Rare earth elements in the North Atlantic, part I: Non-conservative behavior reveals margin inputs and deep waters scavenging

• Published in: Chemical Geology
• Main Authors: Lagarde, Marion, Pham, Viet, Quoc, Lherminier, Pascale, Belhadj, Moustafa, Jeandel, Catherine
• Other Authors: 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 et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X), Institut Polytechnique de Paris (IP Paris)-Institut Polytechnique de Paris (IP Paris)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X), Institut Polytechnique de Paris (IP Paris)-Institut Polytechnique de Paris (IP Paris)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institute of Environmental Technology Hanoi (IET), Vietnam Academy of Science and Technology (VAST), This research has been supported by the French National Research Agency (grant ANR-13-BS06-0014, ANR-12-PDOC-0025-01), the French National Centre for Scientific Research (grant CNRS-LEFE-CYBER), the LabexMER (grant ANR-10-LABX-19), and Ifremer. It was supported in the logistics by DT-INSU and GENAVIR. The International GEOTRACES Programme is possible in part thanks to the support from the U.S. National Science Foundation (Grant OCE-2140395) to the Scientific Committee on Oceanic Research (SCOR)., ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2024
• Subjects: Boundary exchange; dREE; GEOTRACES; GEOVIDE; Iberian margin; Margin inputs; Nepheloid layers; Non-conservative behavior; [SDE]Environmental Sciences; Iceland; North Atlantic; North East Atlantic
• Online Access: https://hal.univ-brest.fr/hal-04690693; https://hal.univ-brest.fr/hal-04690693/document; https://hal.univ-brest.fr/hal-04690693/file/1-s2.0-S0009254124003103-main.pdf; https://doi.org/10.1016/j.chemgeo.2024.122230

International audience Dissolved concentrations of 14 Rare Earth Elements (dREE) were measured in seawater samples collected during the GEOVIDE cruise (GEOTRACES GA01, May-June 2014) in the North Atlantic. This is the first dREE dataset produced using the manually operated self-built preconcentration system, made of eight columns of Nobias chelate PA-1® resin (Hitachi High-Technologies) in parallel. Concentration profiles differ from the typical "nutrient-like" dREE vertical distributions. Instead, we observe surface enrichment, especially close to the Iberian margin, and constant or decreasing concentrations below 500 m. An extended Optimum Multiparameter Analysis applied to the GEOVIDE section allowed disentangling the conservative signal brought by water masses from the non-conservative signal produced by inputs or subtractions along the water pathways. Results show i) strong dissolved inputs from the Iberian margin from resuspended particle dissolution, ii) that surprisingly, rather than mixing, scavenging in deep water masses is responsible for the decreasing concentrations at depth, especially in the lower North East Atlantic Deep Water and the Iceland Scotland Overflow Water, and iii) that in the Irminger and Labrador Seas, biological uptake is compensated by external inputs. The combination of lithogenic inputs from the Iberian margin, due to partial dissolution, with scavenging in deep water masses supports that mechanisms occurring at the land-ocean interface explain part of the observations of boundary exchange.