Closing Off the Southern-Ocean Surface

Equilibrium integrations with the three-dimensional Hamburg ocean carbon cycle circulation model show the effect of a Southern Ocean surface outcrop that is closed off for gas exchange with the atmosphere and export production of particulate organic carbon and CaCO3 south of 32.5 degrees S. For such a close-off, the northern Atlantic outcrop assumes a greater degree of control of atmospheric CO2 partial pressure. Contrary to expectations, the atmospheric pCO(2) increases compared to a control run without close-off. Maximizing the nutrient utilization in the North Atlantic can compensate for this increase. However, it does not draw down the pCO(2) to glacial levels.