The Transpolar Drift as a Source of Riverine and Shelf‐Derived Trace Elements to the Central Arctic Ocean
Matthew A. Charette, Lauren Kipp, Laramie T. Jensen, Jessica S. Dabrowski, Laura M. Whitmore, Jessica N. Fitzsimmons, Tatiana Williford, Adam Ulfsbo, Elizabeth M. Jones, Randelle M. Bundy, Sebastián M. Vivancos, Katharina Pahnke, Seth G. John, Yang Xiang, Mariko Hatta, Mariia V. Petrova, Lars‐Éric Heimbürger‐Boavida, Dorothea Bauch, R. Newton, Angelica Pasqualini, Alison M. Agather, Rainer M. W. Amon, Robert F. Anderson, Per Andersson, Ronald Benner, Katlin L. Bowman, R. Lawrence Edwards, Sandra Gdaniec, Loes J. A. Gerringa, Aridane G. González, Mats A. Granskog, Brian A. Haley, Chad R. Hammerschmidt, Dennis A. Hansell, Paul B. Henderson, David Kadko, Karl Kaiser, Patrick Laan, Phoebe J. Lam, Carl H. Lamborg, Martin Levier, Xianglei Li, Andrew R. Margolin, C. I. Measures, Rob Middag, Frank J. Millero, Willard S. Moore, Ronja Paffrath, Hélène Planquette, Benjamin Rabe, Heather E. Reader, Robert Rember, Micha J.A. Rijkenberg, Matthieu Roy‐Barman, Michiel M Rutgers van der Loeff, Mak A. Saito, Ursula Schauer, Peter Schlösser, Robert M. Sherrell, Alan M. Shiller, Hans Slagter, Jeroen E. Sonke, Colin A. Stedmon, Ryan J. Woosley, Ole Valk, Jan van Ooijen, Ruifeng Zhang
Abstract
Abstract A major surface circulation feature of the Arctic Ocean is the Transpolar Drift (TPD), a current that transports river‐influenced shelf water from the Laptev and East Siberian Seas toward the center of the basin and Fram Strait. In 2015, the international GEOTRACES program included a high‐resolution pan‐Arctic survey of carbon, nutrients, and a suite of trace elements and isotopes (TEIs). The cruises bisected the TPD at two locations in the central basin, which were defined by maxima in meteoric water and dissolved organic carbon concentrations that spanned 600 km horizontally and ~25–50 m vertically. Dissolved TEIs such as Fe, Co, Ni, Cu, Hg, Nd, and Th, which are generally particle‐reactive but can be complexed by organic matter, were observed at concentrations much higher than expected for the open ocean setting. Other trace element concentrations such as Al, V, Ga, and Pb were lower than expected due to scavenging over the productive East Siberian and Laptev shelf seas. Using a combination of radionuclide tracers and ice drift modeling, the transport rate for the core of the TPD was estimated at 0.9 ± 0.4 Sv (10 6 m 3 s −1 ). This rate was used to derive the mass flux for TEIs that were enriched in the TPD, revealing the importance of lateral transport in supplying materials beneath the ice to the central Arctic Ocean and potentially to the North Atlantic Ocean via Fram Strait. Continued intensification of the Arctic hydrologic cycle and permafrost degradation will likely lead to an increase in the flux of TEIs into the Arctic Ocean.