| The Southern Ocean is thought to have played a key role in past atmospheric carbon dioxide (CO2,(atm)) changes. Three main factors are understood to control the Southern Ocean's influence on CO2,(atm), via their impact on surface ocean pCO(2) and therefore regional ocean-atmosphere CO2 fluxes: 1) the efficiency of air-sea gas exchange, which may be attenuated by seasonal- or annual sea-ice coverage or the development of a shallow pycnocline; 2) the supply of CO2-rich water masses from the subsurface and the deep ocean, which is associated with turbulent mixing and surface buoyancy- and/or wind forcing; and 3) biological carbon fixation, which depends on nutrient availability and is therefore influenced by dust deposition and/or upwelling. In order to... |
