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Air-Sea CO2 fluxes in the Atlantic as measured during boreal spring and autumn

Citation

Padin, XA and Vazquez-Rodriguez, M and Castano, M and Velo, A and Alonso-Perez, F and Gago, J and Gilcoto, M and Alvarez, M and Pardo, PC and de la Paz, M and Rios, AF and Perez, FF, Air-Sea CO2 fluxes in the Atlantic as measured during boreal spring and autumn, Biogeosciences, 7, (5) pp. 1587-1606. ISSN 1726-4170 (2010) [Refereed Article]


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Copyright 2010 The Authors. Licensed under Creative Commons Attribution 3.0 Unported (CC BY 3.0) http://creativecommons.org/licenses/by/3.0/

DOI: doi:10.5194/bg-7-1587-2010

Abstract

A total of fourteen hydrographic cruises 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 underway measurements were processed and analysed to describe the meridional air-sea CO2 fluxes (FCO2) in the covered sector of the Atlantic Ocean. The data has been grouped into different biogeochemical oceanographic provinces based on thermohaline characteristics. The spatial and temporal distributions of FCO2 followed expected distributions and annual trends reproducing the recent climatological ΔfCO2 estimations with a mean difference of −3 ± 18 μatm (Takahashi et al., 2009). The reduction in the CO2 saturation along the meridional FICARAM cruises represented an increase of 0.02 ± 0.14 mol m−2 yr−1 in the ocean uptake of atmospheric CO2. The subtropical waters in both Hemispheres acted as a sink of atmospheric CO2 during the successive spring seasons and as a source in autumn. The coarse reduction of the ocean uptake of atmospheric CO2 observed in the North Atlantic Ocean was linked to conditions of negative phase of the North Atlantic Oscillation that prevailed during the FICARAM period. Surface waters in the North Equatorial Counter Current revealed a significant long-term decrease of sea surface salinity of −0.16 ± 0.01 yr−1 coinciding with a declination of −3.5 ± 0.9 μatm yr−1 in the air–sea disequilibrium of CO2 fugacity and a rise of oceanic CO2 uptake of −0.09 ± 0.03 mol m−2 yr−1. The largest CO2 source was located in the equatorial upwelling system. These tropical waters that reached emissions of 0.7 ± 0.5 and 1.0 ± 0.7 mol m−2 y−1 in spring and autumn, respectively, showed an interannual warming of 0.11 ± 0.03 °C yr−1 and a wind speed decrease of −0.58 ± 0.14 m s−1 yr−1 in spring cruises which suggest the weakening of upwelling events associated with warm El Niño – Southern Oscillation episodes. Contrary the surface waters of the Patagonian Sea behaved as an intense sink of CO2 in March and November. The oceanic waters of the convergence of Falkland and Brazil Currents showed the strongest CO2 absorption with a rate of −5.4 ± 3.6 mol m−2 yr−1 in November. The Southern Oceans sampled in the Drake Passage behave as an average uptake rate of −1.1 ± 0.9 mol m−2 yr−1 while the distal shelf of the Livingston Island acted as a slight source of CO2 to the atmosphere.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Physical Geography and Environmental Geoscience
Research Field:Surface Processes
Objective Division:Environment
Objective Group:Physical and Chemical Conditions of Water
Objective Field:Physical and Chemical Conditions of Water in Marine Environments
UTAS Author:Pardo, PC (Dr Paula Conde Pardo)
ID Code:103047
Year Published:2010
Web of Science® Times Cited:21
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2015-09-16
Last Modified:2015-10-12
Downloads:321 View Download Statistics

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