Coastal Southern Ocean: A strong anthropogenic CO2 sink

Large-scale estimates of the Southern Ocean CO2 sink do not adequately resolve the fluxes associated with Antarctic continental shelves. Using a mechanistic three-dimensional biogeochemical model of the Ross Sea, we show that Antarctic shelf waters are a strong sink for CO2 due to high biological productivity, intense winds, high ventilation rates, and extensive winter sea ice cover. Net primary production (NPP) in these waters is similar to 0.055 Pg C yr(-1). Some of this carbon sinks to depth, driving an influx of CO2 of 20-50 g C m(-2) yr(-1). Although currently unaccounted for, the total atmospheric CO2 sink on the Ross Sea continental shelf of 0.013 Pg C yr(-1) is equivalent to 27% of the most recent estimate of the CO2 sink for the entire Southern Ocean. Given these results, these and other highly productive waters around the Antarctic continent need to be included in future budgets of anthropogenic CO2. Citation: Arrigo, K. R., G. van Dijken, and M. Long (2008), Coastal Southern Ocean: A strong anthropogenic CO2 sink, Geophys. Res. Lett., 35, L21602, doi: 10.1029/2008GL035624.