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

Sutton, Jill N.; de Souza, Gregory F.; García-Ibáñez, Maribel I.; De La Rocha, Christina L.

The stable isotope composition of dissolved silicon in seawater (inline-formulaδ30SiDSi) was examined at 10 stations along the GEOVIDE section (GEOTRACES GA-01), spanning the North Atlantic Ocean (40–60inline-formula N) and Labrador Sea. Variations in inline-formulaδ30SiDSi below 500 m were closely tied to the distribution of water masses. Higher inline-formulaδ30SiDSi values are associated with intermediate and deep water masses of northern Atlantic or Arctic Ocean origin, whilst lower inline-formulaδ30SiDSi values are associated with DSi-rich waters sourced ultimately from the Southern Ocean. Correspondingly, the lowest inline-formulaδ30SiDSi 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 inline-formulaδ30SiDSi distribution is marked clearly by Labrador Sea Water (LSW), whose high inline-formulaδ30SiDSi 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 inline-formulaδ30SiDSi and hydrographic parameters document the circulation of LSW into the eastern North Atlantic, where it overlies southern-sourced Lower Deep Water. The GEOVIDE inline-formulaδ30SiDSi 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 inline-formulaδ30SiDSi distribution.



Sutton, Jill N. / de Souza, Gregory F. / García-Ibáñez, Maribel I. / et al: The silicon stable isotope distribution along the GEOVIDE section (GEOTRACES GA-01) of the North Atlantic Ocean. 2018. Copernicus Publications.


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