Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 8, issue 6
Biogeosciences, 8, 1551–1564, 2011
https://doi.org/10.5194/bg-8-1551-2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 8, 1551–1564, 2011
https://doi.org/10.5194/bg-8-1551-2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 17 Jun 2011

Research article | 17 Jun 2011

Sources of short-lived bromocarbons in the Iberian upwelling system

S. Raimund1, B. Quack2, Y. Bozec1, M. Vernet1, V. Rossi3, V. Garçon3, Y. Morel4, and P. Morin1 S. Raimund et al.
  • 1CNRS-UPMC Univ Paris 06, UMR 7144, Adaptation et Diversité en Milieu Marin, Equipe Chimie Marine, Station Biologique de Roscoff, 29682 Roscoff, France
  • 2Department of Marine Biogeochemistry, Leibniz-Institute of Marine Science, Kiel, Germany
  • 3Laboratoire d'Etudes en Geophysique et Oceanographie Spatiales, CNRS, Toulouse, France
  • 4Service Hydrographique et Océanographique de la Marine, (SHOM), Toulouse, France

Abstract. Seawater concentrations of the four brominated trace gases, dibromomethane (CH2Br2), bromodichloromethane (CHBrCl2), dibromochloromethane (CHBr2Cl) and bromoform (CHBr3) were measured at different depths of the water column in the Iberian upwelling off Portugal during summer 2007. Statistical analysis of the data set revealed three distinct clusters, caused by different sea surface temperature. Bromocarbon concentrations were elevated in recently upwelled and aged upwelled waters (mean values of 30 pmol l−1 for CHBr3), while concentrations in the open ocean were significantly lower (7.4 pmol l−1 for CHBr3). Comparison with other productive marine areas revealed that the Iberian upwelling had higher halocarbon concentrations than the Mauritanian upwelling. However, the concentrations off the Iberian Peninsula were still much lower than those of coastal macroalgal-influenced waters or those of Polar regions dominated by cold water adapted diatoms. Correlations with biological variables and marker pigments indicated that phytoplankton was a source of bromocarbon in the open ocean. By contrast, in upwelled water masses along the coast, halocarbons showed weaker correlations to marker pigments but were significantly influenced by the tidal frequency. Our results indicate a strong intertidal coastal source of bromocarbon and transport by surface currents of these enriched waters towards the upwelling region.

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