: Li-dong Shen; Qian Huang; Zhan-fei He; Xu Lian; Shuai Liu; Yun-feng He; Li-ping Lou; Xiang-yang Xu; Ping Zheng; Bao-lan Hu
• Keywords: DNA, Bacterial; 0301 basic medicine; China; 0303 health sciences; Bacteria; Molecular Sequence Data; Fresh Water; Sequence Analysis, DNA; 15. Life on land; Biota; Polymerase Chain Reaction; 6. Clean water; 03 medical and health sciences; Bacterial Proteins; Isotope Labeling; Wetlands; Cluster Analysis; Anaerobiosis; Methane; Nitrites; Phylogeny; Soil Microbiology

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.