Air-sea CO2 fluxes in the Atlantic as measured during the FICARAM cruises

• Published in: Biogeosciences
• Main Authors: Padín, X.A. (Xosé Antonio), Vázquez-Rodríguez, M. (Marcos), Castaño-Carrera, M. (Mónica), Velo, A. (Antón), Alonso-Pérez, F. (Fernando), Gago, J. (Jesús), Gilcoto, M. (Miguel), Álvarez, M. (Marta), Conde-Pardo, P. (Paula), Paz, M. (Mercedes) de la, Fernández-Ríos, A. (Aida), Fernández-Pérez, F. (Fiz)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Centro Oceanográfico de Vigo 2010
• Subjects: Drake Passage; Southern Ocean; North Atlantic
• Online Access: http://hdl.handle.net/10508/1680; https://doi.org/10.5194/bg-7-1587-2010

A total of fourteen hydrographic cruises spanning from 2000 to 2008 were conducted during the spring and autumn seasons between Spain and the Southern Ocean, under the framework of the Spanish research project FICARAM. The performed underway measurements are processed and analysed to describe the meridional air-sea CO2 fluxes (F CO2) along the Atlantic Ocean. The data was organised into different biogeochemical oceanographic provinces, according mainly to the thermohaline characteristics. The obtained spatial and temporal distributions of F CO2 follow the generally expected patterns and annual trends. The Subtropical regions in both hemispheres alternated the CO2 source and sink nature from autumn to spring, respectively. On the other hand, Tropical waters and the Patagonian Sea clearly behaved as sinks of atmospheric CO2 like the waters of the Drake Passage during autumn. The obtained results during the cruises also revealed significant long-term trends, such as the warming of equatorial waters (0.11±0.03 Cyr−1) and the decrease of surface salinity (−0.16±0.01 yr−1) in tropical waters caused by the influence of the Amazon River plume. This reduction in surface salinity appears to have a direct influence over the CO2 storage rates, fostering the uptake capacity of atmospheric CO2 (−0.09±0.03 molm−2 yr−1). An analysis of the biogeochemical forcing on the CO2 fugacity (fCO2) variability performed from an empirical algorithm highlighted the major role of the Amazon River input in the tropical North Atlantic fluxes. In addition, it has provided a quantitative measure of the importance of the thermodynamic control of F CO2 at temperate latitudes.