Global Patterns and Environmental Drives of Nitrite/Nitrate‐Dependent Anaerobic Methane Oxidation Across Natural Ecosystems

Abstract

The nitrite/nitrate‐dependent anaerobic methane oxidation (DAMO) plays a crucial role in mitigating methane (CH 4 ) emissions and nitrogen (N) loadings in natural ecosystems, significantly contributing to global CH 4 consumption and N balances. However, the global patterns and environmental drivers of these processes across natural ecosystems remain unclear, hindering the estimation and management of global CH 4 emissions. In this study, we compiled a global dataset comprising 527 observations from 59 published studies across terrestrial and aquatic ecosystems. We found a global mean N‐DAMO rate of 19.2 nmol g −1 d −1 , which includes a mean nitrite‐DAMO rate of 13.8 nmol g −1 d −1 and a mean nitrate‐DAMO rate of 7.4 nmol g −1 d −1 . Notably, N‐DAMO rates were higher in soils from croplands (47.9 nmol g −1 d −1 ) and forests/grasslands (30.9 nmol g −1 d −1 ) compared to those from freshwater (8.4 nmol g −1 d −1 ) and coastal regions (12.7 nmol g −1 d −1 ). Nitrite‐DAMO contributes more than 50% of the N‐DAMO; however, this contribution was lowest in coastal regions (51.1%). The rates of N‐DAMO exhibited a unimodal relationship with temperature and a significantly negative relationship with precipitation. Among soil properties, extractable N, substrates for N‐DAMO, showed significant inhibition on N‐DAMO rates, implying a diminished role of N‐DAMO in global N enrichment scenarios. Our results illustrate that N‐DAMO across natural ecosystems can reduce CH 4 emissions by 229.6 Tg year −1 and has substantial potential for N removal worldwide. This work highlights the significance of N‐DAMO for global CH 4 emission estimation and N management.

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