Microbial dynamics and activity of denitrifying anaerobic methane oxidizers in China's estuarine and coastal wetlands

Abstract Estuarine and coastal wetlands, which act as large sources of methane (CH4) and undergo substantial loading of anthropogenic nitrogen (N), provide ideal conditions for denitrifying anaerobic methane oxidation (DAMO) to occur. Yet the microbial mechanisms governing DAMO and the main driving factors in estuarine and coastal ecosystems remain unclear. This study investigated the spatiotemporal distribution and associated activity of DAMO microorganisms along a wide swath of China's coastline (latitudinal range: 22–41°N) using molecular assays and isotope tracing techniques. We uncovered significant spatial and seasonal variation in DAMO bacterial community structure, whereas DAMO archaeal community structure exhibited no seasonal differences. The abundance of DAMO bacterial pmoA gene (2.2 × 105–1.0 × 107 copies g−1) was almost one order of magnitude higher than that of DAMO archaeal mcrA gene (8.7 × 104 –1.8 × 106 copies g−1). A significant positive correlation between pmoA and mcrA gene abundances (p