Typhoon‐Induced Nitrous Oxide Consumption in Coastal Open Waters and Its Climate Implications

Abstract The mechanisms coupling typhoons with nitrous oxide (N 2 O), a potent greenhouse gas, have gained increasing significance under global climate change. This study investigates the N 2 O biogeochemical responses to Typhoon Yagi in the western Guangdong coastal waters (WGCW) by integrating analyses of nitrogen isotopes (δ 15 N bulk ‐N 2 O), oxygen isotopes (δ 18 O‐N 2 O), intramolecular 15 N site preference (SP), and ancillary biogeochemical parameters. Post‐typhoon data revealed a pronounced decline in SP values, followed by a gradual enrichment of SP, δ 15 N bulk ‐N 2 O, and δ 18 O‐N 2 O over the time series sampling. These phenomena indicated that typhoon disturbance shifted the dominant nitrogen cycling processes from nitrification to denitrification which involved significant N 2 O reduction and consumption, likely driven by particulate matter inputs and subsequent degradation. Additionally, although a two‐layer model indicated a substantial atmospheric N 2 O influx into the marine environment across the air‐sea interface, N 2 O concentrations remained stable in the WGCW after the typhoon. This stability was accompanied by the concurrent decoupling of δ 18 O versus δ 15 N α , δ 18 O versus δ 15 N bulk , and δ 18 O versus SP correlations, supporting the occurrence of high N 2 O reduction rates during denitrification which maintained stable N 2 O concentrations after the typhoon. Furthermore, a comparative analysis of different marine environments revealed distinct N 2 O dynamics following typhoons: enclosed bay tends to become significant atmospheric N 2 O sources, while the open ocean primarily acts as a sink. These findings suggest a negative feedback mechanism in which open ocean typhoon events enhance denitrification, potentially mitigating atmospheric N 2 O accumulation.