Controls on Dissolved Silicon Isotopes Along the U.S. GEOTRACES Eastern Pacific Zonal Transect (GP16)
The distribution of dissolved silicon isotopes (δ30Si) was examined along the U.S. GEOTRACES East Pacific Zonal Transect (GP16) extending from Peru to Tahiti (10°S and 15°S latitude). Surface waters in the subtropical gyre displayed high δ30Si due to strong utilization of silicic acid (DSi). In cont...
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ftdatacite:10.23689/fidgeo-5032 2023-05-15T13:44:15+02:00 Controls on Dissolved Silicon Isotopes Along the U.S. GEOTRACES Eastern Pacific Zonal Transect (GP16) Grasse, P. Closset, I. Jones, J. L. Geilert, S. Brzezinski, M. A. 2020 https://dx.doi.org/10.23689/fidgeo-5032 https://e-docs.geo-leo.de/handle/11858/9378 en eng FID GEO Text Article article-journal ScholarlyArticle 2020 ftdatacite https://doi.org/10.23689/fidgeo-5032 2021-11-05T12:55:41Z The distribution of dissolved silicon isotopes (δ30Si) was examined along the U.S. GEOTRACES East Pacific Zonal Transect (GP16) extending from Peru to Tahiti (10°S and 15°S latitude). Surface waters in the subtropical gyre displayed high δ30Si due to strong utilization of silicic acid (DSi). In contrast, surface waters close to the Peruvian coast where upwelling prevailed were less depleted and only moderately fractionated. δ30Si of water masses along the transect was compared with the results of an Optimum Multiparameter Analysis that quantified the fractional contributions of end-member water masses in each sample. Strong admixture of intermediate waters obscured the expected heavy isotopic signatures of Subantarctic Mode Water and Antarctic Intermediate Water. Isotope values were nearly homogenous below 2,000 m (average: +1.3 ± 0.1‰, 1 s.d.) despite the 25 μmol kg−1 range in the DSi content among water masses. This homogeneity confirms prior observations and model results that predict nearly constant δ30Si values of +1.0‰ to +1.2‰ for Pacific deep waters with [DSi] > 100 μmol kg−1. Waters above the East Pacific Rise (EPR) influenced by hydrothermal activity showed a small increase in [DSi] together with dissolved iron, but overall stations close to the EPR were slightly depleted in [DSi] (3 to 6 μmol kg−1) with no significant shift in δ30Si compared to adjacent waters. Hydrothermal [DSi] appears to precipitate within the conduit of the EPR or upon contact with cold seawater resulting in a negligible influence of hydrothermal fluids on δ30Si in deep water. Text Antarc* Antarctic DataCite Metadata Store (German National Library of Science and Technology) Antarctic Pacific |
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Open Polar |
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DataCite Metadata Store (German National Library of Science and Technology) |
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ftdatacite |
language |
English |
description |
The distribution of dissolved silicon isotopes (δ30Si) was examined along the U.S. GEOTRACES East Pacific Zonal Transect (GP16) extending from Peru to Tahiti (10°S and 15°S latitude). Surface waters in the subtropical gyre displayed high δ30Si due to strong utilization of silicic acid (DSi). In contrast, surface waters close to the Peruvian coast where upwelling prevailed were less depleted and only moderately fractionated. δ30Si of water masses along the transect was compared with the results of an Optimum Multiparameter Analysis that quantified the fractional contributions of end-member water masses in each sample. Strong admixture of intermediate waters obscured the expected heavy isotopic signatures of Subantarctic Mode Water and Antarctic Intermediate Water. Isotope values were nearly homogenous below 2,000 m (average: +1.3 ± 0.1‰, 1 s.d.) despite the 25 μmol kg−1 range in the DSi content among water masses. This homogeneity confirms prior observations and model results that predict nearly constant δ30Si values of +1.0‰ to +1.2‰ for Pacific deep waters with [DSi] > 100 μmol kg−1. Waters above the East Pacific Rise (EPR) influenced by hydrothermal activity showed a small increase in [DSi] together with dissolved iron, but overall stations close to the EPR were slightly depleted in [DSi] (3 to 6 μmol kg−1) with no significant shift in δ30Si compared to adjacent waters. Hydrothermal [DSi] appears to precipitate within the conduit of the EPR or upon contact with cold seawater resulting in a negligible influence of hydrothermal fluids on δ30Si in deep water. |
format |
Text |
author |
Grasse, P. Closset, I. Jones, J. L. Geilert, S. Brzezinski, M. A. |
spellingShingle |
Grasse, P. Closset, I. Jones, J. L. Geilert, S. Brzezinski, M. A. Controls on Dissolved Silicon Isotopes Along the U.S. GEOTRACES Eastern Pacific Zonal Transect (GP16) |
author_facet |
Grasse, P. Closset, I. Jones, J. L. Geilert, S. Brzezinski, M. A. |
author_sort |
Grasse, P. |
title |
Controls on Dissolved Silicon Isotopes Along the U.S. GEOTRACES Eastern Pacific Zonal Transect (GP16) |
title_short |
Controls on Dissolved Silicon Isotopes Along the U.S. GEOTRACES Eastern Pacific Zonal Transect (GP16) |
title_full |
Controls on Dissolved Silicon Isotopes Along the U.S. GEOTRACES Eastern Pacific Zonal Transect (GP16) |
title_fullStr |
Controls on Dissolved Silicon Isotopes Along the U.S. GEOTRACES Eastern Pacific Zonal Transect (GP16) |
title_full_unstemmed |
Controls on Dissolved Silicon Isotopes Along the U.S. GEOTRACES Eastern Pacific Zonal Transect (GP16) |
title_sort |
controls on dissolved silicon isotopes along the u.s. geotraces eastern pacific zonal transect (gp16) |
publisher |
FID GEO |
publishDate |
2020 |
url |
https://dx.doi.org/10.23689/fidgeo-5032 https://e-docs.geo-leo.de/handle/11858/9378 |
geographic |
Antarctic Pacific |
geographic_facet |
Antarctic Pacific |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_doi |
https://doi.org/10.23689/fidgeo-5032 |
_version_ |
1766199459314663424 |