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Paper in press: Margins matter for the Arctic barium budget

What controls the distribution of dissolved barium in the Arctic? This is the question we tried to answer in a recent study led by Laura Whitmore. The study integrates measurements of dissolved and particulate barium and barium isotope compositions measured on samples collected during four GEOTRACES Arctic expeditions in 2015—GN01, GN02, GN03, and GN04 (HLY1502, ArcticNet 1502, ArcticNet 1503, and PS94, respectively). What did we find?

  1. The mass balance of barium in the Arctic is seriously out of steady state, with margin sources accounting for up to 50 % of the barium budget in the upper 500 m of the water column.
  2. The margin barium flux appears to be sourced from the dissolution of particles on the shelf, rather than terrestrial barium sources.
  3. Despite most profiles from the Amerasian Arctic Ocean exhibiting ‘inverted’ barium isotope profiles, the samples still fall (mostly) on the global mixing array.

These findings and many more discussed in the paper!

Full citation: Whitmore, L.M., A.M. Shiller, T.J. Horner, Y. Xiang, M.E. Auro, D. Bauch, F. Dehairs, P.J. Lam, J. Li, M.T. Maldonado, C. Mears, R. Newton, A. Pasqualini, H. Planquette, R. Rember, and H. Thomas (2022). Strong Margin Influence on the Arctic Ocean Barium Cycle Revealed by Pan-Arctic Synthesis. Journal of Geophysical Research: Oceans, 127(4), e2021JC017417, doi:10.1029/2021JC017417.