Chen Feiyang, Niu Yuhui, An Zhirui, Wu Li, Zhou Jie, Qi Lin, Yin Guoyu, Dong Hongpo, Li Xiaofei, Gao Dengzhou, Liu Min, Zheng Yanling, Hou Lijun
State Key Laboratory of Estuarine and Coastal Research, Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education & Shanghai, East China Normal University, Shanghai 200241, China.
School of Geographic Sciences, East China Normal University, Shanghai 200241, China; Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, Shanghai 200241, China.
Water Res. 2023 Feb 1;229:119436. doi: 10.1016/j.watres.2022.119436. Epub 2022 Nov 27.
Nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) plays an important role in methane (CH) 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 CH, which may help accurately project CH emission from intertidal wetlands under different tidal scenarios.
亚硝酸盐/硝酸盐依赖型厌氧甲烷氧化（n-DAMO）在潮间带湿地的甲烷（CH₄）消耗中发挥着重要作用。然而，关于潮间带湿地中n-DAMO对潮汐循环引起的周期性干湿变化的响应却知之甚少。在此，对长江河口潮间带沉积物进行了对比实验（淹水、干燥、再淹水），以研究周期性潮汐变化对n-DAMO微生物群落、丰度和潜在活性的影响。功能基因测序表明，n-DAMO细菌和古菌在潮汐波动环境中共存，且再淹水条件下的生物多样性总体上高于连续淹水或暴露条件。在交替暴露和淹水过程中，n-DAMO微生物丰度和相关活性有显著变化，淹水条件下的丰度和活性高于干燥条件。潮间带湿地的再淹水可能会增强n-DAMO活性，表示n-DAMO微生物代谢对干湿事件具有恢复力。结构方程模型和相关性分析表明，淹水条件下n-DAMO活性与n-DAMO微生物丰度和底物可用性高度相关，而干燥条件下沉积物中的盐分积累是抑制n-DAMO活性的主要因素。总体而言，本研究揭示了潮汐引起的n-DAMO活性变化及其对减轻CH₄排放的相关贡献，这可能有助于准确预测不同潮汐情景下潮间带湿地的CH₄排放。
