Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 8, issue 1
Biogeosciences, 8, 165–174, 2011
https://doi.org/10.5194/bg-8-165-2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 8, 165–174, 2011
https://doi.org/10.5194/bg-8-165-2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 24 Jan 2011

Research article | 24 Jan 2011

Twentieth century δ13C variability in surface water dissolved inorganic carbon recorded by coralline algae in the northern North Pacific Ocean and the Bering Sea

B. Williams1, J. Halfar1, R. S. Steneck2, U. G. Wortmann3, S. Hetzinger1,*, W. Adey4, P. Lebednik5, and M. Joachimski6 B. Williams et al.
  • 1Department of Chemical and Physical Sciences, University of Toronto, Mississauga, Ontario, Canada
  • 2Darling Marine Center, University of Maine, Walpole, Maine, USA
  • 3Department of Geology, University of Toronto, Mississauga, Ontario, Canada
  • 4Department of Botany, Smithsonian Institution, Washington, D.C., USA
  • 5ARCADIS US Inc., Walnut Creek, California, USA
  • 6Institut für Geologie und Mineralogie, Universität Erlangen, Erlangen, Germany
  • *current address: IFM-GEOMAR, Leibniz Institute of Marine Sciences, Kiel, Germany

Abstract. The oxygen isotopic composition and Mg/Ca ratios in the skeletons of long-lived coralline algae record ambient seawater temperature over time. Similarly, the carbon isotopic composition in the skeletons record δ13C values of ambient seawater dissolved inorganic carbon. Here, we measured δ13C in the coralline alga Clathromorphum nereostratum to test the feasibility of reconstructing the intrusion of anthropogenic CO2 into the northern North Pacific Ocean and Bering Sea. The δ13C was measured in the high Mg-calcite skeleton of three C. nereostratum specimens from two islands 500 km apart in the Aleutian archipelago. In the records spanning 1887 to 2003, the average decadal rate of decline in δ13C values increased from 0.03‰ yr−1 in the 1960s to 0.095‰ yr−1 in the 1990s, which was higher than expected due to solely the δ13C-Suess effect. Deeper water in this region exhibits higher concentrations of CO2 and low δ13C values. Transport of deeper water into surface water (i.e., upwelling) increases when the Aleutian Low is intensified. We hypothesized that the acceleration of the δ13C decline may result from increased upwelling from the 1960s to 1990s, which in turn was driven by increased intensity of the Aleutian Low. Detrended δ13C records also varied on 4–7 year and bidecadal timescales supporting an atmospheric teleconnection of tropical climate patterns to the northern North Pacific Ocean and Bering Sea manifested as changes in upwelling.

Publications Copernicus
Download
Citation
Final-revised paper
Preprint