Abstract：
Denitrifying anaerobic methane oxidation (DAMO) microorganisms, using nitrate/nitrite to oxidize methane, have been proved to be an important microbial methane sink in natural habitats. Increasing nitrogen deposit around the globe brings increased availability of substrates for these microorganisms. However, how elevated nitrogen level affects denitrifying methanotrophs has not been elucidated. In this study, sediment/soil samples from coastal wetland with continuous nitrogen input and paddy field with periodic nitrogen input were collected to investigate the influence of nitrogen input on the abundance and activity of denitrifying methanotrophs. The results indicated that nitrogen input significantly promoted DAMO microorganisms\' abundance and contribution to methane emission reduction. In the coastal wetland, the contribution rate of DAMO process to methane removal increased from 12.1% to 33.5% along with continuously elevated nitrogen level in the 3-year tracking study. In the paddy field, the DAMO process accounted for 71.9% of total methane removal when nitrogen fertilizer was applied during the growing season, exceeding the aerobic methane oxidation process. This work would help us better understand the microbial methane cycle and reduce uncertainties in the estimations of the global methane emission.
摘要：
反硝化厌氧甲烷氧化（DAMO）微生物，使用硝酸盐/亚硝酸盐氧化甲烷，已被证明是自然栖息地中重要的微生物甲烷汇。全球氮沉积物的增加带来了这些微生物的底物可用性的增加。然而,氮水平升高如何影响反硝化甲烷污染菌尚未阐明。在这项研究中,收集了连续氮输入的沿海湿地和周期性氮输入的稻田的沉积物/土壤样品，以研究氮输入对反硝化甲烷氧化菌丰度和活性的影响。结果表明，氮输入显着促进了DAMO微生物的丰度和对甲烷减排的贡献。在沿海湿地，在为期3年的跟踪研究中，DAMO工艺对甲烷去除的贡献率从12.1%增加到33.5%，同时氮水平持续升高。在稻田里,在生长季节施用氮肥时，DAMO工艺占甲烷总去除率的71.9%，超过好氧甲烷氧化过程。这项工作将有助于我们更好地了解微生物甲烷循环，并减少全球甲烷排放量估算中的不确定性。
