This dataset contains atmospheric methane and carbon dioxide concentration data in the Southern Ocean and South Atlantic Ocean, and dissolved methane concentration data from surface and water column seawater samples in the Scotia Sea, Weddell Sea, and South Georgia shelf taken onboard RRS Discovery during DY158 from December 2022 and January 2023. Atmospheric methane and carbon dioxide concentration was measured using a Los Gatos Ultraportable Greenhouse Gas Analyser (UGGA) G2311-f. The concentrations are 2 hour averaged and have been filtered based on wind direction to data corresponding to wind coming from behind the ship to remove sources of pollution from the ship stack. Surface seawater samples were taken either using the uncontaminated seawater system or from the surface sample from a CTD (Conductivity-Depth-Temperature) cast. Water column seawater samples were taken from a CTD with Niskin bottle rosette-casts at various depths spanning from the sea surface to the seafloor. The dissolved methane concentration in each seawater sample is measured using gas chromatography.

Funding source: This work was supported by the Natural Environment Research Council and the ARIES Doctoral Training Partnership (grant no. NE/S007334/1). The fieldwork was supported by the Collaborative Antarctic Science Scheme (CASS).