FN Archimer Export Format PT J TI Strong margin influence on the Arctic Ocean barium cycle revealed by Pan-Arctic synthesis BT AF Whitmore, Laura M Shiller, Alan M Horner, Tristan J Xiang, Yang Auro, Maureen E Bauch, Dorothea Dehairs, Frank Lam, Phoebe J Li, Jingxuan Maldonado, Maria T Mears, Chantal Newton, Robert Pasqualini, Angelica PLANQUETTE, Helene Rember, Robert Thoams, Helmoth AS 1:1;2:1;3:2;4:3;5:2;6:4;7:5;8:3;9:6;10:6;11:7;12:8;13:9;14:10;15:11;16:7; FF 1:;2:;3:;4:;5:;6:;7:;8:;9:;10:;11:;12:;13:;14:;15:;16:; C1 School of Ocean Science and Engineering, University of Southern Mississippi, Stennis Space Center, Mississippi, USA NIRVANA Laboratories, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA Department of Ocean Sciences, University of California, Santa Cruz, CA 95064 USA GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany Analytical, Environmental and Geochemistry, Vrije Universiteit Brussel, 1050 Brussels, Belgium Earth Ocean & Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada Institute of Carbon Cycles, Helmholtz Centre Hereon, D-21502 Geesthacht, Germany Lamont-Doherty Earth Observatory, Columbia University, USA Department of Earth and Environmental Engineering, Columbia University, New York, NY, USA Univ Brest, CNRS, IRD, Ifremer, LEMAR, F-29280 Plouzane, France International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA C2 UNIV SOUTHERN MISSISSIPPI, USA WHOI, USA UNIV CALIF SANTA CRUZ, USA IFM GEOMAR, GERMANY UNIV VRIJE BRUSSEL, BELGIUM UNIV BRITISH COLUMBIA, CANADA HZG, GERMANY UNIV COLUMBIA, USA UNIV COLUMBIA, USA CNRS, FRANCE UNIV ALASKA FAIRBANKS, USA UM LEMAR IN WOS Cotutelle UMR copubli-europe copubli-int-hors-europe IF 3.6 TC 6 UR https://archimer.ifremer.fr/doc/00760/87213/92684.pdf https://archimer.ifremer.fr/doc/00760/87213/92685.pdf LA English DT Article DE ;GEOTRACES;barium isotopes;geochemical cycles;climate;continental shelves AB Early studies revealed relationships between barium (Ba), particulate organic carbon and silicate, suggesting applications for Ba as a paleoproductivity tracer and as a tracer of modern ocean circulation. But, what controls the distribution of barium (Ba) in the oceans? 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 ratio (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) was supplied by nonconservative 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. 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 sedimentary remineralization and terrigenous sources (e.g., submarine groundwater discharge or fluvial particles) are contributors. Plain Language Summary We investigated the barium cycle in the Arctic Ocean. The oceanic barium cycle is supported by the interplay of seawater mixing, river inputs, sediment inputs, and particle formation and export from the water column. We determined that the distribution of dissolved barium in the upper 500 m of the Arctic Ocean is largely set by a shelf sediment source; this is newly described, as previous literature assumed rivers and seawater mixing were the predominant contributors to the distribution. This discovery fits in with recent findings that the shelf sediments are a major source of radium and other trace metals to the surface Arctic Ocean. This is important to consider as the warming climate continues to erode Arctic ice cover (sea ice or glacial). Monitoring the relative sources of Ba to the water column can help define how warming impacts Arctic Ocean biogeochemistry. PY 2022 PD APR SO Journal Of Geophysical Research-oceans SN 2169-9275 PU American Geophysical Union VL 127 IS 4 UT 000777613200001 DI 10.1029/2021JC017417 ID 87213 ER EF