Key questions to be addressed within this theme are:

• Which surface ocean processes control GHG cycling at regional to global scales?
• What are the main feedback mechanisms between climate change and oceanic GHG emissions?
• How can we assess future oceanic fluxes of GHGs in a changing ocean and atmosphere?

Detailed regional analyses
To better quantify and predict the evolution of oceanic GHG budgets and air-sea fluxes, detailed analyses of key regions for GHG fluxes are required. These include the Southern Ocean, coastal zones, and oceanic Oxygen Minimum Zones. Recommended approaches include higher resolution numerical models which represent the coupling of key processes for circulation, ecosystems and relevant biogeochemistry, and detailed biogeographical sampling of marine ecosystems across gradients to characterise the variations in environmental drivers and GHG flux responses.

Increased density of observations
In order to reliably assess variations in GHG fluxes within the ocean and across the air-sea interface, a denser observing system is required; e.g. from ships, autonomous platforms (e.g., Argo floats, gliders), and moorings. Satellite observations of relevant marine ecosystem and oceanic properties should also be exploited and linked systematically to in-situ oceanic measurements.

Development of new analysis tools and extension of existing methodologies
Improved quantification of ocean-atmosphere carbon dioxide fluxes has been achieved by combining existing particulate carbon dioxide surface data with a range of mapping methods including spatial interpolation, multi-variate regressions and neural network analyses. These tools can be extended to the other GHGs to improve flux quantification and to further investigate the key underlying processes.