The role of sea spray in atmosphere–ocean gas exchange

Sea spray facilitates the movement of matter and energy between the ocean and the atmosphere. While many of its contributions to heat and momentum transfer are relatively well understood, the contribution to chemical exchange, particularly gas exchange, remains less well known. This study provides an estimation of sea-spray gas-exchange potential for five gases (helium, neon, argon, oxygen and nitrogen) using a chemically modified microphysical model, the Andreas Gas Exchange Spray model. This model uses the physical evolution of the sea-spray droplet and gas-exchange equilibria to estimate the potential exchange of gases attributable to spray droplets. We find that sea spray does not contribute appreciably to gas exchange of helium and neon. However, for argon, oxygen and nitrogen, at high wind speeds (above 18 m s–1), sea-spray-droplet-facilitated exchange could contribute substantially to gas flux and is on the same order of magnitude as the empirically constrained direct exchange across the interface. Sea spray, as a potential pathway for atmosphere–ocean gas exchange, may improve gas-exchange predictions in the high-wind scenarios that are particularly important in the Southern Ocean polar region.