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

Abstract

Sea-air differences of CO2 partial pressures (△pCO 2) and surface chlorophyll α (chl-α) 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 CO 2 flux and △pCO2. The △pCO2 and CO2 flux in spring reach values of -67 μatm and -7 x 10 -3 mol m-2 d-1, respectively, and are close to equilibrium in winter. Sea-air △pCO2 and chl-α 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 △pCO2 and sea-air CO2 flux are -31 μatm and -3.7 x 10-3 mol m-2 d-1, respectively, indicating that the Patagonia Sea is one of the strongest CO 2 sinks per unit area in the World Ocean. Copyright 2009 by the American Geophysical Union.