The fate of methane in ponds: Drivers of production, storage, oxidation, and emissions

Abstract

Ponds are disproportionately large contributors to global carbon cycling, with substantial but variable emissions of methane (CH4) to the atmosphere relative to their global surface area. Efforts to upscale pond CH4 emissions have focused on broad‐scale correlates of emissions, yet mechanisms underlying the variability in emissions remain poorly constrained. In this study, we quantified total CH4 production in 15 ponds across New York State (USA) using a mass‐balance approach, and partitioned CH4 production into its major pathways: storage, oxidation, and emissions. We found that total CH4 production was strongly regulated by metrics of ecosystem productivity (R2 = 0.77), while CH4 storage accumulation rates and emissions were both controlled by pond morphology, stratification, and sheltering. Oxidation greatly influenced emissions, but remained difficult to predict. By quantifying all CH4 pathways, our study clarifies drivers of CH4 production, transport, and ultimately emissions, which can improve the accuracy of upscaling efforts.