The silicon stable isotope distribution along the GEOVIDE section (GEOTRACES GA-01) of the North Atlantic Ocean

• Published in: Biogeosciences
• Main Authors: Sutton, Jill N., Souza, Gregory F. de, García-Ibáñez, Maribel I., Rocha, Christina L. de la
• Other Authors: Ministerio de Economía y Competitividad (España)
• Format: Article in Journal/Newspaper
• Language: English
• Published: European Geosciences Union 2018
• Subjects: Arctic; Arctic Ocean; Southern Ocean; Labrador Sea; North Atlantic
• Online Access: http://hdl.handle.net/10261/171015; https://doi.org/10.5194/bg-15-5663-2018; https://doi.org/10.13039/501100003329

14 pages, 6 figures, 3 tables.-- This work is distributed under the Creative Commons Attribution 4.0 License The stable isotope composition of dissolved silicon in seawater ( 30SiDSi) was examined at 10 stations along the GEOVIDE section (GEOTRACES GA-01), spanning the North Atlantic Ocean (40–60 N) and Labrador Sea. Variations in 30SiDSi below 500m were closely tied to the distribution of water masses. Higher 30SiDSi values are associated with intermediate and deep water masses of northern Atlantic or Arctic Ocean origin, whilst lower 30SiDSi values are associated with DSi-rich waters sourced ultimately from the Southern Ocean. Correspondingly, the lowest 30SiDSi values were observed in the deep and abyssal eastern North Atlantic, where dense southern-sourced waters dominate. The extent to which the spreading of water masses influences the 30SiDSi distribution is marked clearly by Labrador Sea Water (LSW), whose high 30SiDSi signature is visible not only within its region of formation within the Labrador and Irminger seas, but also throughout the mid-depth western and eastern North Atlantic Ocean. Both 30SiDSi and hydrographic parameters document the circulation of LSW into the eastern North Atlantic, where it overlies southern-sourced Lower DeepWater. The GEOVIDE 30SiDSi distribution thus provides a clear view of the direct interaction between subpolar/ polar water masses of northern and southern origin, and allow examination of the extent to which these far-field signals influence the local 30SiDSi distribution This work was supported by the “Laboratoire d’Excellence” LabexMER (ANR-10-LABX-19) and co-funded by a grant from the French government under the program “Investissements d’Avenir”, and by a grant from the Regional Council of Brittany (SAD programme). The GEOVIDE project was funded by CNRS-INSU (programme LEFE-CYBER), the French National Research Agency (ANR-13-BS06-0014, ANR-12-PDOC-0025-01) and “RPDOC” BITMAP (ANR-12-PDOC-0025), the LabexMER ANR-10-LABX-19) and Ifremer. The GEOVIDE project was ...