Methane Emissions and Dynamics in the Weddell and Scotia Seas

Abstract The Southern Ocean's role in the global methane () cycle remains uncertain due to limited measurement data from this remote region. It is unclear if the Southern Ocean acts as a source or sink of atmospheric , and climatic changes can have consequences on the amount of marine released due to the acceleration of glacial melting and uncertain consequences on seabed reservoirs. Monitoring here is essential to understanding its impact on the global budget now and in the future. This study measured concentrations in both ocean and atmosphere during an expedition in the Scotia Sea, Weddell Sea, and South Georgia shelf, linking seabed activity, water column concentrations, sea‐air fluxes, and atmospheric levels. All areas were found to be a small source of to the atmosphere. Surface water concentrations of off‐shelf waters were found to be lower south of the Southern Antarctic Circumpolar Current front, where upwelling brings ‐depleted waters to the surface. On‐shelf regions show higher emissions compared to off‐shelf, with average sea‐air fluxes of 0.269 0.035 μmol m −2 d −1 and 0.136 0.021 μmol m −2 d −1 , respectively, likely due to seabed seepage and methane‐enriched freshwater. This study finds that the Weddell and Scotia seas (including the South Georgia shelf) are a small source of atmospheric . As this result contradicts previous studies identifying this area as a sink, continued monitoring is needed to understand how emissions are changing and may continue to change in the future.