Atmospheric aerosoldeposition fluxes over the Atlantic Ocean: A GEOTRACES case study

Type Article
Date 2019-04
Language English
Author(s) Menzel Barraqueta Jan-Lukas1, Klar Jessica K.2, 3, Gledhill Martha1, Schlosser Christian1, Shelley Rachel4, 5, 6, Planquette Helene5, Wenzel Bernhard1, Sarthou Geraldine5, Achterberg Eric P.1
Affiliation(s) 1 : GEOMAR, Helmholtz Centre for Ocean Research Kiel, Germany
2 : Ocean and Earth Science, National Oceanography Centre, University of Southampton, European Way, Southampton SO14 3ZH, UK
3 : LEGOS, Université de Toulouse, CNES, CNRS, IRD, UPS, 14 Avenue Edouard Belin, 31400 Toulouse, France
4 : Department of Earth, Ocean and Atmospheric Science, Florida State University, 117 N Woodward Ave, Tallahassee, Florida 32301, USA
5 : Laboratoire des Sciences de l’Environnement Marin, UMR 6539 LEMAR (CNRS/UBO/IRD/IFREMER), Institut Universitaire Européen de la Mer, Technopôle Brest-Iroise, Plouzané 29280, LEMAR, UMR 6539, Plouzané, France
6 : School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth, PL4 8AA, UK
Source Biogeosciences (1726-4189) (Copernicus GmbH), 2019-04 , Vol. 16 , N. 7 , P. 1525-1542
DOI 10.5194/bg-2018-209
Note Special issue GEOVIDE, an international GEOTRACES study along the OVIDE section in the North Atlantic and in the Labrador Sea (GA01) Editor(s): G. Henderson, C. Jeandel, M. Lohan, G. Reverdin, and L. Bopp
Abstract

Atmospheric deposition is an important source of micronutrients to the ocean, but atmospheric deposition fluxes remain poorly constrained in most ocean regions due to the limited number of field observations of wet and dry atmospheric inputs. Here we present the distribution of dissolved aluminium (dAl), as a tracer of atmospheric inputs, in surface waters of the Atlantic Ocean along GEOTRACES sections GA01, GA06, GA08, and GA10. We used the surface mixed layer concentrations of dAl to calculate atmospheric deposition fluxes using a simple steady state model. We have optimized the aerosol Al fractional solubility, dAl residence time within the surface mixed layer and depth of the surface mixed layer for each separate cruise to calculate the atmospheric deposition fluxes. We calculated the lowest deposition fluxes of 0.15 ± 0.1 and 0.27 ± 0.13 g m−2 yr−1 for the South and North Atlantic Ocean (> 40° S and > 40° N), respectively, and highest fluxes of 2.67 ± 1.96 and 3.82 ± 2.72 g m−2 yr−1 for the South East Atlantic and tropical Atlantic Ocean, respectively. Overall, our estimations are comparable to atmospheric dust deposition model estimates and reported field-based atmospheric deposition estimates. We note that our estimates diverge from atmospheric dust deposition model flux estimates in regions influenced by riverine Al inputs and in upwelling regions. As dAl is a key trace element in the GEOTRACES Programme, the approach presented in this study allows calculations of atmospheric deposition fluxes at high spatial resolution for remote ocean regions.

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Menzel Barraqueta Jan-Lukas, Klar Jessica K., Gledhill Martha, Schlosser Christian, Shelley Rachel, Planquette Helene, Wenzel Bernhard, Sarthou Geraldine, Achterberg Eric P. (2019). Atmospheric aerosoldeposition fluxes over the Atlantic Ocean: A GEOTRACES case study. Biogeosciences, 16(7), 1525-1542. Publisher's official version : https://doi.org/10.5194/bg-2018-209 , Open Access version : https://archimer.ifremer.fr/doc/00485/59675/