Role of n-DAMO in Mitigating Methane Emissions from Intertidal Wetlands Is Regulated by Saltmarsh Vegetations
Zhirui An, Feiyang Chen, Yanling Zheng, Jie Zhou, Bolin Liu, Lin Qi, Zhuke Lin, Cheng Yao, Bin Wang, Yixuan Wang, Xiaofei Li, Guoyu Yin, Hongpo Dong, Xia Liang, Min Liu, Lijun Hou
Abstract
Coastal wetlands are hotspots for methane (CH 4 ) production, reducing their potential for global warming mitigation. Nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) plays a crucial role in bridging carbon and nitrogen cycles, contributing significantly to CH 4 consumption. However, the role of n-DAMO in reducing CH 4 emissions in coastal wetlands is poorly understood. Here, the ecological functions of the n-DAMO process in different saltmarsh vegetation habitats as well as bare mudflats were quantified, and the underlying microbial mechanisms were explored. Results showed that n-DAMO rates were significantly higher in vegetated habitats ( Scirpus mariqueter and Spartina alterniflora ) than those in bare mudflats ( P < 0.05), leading to an enhanced contribution to CH 4 consumption. Compared with other habitats, the contribution of n-DAMO to the total anaerobic CH 4 oxidation was significantly lower in the Phragmites australis wetland (15.0%), where the anaerobic CH 4 oxidation was primarily driven by ferric iron (Fe 3+ ). Genetic and statistical analyses suggested that the different roles of n-DAMO in various saltmarsh wetlands may be related to divergent n-DAMO microbial communities as well as environmental parameters such as sediment pH and total organic carbon. This study provides an important scientific basis for a more accurate estimation of the role of coastal wetlands in mitigating climate change.