A global analysis on the distribution pattern of the bacteria coupling simultaneous methane oxidation to nitrite reduction

The dominant bacterium Candidatus Methylomirabilis oxyfera (NC10 phylum) was first identified from an enrichment culture and subsequently from various other habitats. To date, the global distribution pattern of this bacterium has not been summarized. This study analyzed the distribution pattern and diversity of nitrite-dependent anaerobic methane oxidation (n-damo) bacteria by retrieving 2343 and 2555 16S rRNA gene and pmoA sequences from public databases, respectively. The phylogenetic trees showed that the distribution of this bacterium in marine notably distinct from other habitats, and the 16S rRNA gene sequences amplified from enrichment cultures established a separate phylogenetic group. The highest richness of their community was detected in marine habitat. Shannon-Wiener index showed that the diversity of them was higher in marine and coastal habitats without distinctive differences between them. In addition, a significant community difference was also found between the marine and freshwater habitats by calculating ANOSIM p values and shared OTUs. PCoA analysis shows that their community composition is habitat specific and shaped by salinity or anthropogenic influence. This analysis provides a synthesis on the global diversity and distribution pattern of this new bacterium with currently available information to date.