Nitrite-dependent methane-oxidizing bacteria seasonally and spatially shift in a constructed wetland used for treating river water

Nitrite-dependent anaerobic methane oxidation (n-damo) process, performed by “Candidatus Methylomirabilis oxyfera” (M. oxyfera), can be an important methane sink in wetland anoxic layers. However, little is known about the distribution and variability of M. oxyfera-like bacteria in constructed wetlands (CWs). The current study investigated spatial and seasonal dynamics of M. oxyfera-like bacteria in a free water surface flow CW (FWSF-CW) used to improve river water quality and explored the influences of wetland environmental variables. In the FWSF-CW, M. oxyfera-like bacterial abundance was found to change considerably among both sampling sites and seasons, ranged between 8.99 × 105 and 4.34 × 106 16S rRNA gene copies per gram dry sediment/soil. Considerable spatial and seasonal variations of M. oxyfera-like bacterial richness, diversity, and community structure were also observed in the FWSF-CW. In addition, both nutrients and temperature were the key factors determining the community structure of wetland M. oxyfera-like bacteria.