Particulate Trace Element Export in the North Atlantic (GEOTRACES GA01 Transect, GEOVIDE Cruise)

• Published in: ACS Earth and Space Chemistry
• Main Authors: Lemaitre, Nolwenn, Planquette, Hélène, Dehairs, Frank, Planchon, Frédéric, Sarthou, Géraldine, Gallinari, Morgane, Roig, Stéphane, Catherine, Jeandel, Castrillejo, Maxi
• Other Authors: Institute of Geochemistry and Petrology ETH Zürich, Department of Earth Sciences Swiss Federal Institute of Technology - ETH Zürich (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Analytical, Environmental and Geo- Chemistry, Vrije Universiteit Brussel (VUB), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Ion Beam Physics ETH Zürich, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich), ANR-13-BS06-0014,GEOVIDE,GEOVIDE, Une étude internationale GEOTRACES le long de la section OVIDE en Atlantique Nord et en Mer du Labrador(2013), ANR-12-PDOC-0025,BITMAP,Biodisponibilité du fer et des métaux traces dans les particules marines(2012), ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: particulate trace elements; export fluxes; ACL; GEOTRACES; residence times; multiple carrier phases; envir; geo; Canada; Greenland; Labrador Sea; North Atlantic
• Online Access: https://doi.org/10.1021/acsearthspacechem.0c00045; https://hal.archives-ouvertes.fr/hal-03030236/file/Lemaitre_etal_ACS-EaSC_2020.pdf; https://hal.archives-ouvertes.fr/hal-03030236

International audience Vertical export of particulate trace elements (pTEs) is a critically underconstrained aspect of their biogeochemistry. Here, we combine elemental analyses on large (>53 μm) particles and 234Th measurements to determine downward export fluxes from the upper layers (40-110 m) of pTEs (Al, Cd, Co, Cu, Fe, Mn, Ni, P, Ti, V, Zn) and mineral phases (lithogenic, Fe-and Mn-oxides, calcium carbonate, and opal) in the North Atlantic along the GEOVIDE transect (Portugal-Greenland-Canada; GEOTRACES GA01 cruise). The role of lithogenic particles in controlling TE fluxes is obvious at proximity of the Iberian margin where the highest pTE export fluxes were estimated (up to 3912 μg/m2/d for pFe). However, high lithogenic and pTE fluxes are also observed up to 1700 km off this margin in the west European and Icelandic basins (up to 931 μg/m2/d for pFe). The lowest pTE export fluxes are determined in the Labrador Sea (as low as 501 μg/m2/d for pFe). High Mn-and Fe-oxide fluxes are estimated at the open ocean stations, suggesting that authigenic particles are an important vector of pTEs. All along the transect, biogenic particles also drive the pTE export fluxes, as shown by the similar pTE/POC ratios between exports and phytoplankton quotas. The shortest residence times (dissolved + particulate) are generally observed where lithogenic particles control the pTE fluxes (as low as 2 days for Fe) whereas pTEs seem to be longer retained when the contribution of biogenic particles become greater (residence times up to 147 days for Fe).