First measurements of the ocean-atmosphere CO2 fluxes at the Cabo Frio upwelling system region, Southwestern Atlantic Ocean

This study presents novel results about ocean-atmosphere CO2 exchanges based upon novel direct in situ measurements of turbulent fluxes using the eddy covariance (EC) methodology. This study was carried out on the Southeast coast of Brazil and the adjacent open ocean during two days of the austral winter of 2015, on board the RV Vital de Oliveira. This is the first time that the EC technique was used in this region for CO2 flux studies. The results presented illustrate contrasting magnitudes of CO 2 fluxes measured on the open sea region (1.22 +/- 2.08 mu mol m(-2) s(-1)), the Brazil Current (-2.92 +/- 1.25 mu mol m(-2) s(-1)) and the coastal region ( -3.11 +/- 1.67 mu mol m(-2) s(-1)). The main cause of negative CO2 fluxes, indicating a mean CO2 sink behavior of this region, is due to the occurrence of the coastal upwelling phenomenon and the atmospheric conditions. We found that lower atmosphere local modulation due to sea surface temperature (SST) variations along the study region combined with the large-scale atmospheric synoptic conditions contributed to the flux behavior.