Lateral Transport Supports Southern Ocean Carbon Dioxide Outgassing
Schematic of the annually integrated fluxes of carbon in the Southern Ocean mixed layer.
Image by Jade Sauvé, University of Washington
In this study, we use year-round data collected by autonomous instruments to quantify the budget of carbon in the surface layer of the ocean, quantifying the different sources and sinks of inorganic carbon. We find that wind-driven circulation transports carbon from the south to the north, where it is transferred to the atmosphere as carbon dioxide.
Our results show that year-round measurements of carbon are necessary to understand carbon cycling in the region and we provide a useful product to compare to global simulations of the Earth system.
The ocean surrounding the frozen continent of Antarctica plays an important role in the global cycling of carbon and is important for the climate of our planet. Despite its
importance, there are gaps in our knowledge due to the difficulties involved in collecting data from a remote, seasonally ice-covered ocean. Our study shows that carbon mostly enters the surface layer through mixing with carbon-rich waters below. In the more stormy, northern part of our study area, this carbon is then either consumed by photosynthesis in the ocean or it is transferred to the atmosphere. In the southernmost region, biological activity and gas transfer at the ocean-atmosphere interface is hindered by the presence of sea ice and the surplus of carbon is instead transferred north by wind-driven circulation.