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

The stable isotope composition of dissolved silicon in seawater ( δ 30 Si DSi ) 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 δ 30 Si DSi below 500 m were closely tied to the distribution of water...

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Bibliographic Details
Published in:Biogeosciences
Main Authors: J. N. Sutton, G. F. de Souza, M. I. García-Ibáñez, C. L. De La Rocha
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2018
Subjects:
Ecology
QH540-549.5
Life
QH501-531
Geology
QE1-996.5
Arctic
Arctic Ocean
Southern Ocean
Labrador Sea
North Atlantic
Online Access:https://doi.org/10.5194/bg-15-5663-2018
https://doaj.org/article/2effc9e3973a4c44a600ee480d32ff4f
Description
Summary:The stable isotope composition of dissolved silicon in seawater ( δ 30 Si DSi ) 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 δ 30 Si DSi below 500 m were closely tied to the distribution of water masses. Higher δ 30 Si DSi values are associated with intermediate and deep water masses of northern Atlantic or Arctic Ocean origin, whilst lower δ 30 Si DSi values are associated with DSi-rich waters sourced ultimately from the Southern Ocean. Correspondingly, the lowest δ 30 Si DSi 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 δ 30 Si DSi distribution is marked clearly by Labrador Sea Water (LSW), whose high δ 30 Si DSi 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 δ 30 Si DSi and hydrographic parameters document the circulation of LSW into the eastern North Atlantic, where it overlies southern-sourced Lower Deep Water. The GEOVIDE δ 30 Si DSi 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 δ 30 Si DSi distribution.

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