作者：Zhang, MP; Luo, Y; Lin, LA; Lin, XL; Hetharua, B; Zhao, WJ; Zhou, MK; Zhan, Q; Xu, H; Zheng, TL; Tian, Y

影响因子：3.34

刊物名称：APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

出版年份：2018

卷：102(5) 页码：2441-2454

Nitrite-dependent anaerobic methane oxidation (n-damo), which is mediated by “Candidatus Methylomirabilis oxyfera-like” bacteria, is unique in linking the carbon and nitrogen cycles. However, the niche and activity of n-damo bacteria in the mangrove ecosystem have not been confirmed. Here, we report the occurrence of the n-damo process in the mangrove wetland of the Zhangjiang Estuary, China. The widespread occurrence of n-damo bacteria in mangrove wetland was confirmed using real-time quantitative polymerase chain reaction (qPCR) assay, which showed that the abundance of Methylomirabilis oxyfera-like bacterial 16S rRNA and pmoA genes ranged from 2.43 × 106 to 2.09 × 107 and 2.07 × 106 to 3.38 × 107copies per gram of dry soil in the examined sediment cores. The highest amount of targeting genes was all detected in the upper layer (0–20 cm). Phylogenetic analyses of n-damo bacterial 16S rRNA and pmoA genes illustrated the depth-specific distribution and high diversity of n-damo bacteria in the mangrove wetland. Stable isotope experiments further confirmed the occurrence of n-damo in the examined mangrove sediments, and the potential n-damo rates ranged from 25.93 to 704.08 nmol CO2 per gram of dry soil per day at different depths of the sediment cores, with the n-damo being more active in the upper layer of the mangrove sediments. These results illustrate the existence of active M. oxyfera-like bacteria and indicate that the n-damo process is a previously overlooked microbial methane sink in the mangrove wetlands.

Figure 4. Spatiotemporal distribution patterns of n-damo bacterial abundance in sediment cores collected from Aegiceras corniculatum (AC), Rhizophora candel (RC), and Avicennia marina (AM) habitats in the mangrove wetland. Error bars indicate standard deviation (n = 3).