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

[1] Sea-air differences of CO2 partial pressures (ΔpCO2) and surface chlorophyll a (chl-a) concentration have been determined during 22 cruises in various seasons for 2000–2006 over the Patagonia Sea and shelf break. From spring to autumn, the nearshore waters act as a source of atmospheric CO2, while the midshelf and slope are a CO2 sink, leading to highly negative areal means of sea-air CO2 flux and ΔpCO2. The ΔpCO2 and CO2 flux in spring reach values of −67 μatm and −7 × 10−3 mol m−2 d−1, respectively, and are close to equilibrium in winter. Sea-air ΔpCO2 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 ΔpCO2 and sea-air CO2 flux are −31 μatm and −3.7 × 10−3 mol m−2 d−1, respectively, indicating that the Patagonia Sea is one of the strongest CO2 sinks per unit area in the World Ocean.