Chromium isotopic composition of core‐top planktonic foraminifera
Abstract The chromium isotope system ( 53 Cr/ 52 Cr expressed as δ 53 Cr relative to NIST SRM 979) is potentially a powerful proxy for the redox state of the ocean–atmosphere system, but a lack of temporally continuous, well‐calibrated archives has limited its application to date. Marine carbonates...
Published in: | Geobiology |
---|---|
Main Authors: | , , , , , , |
Other Authors: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2016
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1111/gbi.12198 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fgbi.12198 https://onlinelibrary.wiley.com/doi/pdf/10.1111/gbi.12198 |
id |
crwiley:10.1111/gbi.12198 |
---|---|
record_format |
openpolar |
spelling |
crwiley:10.1111/gbi.12198 2024-06-23T07:56:16+00:00 Chromium isotopic composition of core‐top planktonic foraminifera Wang, X. L. Planavsky, N. J. Hull, P. M. Tripati, A. E. Zou, H. J. Elder, L. Henehan, M. Agouron Institute 2016 http://dx.doi.org/10.1111/gbi.12198 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fgbi.12198 https://onlinelibrary.wiley.com/doi/pdf/10.1111/gbi.12198 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Geobiology volume 15, issue 1, page 51-64 ISSN 1472-4677 1472-4669 journal-article 2016 crwiley https://doi.org/10.1111/gbi.12198 2024-06-06T04:21:38Z Abstract The chromium isotope system ( 53 Cr/ 52 Cr expressed as δ 53 Cr relative to NIST SRM 979) is potentially a powerful proxy for the redox state of the ocean–atmosphere system, but a lack of temporally continuous, well‐calibrated archives has limited its application to date. Marine carbonates could potentially serve as a common and continuous Cr isotope archive. Here, we present the first evaluation of planktonic foraminiferal calcite as an archive of seawater δ 53 Cr. We show that single foraminiferal species from globally distributed core tops yielded variable δ 53 Cr, ranging from 0.1‰ to 2.5‰. These values do not match with the existing measurements of seawater δ 53 Cr. Further, within a single core‐top, species with similar water column distributions (i.e., depth habitats) yielded variable δ 53 Cr values. In addition, mixed layer and thermocline species do not consistently exhibit decreasing trends in δ 53 Cr as expected based on current understanding of Cr cycling in the ocean. These observations suggest that either seawater δ 53 Cr is more heterogeneous than previously thought or that there is significant and species‐dependent Cr isotope fractionation during foraminiferal calcification. Given that the δ 53 Cr variability is comparable to that observed in geological samples throughout Earth's history, interpreting planktonic foraminiferal δ 53 Cr without calibrating modern foraminifera further, and without additional seawater measurements, would lead to erroneous conclusions. Our core‐top survey clearly indicates that planktonic foraminifera are not a straightforward δ 53 Cr archive and should not be used to study marine redox evolution without additional study. It likewise cautions against the use of δ 53 Cr in bulk carbonate or other biogenic archives pending further work on vital effects and the geographic heterogeneity of the Cr isotope composition of seawater. Article in Journal/Newspaper Planktonic foraminifera Wiley Online Library Geobiology 15 1 51 64 |
institution |
Open Polar |
collection |
Wiley Online Library |
op_collection_id |
crwiley |
language |
English |
description |
Abstract The chromium isotope system ( 53 Cr/ 52 Cr expressed as δ 53 Cr relative to NIST SRM 979) is potentially a powerful proxy for the redox state of the ocean–atmosphere system, but a lack of temporally continuous, well‐calibrated archives has limited its application to date. Marine carbonates could potentially serve as a common and continuous Cr isotope archive. Here, we present the first evaluation of planktonic foraminiferal calcite as an archive of seawater δ 53 Cr. We show that single foraminiferal species from globally distributed core tops yielded variable δ 53 Cr, ranging from 0.1‰ to 2.5‰. These values do not match with the existing measurements of seawater δ 53 Cr. Further, within a single core‐top, species with similar water column distributions (i.e., depth habitats) yielded variable δ 53 Cr values. In addition, mixed layer and thermocline species do not consistently exhibit decreasing trends in δ 53 Cr as expected based on current understanding of Cr cycling in the ocean. These observations suggest that either seawater δ 53 Cr is more heterogeneous than previously thought or that there is significant and species‐dependent Cr isotope fractionation during foraminiferal calcification. Given that the δ 53 Cr variability is comparable to that observed in geological samples throughout Earth's history, interpreting planktonic foraminiferal δ 53 Cr without calibrating modern foraminifera further, and without additional seawater measurements, would lead to erroneous conclusions. Our core‐top survey clearly indicates that planktonic foraminifera are not a straightforward δ 53 Cr archive and should not be used to study marine redox evolution without additional study. It likewise cautions against the use of δ 53 Cr in bulk carbonate or other biogenic archives pending further work on vital effects and the geographic heterogeneity of the Cr isotope composition of seawater. |
author2 |
Agouron Institute |
format |
Article in Journal/Newspaper |
author |
Wang, X. L. Planavsky, N. J. Hull, P. M. Tripati, A. E. Zou, H. J. Elder, L. Henehan, M. |
spellingShingle |
Wang, X. L. Planavsky, N. J. Hull, P. M. Tripati, A. E. Zou, H. J. Elder, L. Henehan, M. Chromium isotopic composition of core‐top planktonic foraminifera |
author_facet |
Wang, X. L. Planavsky, N. J. Hull, P. M. Tripati, A. E. Zou, H. J. Elder, L. Henehan, M. |
author_sort |
Wang, X. L. |
title |
Chromium isotopic composition of core‐top planktonic foraminifera |
title_short |
Chromium isotopic composition of core‐top planktonic foraminifera |
title_full |
Chromium isotopic composition of core‐top planktonic foraminifera |
title_fullStr |
Chromium isotopic composition of core‐top planktonic foraminifera |
title_full_unstemmed |
Chromium isotopic composition of core‐top planktonic foraminifera |
title_sort |
chromium isotopic composition of core‐top planktonic foraminifera |
publisher |
Wiley |
publishDate |
2016 |
url |
http://dx.doi.org/10.1111/gbi.12198 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fgbi.12198 https://onlinelibrary.wiley.com/doi/pdf/10.1111/gbi.12198 |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_source |
Geobiology volume 15, issue 1, page 51-64 ISSN 1472-4677 1472-4669 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/gbi.12198 |
container_title |
Geobiology |
container_volume |
15 |
container_issue |
1 |
container_start_page |
51 |
op_container_end_page |
64 |
_version_ |
1802649253574606848 |