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Strong margin influence on the Arctic Ocean barium cycle revealed by Pan-Arctic synthesis
  • +13
  • Laura M. Whitmore,
  • Alan M. Shiller,
  • Tristan J Horner,
  • Yang Xiang,
  • Maureen E Auro,
  • Dorothea Bauch,
  • Frank Dehairs,
  • Phoebe J. Lam,
  • JINGXUAN LI,
  • Maria Teresa Maldonado,
  • Chantal Mears,
  • Robert Newton,
  • Angelica Pasqualini,
  • Hélène Planquette,
  • Robert Rember,
  • Helmuth Thomas
Laura M. Whitmore
University of Southern Mississippi

Corresponding Author:[email protected]

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Alan M. Shiller
University of Southern Mississippi
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Tristan J Horner
Woods Hole Oceanographic Institution
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Yang Xiang
Department of Ocean Sciences, University of California at Santa Cruz
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Maureen E Auro
Woods Hole Oceanographic Institution
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Dorothea Bauch
University Kiel
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Frank Dehairs
Vrije Universiteit Brussel (AMGC)
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Phoebe J. Lam
University of California, Santa Cruz
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JINGXUAN LI
Woods Hole Oceanographic Institution
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Maria Teresa Maldonado
University of British Columbia
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Chantal Mears
Institute for Coastal Research, Helmholtz Centre Geesthacht
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Robert Newton
Columbia University
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Angelica Pasqualini
Columbia University
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Hélène Planquette
French National Centre for Scientific Research (CNRS)
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Robert Rember
International Arctic Research Center, University of Alaska Fairbanks
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Helmuth Thomas
Institute for Coastal Research, Helmholtz Center Geesthacht
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Abstract

What controls the distribution of barium (Ba) in the oceans? Answers to this question have been sought since early studies revealed relationships between particulate Ba (pBa) and POC and dissolved Ba (dBa) and silicate, suggesting applications for Ba as a paleoproductivity tracer and as a tracer of modern ocean circulation. Herein, we investigated the Arctic Ocean Ba cycle through a one-of-a-kind data set containing dissolved (dBa), particulate (pBa), and stable isotope Ba (δ138Ba) data from four Arctic GEOTRACES expeditions conducted in 2015. We hypothesized that margins would be a substantial source of Ba to the Arctic Ocean water column. The dBa, pBa, and δ138Ba distributions all suggest significant modification of inflowing Pacific seawater over the shelves, and the dBa mass balance implies that ~50% of the dBa inventory (upper 500 m of the Arctic water column) is not supplied by conservatively advected inputs. Calculated areal dBa fluxes are up to 10 µmol m-2 d-1 on the margin, which is comparable to fluxes described in other regions. Applying this approach to dBa data from the 1994 Arctic Ocean Survey yields similar results. Surprisingly, the Canadian Arctic Archipelago did not appear to have a similar margin source; rather, the dBa distribution in this section is consistent with mixing of Arctic Ocean-derived waters and Baffin-bay derived waters. Although we lack enough information to identify the specifics of the shelf sediment Ba source, we suspect that a terrigenous source (e.g., submarine groundwater discharge or fluvial particles) is an important contributor
Apr 2022Published in Journal of Geophysical Research: Oceans volume 127 issue 4. 10.1029/2021JC017417