1 Comptes Rendus Geoscience Achimer November-December 2015, Volume 347 (7-8), Pages 377-385 http://dx.doi.org/10.1016/j.crte.2015.04.005 http://archimer.ifremer.fr http://archimer.ifremer.fr/doc/00273/38402/ © 2015 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved. Iron isotope systematics in Arctic rivers Escoube Raphaelle 1, 2, 9, Rouxel Olivier J. 2, 3, *, Pokrovsky Oleg S. 4, 5, 6, Schroth Andrew 7, Max Holmes Robert 8, Donard Olivier F.X. 1 1 LCABIE, Université de Pau et des pays de l’Adour, CNRS UMR 525, Hélioparc, 64053 Pau, France 2 Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, MA 02543 Woods Hole, USA 3 IFREMER, REM/GM, Centre de Brest, Plouzané, France 4 Georesources and Environment Toulouse GET, UMR 5563, CNRS, Université Paul-Sabatier, 31400 Toulouse, France 5 Institute of Ecological Problems of the North, Ural Branch RAS, Arkhangelsk, Russia 6 BIO-GEO-CLIM Laboratory, Tomsk State University, Tomsk, Russia 7 Department of Geology, University of Vermont, VT05405 Burlington, USA 8 Woods Hole Research Center, 02540 Falmouth, MA, USA 9 Universität zu Köln, Institut für Geologie und Mineralogie, Zülpicher Str. 49b, 50674 Köln, Germany * Corresponding author : Olivier J. Rouxel, email address :
[email protected] Abstract : The input of iron to the Arctic Ocean plays a critical role in the productivity of aquatic ecosystems and is potentially impacted by climate change. We examine Fe isotope systematics of dissolved and colloidal Fe from several Arctic and sub-Arctic rivers in northern Eurasia and Alaska. We demonstrate that the Fe isotopic (δ56Fe) composition of large rivers, such as the Ob’ and Lena, has a restricted range of δ56Fe values ca.–0.11 ± 0.13‰, with minimal seasonal variability, in stark contrast to smaller organic-rich rivers with an overall δ56Fe range from–1.7 to + 1.6‰.