Air-sea COsub2/sub fluxes and the controls on ocean surface ip/iCOsub2/sub seasonal variability in the coastal and open-ocean southwestern Atlantic Ocean: a modeling study

摘要

We use an eddy-resolving, regional ocean biogeochemical model to investigatethe main variables and processes responsible for the climatologicalspatio-temporal variability of pCO₂ and the air-sea CO₂ fluxes in thesouthwestern Atlantic Ocean. Overall, the region acts as a sink ofatmospheric CO₂ south of 30° S, and is close to equilibrium withthe atmospheric CO₂ to the north. On the shelves, the ocean acts as a weaksource of CO₂, except for the mid/outer shelves of Patagonia, which act assinks. In contrast, the inner shelves and the low latitude open ocean of thesouthwestern Atlantic represent source regions. Observednearshore-to-offshore and meridional pCO₂ gradients are well representedby our simulation. A sensitivity analysis shows the importance of thecounteracting effects of temperature and dissolved inorganic carbon (DIC)in controlling the seasonal variability of pCO₂. Biological productionand solubility are the main processes regulating pCO₂, with biologicalproduction being particularly important on the shelves. The role ofmixing/stratification in modulating DIC, and therefore surface pCO₂,is shown in a vertical profile at the location of the Ocean ObservatoriesInitiative (OOI) site in the Argentine Basin (42° S, 42° W).