Articles | Volume 9, issue 9
Biogeosciences, 9, 3679–3692, 2012

Special issue: How changes in ice cover, permafrost and UV radiation impact...

Biogeosciences, 9, 3679–3692, 2012

Research article 27 Sep 2012

Research article | 27 Sep 2012

Carbon fluxes in the Canadian Arctic: patterns and drivers of bacterial abundance, production and respiration on the Beaufort Sea margin

E. Ortega-Retuerta1,2,*, W. H. Jeffrey3, M. Babin4,5, S. Bélanger6, R. Benner7, D. Marie8, A. Matsuoka4,5, P. Raimbault9,10, and F. Joux1,2 E. Ortega-Retuerta et al.
  • 1UPMC Univ Paris 06, UMR7621, Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, 66650 Banyuls/mer, France
  • 2CNRS, UMR7621, Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, 66650 Banyuls/mer, France
  • 3Center for Environmental Diagnostics and Bioremediation, University of West Florida, Pensacola, FL, USA
  • 4Laboratoire d'Océanographie de Villefranche, UMR7093, Université Pierre et Marie Curie (Paris 6)/Centre National de la Recherche Scientifique (CNRS), B.P. 08, Port de la Darse, Villefranche-sur-Mer Cedex, 06230, France
  • 5Takuvik Joint International Laboratory, Université Laval (Canada) – CNRS (France), Département de Biologie and Québec-Océan, Université Laval, Pavillon Alexandre-Vachon 1045, avenue de la Médecine, Local 2078, G1V 0A6, Canada
  • 6Departement de Biologie, Chimie et Géographie, Université du Québec à Rimouski, Rimouski, Quebec, G5L 3A1, Canada
  • 7Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
  • 8CNRS, UMR7144 and UPMC (Paris 6), Station Biologique de Roscoff, Place G. Teissier, 29680 Roscoff, France
  • 9Aix-Marseille Univ., Mediterranean Institute of Oceanography (MIO), 13288, Marseille, Cedex 09, France
  • 10Université du Sud Toulon-Var, MIO, 83957, La Garde cedex, France
  • *present address: Institut de Ciències del Mar, CSIC 08003, Barcelona, Spain

Abstract. During August 2009, measurements of bacterial abundance and nucleic acid content were made along with production and respiration in coastal waters of the Beaufort Sea (Arctic Ocean), an area influenced by the Mackenzie River inflow. The main purpose was to evaluate bacterial organic carbon processing with respect to local sources, mainly primary production and river inputs. Bacterial production and abundance generally decreased from river to offshore waters and from surface to deep waters. In contrast, the percentage of high nucleic acid bacteria was higher in deep waters rather than in surface or river waters. Statistical analyses indicated that bacterial production was primarily controlled by temperature and the availability of labile organic matter, as indicated by total dissolved amino acid concentrations. Direct comparisons of bacterial carbon demand and primary production indicated net heterotrophy was common in shelf waters. Net autotrophy was observed at stations in the Mackenzie River plume, suggesting that the carbon fixed in plume waters helped fuel net heterotrophy in the Beaufort Sea margin.

Final-revised paper