Ecological Variability and Controls on Denitrifying Anaerobic Methane Oxidation

Abstract Denitrifying anaerobic methane oxidation (DAMO) constitutes a key biogeochemical nexus, concurrently mitigating atmospheric methane emissions and coupling global carbon and nitrogen cycles. However, a quantitative and mechanistic understanding of its ecological variability and global‐scale drivers is lacking, hindering its realistic representation in Earth system models. This study provides a comprehensive global synthesis of DAMO rates and their environmental controls across diverse ecosystems. Nitrate‐ and nitrite‐dependent anaerobic methane oxidation (Nitrate‐ and Nitrite‐AOM) exhibited mean rates of 8.4 ± 0.8 (mean ± SE) and 5.4 ± 0.7 nmol CO 2 (g dry weight) −1 day −1 , respectively. Paddy ecosystems were identified as global hotspots, with rates significantly exceeding those in estuaries, forests and grasslands. Functional gene ( mcrA , pmoA ) abundance, mean monthly temperature and depth jointly explained more than 60% of the rate variance across ecosystems in our analysis, indicating that they represent major drivers within the compiled data set. Notably, depth exerted an indirect control by regulating gene abundance, leading to a depth zonation where Nitrite‐AOM dominated in shallower zones over Nitrate‐AOM. Globally, DAMO mitigated more than 24% of the CH 4 consumed by anaerobic oxidation, with paddies alone offsetting over 25% of their total CH 4 production. By resolving the multi‐level controls from genes to climate, this work bridges microbial ecology and Earth system science, providing a predictive framework to incorporate this key methane sink into global models and inform targeted mitigation strategies.