Mangrove species and soil properties influence soil carbon dioxide and methane fluxes from heterotrophic and root‐affected sources in an estuarine mangrove

Abstract Mangroves offer substantial carbon sequestration, acting as nature‐based climate solutions. Yet, soil carbon dioxide (CO 2 ) and methane (CH 4 ) emissions partially offset these benefits. Despite many studies on emission patterns and drivers, lacking source‐specific partitioning hinders deeper mechanistic insights. Here, a 1‐yr in situ experiment using deep collar insertion in Kandelia obovata and Avicennia marina forests partitioned soil CO 2 and CH 4 fluxes into heterotrophic and root‐affected sources, examining seasonal dynamics, temperature sensitivity ( Q 10 ), and soil properties controls. Soil–air carbon fluxes, except for root‐affected CH 4 , were lowest in winter and peaked in summer or autumn. Soil and root‐affected CH 4 fluxes were significantly higher in A. marina forests than in K. obovata forests annually or seasonally. The annual flux ratio of root‐affected CO 2 to soil CO 2 averaged 39%, and was relatively 19% higher in A. marina forests than in K. obovata forests. Soil properties collectively explained 64%, 62%, and 36% of variation in soil, heterotrophic, and root‐affected CO 2 fluxes, respectively, but only 3%, 22%, and −9% for corresponding CH 4 fluxes. The Q 10 of soil CH 4 fluxes was significantly higher in A. marina forests than in K. obovata forests, and root‐affected CO 2 fluxes had a higher Q 10 than heterotrophic CO 2 fluxes only in A. marina forests. These findings reveal mangrove species‐specific differences in the magnitude and Q 10 of soil–air carbon fluxes, underscoring mangrove species as key to assessing climate benefits and guiding restoration. We also emphasize the role of soil conditions and flux partitioning in predicting soil CO 2 and CH 4 fluxes, respectively.