LAUSR

The recently discovered nitrite-dependent anaerobic methane oxidation (n-damo) is an important methane sink in natural ecosystems performed by NC10 phylum bacteria. However, the effect of water table gradient due to global change on n-damo bacterial communities is not well studied in peatlands. Here, we analyzed the vertical distribution (0-100 cm) of n-damo bacterial communities at three sites with different water tables (WT), Zoige peatlands in the Qinghai-Tibetan Plateau. Using n-damo bacterial specific 16S rRNA gene clone library, we obtained 25 operational taxonomic units (OTUs), which could be divided into Group A, B, C, D and E (dominated by A and B). The dominant group was Group B at the high WT site (OTU14 and OTU20) and intermediate WT site (OTU7 and OTU8) and was Group A at the low WT site (OTU6 and OTU5). Using high-throughput sequencing, we observed that n-damo bacteria mainly distributed in subsurface soils (50-60 and 20-30 cm), and their relative abundances were higher at the low WT site than the other two sites. In addition, we found that pH and nitrate were positively correlated to Group A, while total organic carbon, total nitrogen and ammonia were positively associated with Group B. Our study provides new insights into our understanding the response of n-damo bacteria to WT gradient in peatlands with important implications for global change.