Aluminium in the North Atlantic Ocean and the Labrador Sea (GEOTRACES GA01 section): roles of continental inputs and biogenic particle removal

• Published in: Biogeosciences
• Main Authors: Menzel Barraqueta, Jan Lukas, Schlosser, Christian, Planquette, Hélène, Gourain, Arthur, Cheize, Marie, Boutorh, Julia, Shelley, Rachel U., Pereira Contreira, Leonardo, Gledhill, Martha, Hopwood, Mark J, Lacan, F., Lherminier, Pascale, Sarthou, Géraldine, Achterberg, Eric P.
• Other Authors: Helmholtz Centre for Ocean Research Kiel (GEOMAR), 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 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)-Centre National de la Recherche Scientifique (CNRS), Department of Earth Ocean and Ecological Sciences Liverpool, University of Liverpool, Department of Earth, Ocean and Atmospheric Science Tallahassee (FSU, Florida State University Tallahassee (FSU), School of Geography, Earth and Environmental Sciences Plymouth (SoGEES), Plymouth University, Universidade Federal do Rio Grande do Norte Natal (UFRN), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), ANR-12-PDOC-0025,BITMAP,Biodisponibilité du fer et des métaux traces dans les particules marines(2012), 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-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: DENMARK STRAIT OVERFLOW; FLOW-INJECTION ANALYSIS; DISSOLVED ALUMINUM; SURFACE WATERS; PARTICULATE ALUMINUM; COASTAL WATERS; ATMOSPHERIC DEPOSITION; SEDIMENT RESUSPENSION; DUST DEPOSITION; SOUTH-ATLANTIC; ACL; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; Greenland; Denmark Strait; Labrador Sea; North Atlantic
• Online Access: https://hal.science/hal-02322921; https://hal.science/hal-02322921/document; https://hal.science/hal-02322921/file/Menzel-Barraqueta_etal_BG_2018.pdf; https://doi.org/10.5194/bg-15-5271-2018

International audience The distribution of dissolved aluminium (dAl) in the water column of the North Atlantic and Labrador Sea was studied along GEOTRACES section GA01 to unravel the sources and sinks of this element. Surface water dAl concentrations were low (median of 2.5 nM) due to low aerosol deposition and removal by biogenic particles (i.e. phyto-plankton cells). However, surface water dAl concentrations were enhanced on the Iberian and Greenland shelves (up to 30.9 nM) due to continental inputs (rivers, glacial flour, and ice melt). Dissolved Al in surface waters scaled negatively with chlorophyll a and biogenic silica (opal) concentrations. The abundance of diatoms exerted a significant (p < 0.01) control on the surface particulate Al (pAl) to dAl ratios by decreasing dAl levels and increasing pAl levels. Dissolved Al concentrations generally increased with depth and correlated strongly with silicic acid (R 2 > 0.76) west of the Iberian Basin, suggesting net release of dAl at depth during reminer-alization of sinking opal-containing particles. Enrichment of dAl at near-bottom depths was observed due to the resus-pension of sediments. The highest dAl concentrations (up to 38.7 nM) were observed in Mediterranean Outflow Waters, which act as a major source of dAl to mid-depth waters of the eastern North Atlantic. This study clearly shows that the vertical and lateral distributions of dAl in the North Atlantic differ when compared to other regions of the Atlantic and global oceans. Responsible for these large inter-and intra-basin differences are the large spatial variabilities in the main Al source, atmospheric deposition, and the main Al sink, particle scavenging by biogenic particles.