Effects of periodic drying-wetting on microbial dynamics and activity of nitrite/nitrate-dependent anaerobic methane oxidizers in intertidal wetland sediments

• DOI: 10.1016/j.watres.2022.119436
• Publication Date: 2022-11-28T04:14:53Z
• Authors: Feiyang Chen; Yuhui Niu; Zhirui An; Li Wu; Jie Zhou; Lin Qi; Guoyu Yin; Hongpo Dong; Xiaofei Li; Dengzhou Gao; Min Liu; Yanling Zheng; Lijun Hou
• Keywords: 0301 basic medicine; 03 medical and health sciences; Nitrates; 13. Climate action; Wetlands; RNA, Ribosomal, 16S; Denitrification; Anaerobiosis; Methane; Oxidation-Reduction; Nitrites; 6. Clean water

Nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) plays an important role in methane (CH4) consumption in intertidal wetlands. However, little is known about the responses of n-DAMO in intertidal wetlands to periodic drying-wetting caused by tidal cycling. Here, comparative experiments (waterlogged, desiccated, reflooded) with the Yangtze estuarine intertidal sediments were performed to examine the effects of periodic tidal changes on n-DAMO microbial communities, abundances, and potential activities. Functional gene sequencing indicated the coexistence of n-DAMO bacteria and archaea in the tide-fluctuating environments and generally higher biodiversity under reflooded conditions than consecutive inundation or emersion. The n-DAMO microbial abundance and associated activity varied significantly during alternative exposure and inundation, with higher abundance and activity under the waterlogged than desiccated conditions. Reflooding of intertidal wetlands might intensify n-DAMO activities, indicating the resilience of n-DAMO microbial metabolisms to the wetting-drying events. Structural equation modeling and correlation analysis showed that n-DAMO activity was highly related to n-DAMO microbial abundance and substrate availability under inundation, whereas salt accumulation in sediment was the primary factor restraining n-DAMO activity under the desiccation. Overall, this study reveals tidal-induced shifts of n-DAMO activity and associated contribution to mitigating CH4, which may help accurately project CH4 emission from intertidal wetlands under different tidal scenarios.