Silicon stable isotope distribution traces Southern Ocean export of Si to the eastern South Pacific thermocline ...
The cycling and transport of dissolved silicon (Si) in the ocean may be traced by its stable isotope composition, δ30Si. We present a dataset of δ30Si values along 103° W in the eastern South Pacific Ocean, ranging from the Antarctic Zone of the Southern Ocean (62° S) to the equatorial Pacific (12°...
| Main Authors: | , , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
ETH Zurich
2012
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.3929/ethz-b-000062765 http://hdl.handle.net/20.500.11850/62765 |
| Summary: | The cycling and transport of dissolved silicon (Si) in the ocean may be traced by its stable isotope composition, δ30Si. We present a dataset of δ30Si values along 103° W in the eastern South Pacific Ocean, ranging from the Antarctic Zone of the Southern Ocean (62° S) to the equatorial Pacific (12° S). At high southern latitudes, the uptake and associated isotope fractionation of Si by diatoms results in highly elevated δ30Si values (up to +3.2‰) in the summer mixed layer. High δ30Si values (+2‰) are also preserved in the high-latitude fossil winter mixed layer, documenting the efficient export of diatom opal beyond the maximum depth of winter convection. This elevated winter mixed layer δ30Si signature is introduced into the ocean interior by the subduction of Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW), whose northward spreading results in a strong isopycnal control on lower-thermocline and intermediate δ30Si values in the well-ventilated eastern South Pacific. Values of δ30Si ... : Biogeosciences, 9 (11) ... |
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