Annual balance and seasonal variability of sea-air CO2 fluxes in the Patagonia Sea: Their relationship with fronts and chlorophyll distribution

BIANCHI, ALEJANDRO A.; RUIZ-PINO, DIANA; ISBERT PERLENDER, HERNÁN G.; OSIROFF, ANA PAULA; SEGURA, VALERIA; LUTZ, VIVIAN; LUZ CLARA, MOIRA; BALESTRINI, CARLOS; PIOLA, ALBERTO

JOURNAL OF GEOPHYSICAL RESEARCH

AMER GEOPHYSICAL UNION

Año: 2009 vol. 114 p. 1 - 11

0148-0227

Sea-air differences of CO2 partial pressures (DeltapCO2) and fluxes over the Patagonia continental shelf and shelf break are estimated based on near surface observations collected between 2000 and 2006. Chlorophyll-a (Chl-a) surface distributions and the thermohaline structure across ocean fronts and their relation to sea-air CO2 balance are also analyzed. From spring to autumn, the near shore waters act as a source of atmospheric CO2, while the rest of the shelf is a CO2 sink, leading to highly negative areal means of sea-air CO2 flux and DeltapCO2. DeltapCO2 and CO2 flux in spring reach values of -67 μatm and -7mmol·m-2·d-1 respectively, and are close to equilibrium in winter. Sea-air DeltapCO2 and Chl a over the shelf are negatively correlated, suggesting that photosynthesis is one of the main processes responsible for the large CO2 sequestration. The annual areal mean DeltapCO2 and sea-air CO2 flux balance are -31μatm and -3.7mmol·m-2·d-1 respectively. The CO2 flux corresponds to 1.7 · 10-2 GT C yr-1 which is about 1% of the global ocean’s net annual CO2 uptake, almost 4 times the mean CO2 sink of the global ocean. Thus, the Patagonia Sea is one of the strongest CO2 sinks per unit area in the World Ocean.