HAL : hal-00662988, version 1

Code Bibliographique ADS : 2011JGRC..11600G08T

DOI : 10.1029/2011JC007120

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Journal of Geophysical Research 116 (2011) C00G08

Barium and carbon fluxes in the Canadian Arctic Archipelago

Helmuth Thomas 1, Elizabeth Shadwick 1, Frank Dehairs 2, Bruno LANSARD 3, Alfonso Mucci 4, Jacques Navez 5, Yves Gratton 6, Friederike Prowe 7, Melissa Chierici 8, Agneta Fransson 9, Tim N. Papakyriakou 10, Erika Sternberg 1, Lisa A. Miller 11, Jean-Éric Tremblay 12, Christophe Monnin 13

(12/2011)

The seasonal and spatial variability of dissolved Barium (Ba) in the Amundsen Gulf, southeastern Beaufort Sea, was monitored over a full year from September 2007 to September 2008. Dissolved Ba displays a nutrient-type behavior: the maximum water column concentration is located below the surface layer. The highest Ba concentrations are typically observed at river mouths, the lowest concentrations are found in water masses of Atlantic origin. Barium concentrations decrease eastward through the Canadian Arctic Archipelago. Barite (BaSO4) saturation is reached at the maximum dissolved Ba concentrations in the subsurface layer, whereas the rest of the water column is undersaturated. A three end-member mixing model comprising freshwater from sea-ice melt and rivers, as well as upper halocline water, is used to establish their relative contributions to the Ba concentrations in the upper water column of the Amundsen Gulf. Based on water column and riverine Ba contributions, we assess the depletion of dissolved Ba by formation and sinking of biologically bound Ba (bio-Ba), from which we derive an estimate of the carbon export production. In the upper 50 m of the water column of the Amundsen Gulf, riverine Ba accounts for up to 15% of the available dissolved Ba inventory, of which up to 20% is depleted by bio-Ba formation and export. Since riverine inputs and Ba export occur concurrently, the seasonal variability of dissolved Ba in the upper water column is moderate. Assuming a fixed organic carbon to bio-Ba flux ratio, carbon export out of the surface layer is estimated at 1.8 ± 0.45 mol C m‑2 yr‑1. Finally, we propose a climatological carbon budget for the Amundsen Gulf based on recent literature data and our findings, the latter bridging the surface and subsurface water carbon cycles.

1 :	Department of Oceanography
	Dalhousie University
2 :	Earth System Sciences and Analytical and Environmental Chemistry
	Vrije Universiteit Brussel
3 :	Laboratoire d'Océanographie et de Biogéochimie
	Aucune
4 :	GEOTOP and Department of Earth and Planetary Sciences
	McGill University
5 :	Geology and mineralogy, section of Mineralogy and Petrography
	Royal Museum for Central Africa
6 :	INRS‐ETE
	INRS‐ETE
7 :	IFM-GEOMAR
	Leibniz-Institut für Meereswissenschaften
8 :	Department of Chemistry
	University of Gothenburg
9 :	Department of Earth Sciences
	University of Gothenburg
10 :	Center for Earth Observation Science,
	University of Manitoba
11 :	Institute of Ocean Sciences, Fisheries and Oceans Canada,
	Institute of Ocean Sciences, Fisheries and Oceans Canada
12 :	Department de Biologie
	Universite Laval, Quebec
13 :	Laboratoire des Mécanismes et Transfert en Géologie (LMTG)
	CNRS : UMR5563 – Observatoire Midi-Pyrénées – Université Paul Sabatier [UPS] - Toulouse III – Institut de recherche pour le développement [IRD] : UMR154

Domaine

:

Planète et Univers/Sciences de la Terre/Géochimie Sciences de l'environnement/Milieux et Changements globaux

Mots Clés : Biogeosciences: Biogeochemical cycles – processes – and modeling (0412 – 0793 – 1615 – 4805 – 4912) – Biogeosciences: Carbon cycling (4806) – Biogeosciences: Diel – seasonal – and annual cycles (4227) – Biogeosciences: Trace element cycling (4875) – Oceanography: Biological and Chemical: Marine inorganic chemistry (1050)

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Contributeur : Christophe Monnin <>

Soumis le : Mercredi 25 Janvier 2012, 17:03:13

Dernière modification le : Vendredi 27 Janvier 2012, 16:14:05