Change in the Southern Ocean: Responding to Antarctica

Precisely fifty years ago, in a 3-page letter to Deep-Sea Research, Henry Stommel (1958) highlighted the role played by Antarctica in driving the oceans’ abyssal circulation. Since then, many studies of the present and past ocean have redefined the close links between Antarctica and the Southern Ocean, and their influence on the global ocean and climate. To highlight those links, we briefly review Antarctica’s impact on the surface of the Southern Ocean at glacial-interglacial (G-I) and millennial timescales. The Southern Ocean is a sea of superlatives. It is dominated by the longest (24,000 km), largest (transport of ~137 106 m3 s-1) and only current to link the major oceans—the Antarctic Circumpolar Current (ACC) (Fig. 1). This complex system of flows is driven mainly by the westerly zonal winds. Much of its flow today is concentrated along several ocean fronts that also define the distribution of surface waters and include, from north to south, the Subantarctic, Polar, Southern, and Boundary Fronts (e.g., Orsi et al., 1995).