Foraminifera Iodine to Calcium Ratios: Approach and Cleaning
Planktic and benthic foraminiferal iodine (I) to calcium (Ca) molar ratios have been proposed as an exciting new proxy to assess subsurface and bottom water oxygenation in the past. Compared to trace metals, the analysis of iodine in foraminiferal calcite is more challenging, as iodine is volatile i...
Published in: | Geochemistry, Geophysics, Geosystems |
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Main Authors: | , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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Wiley
2021
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Online Access: | https://hdl.handle.net/20.500.12866/10202 https://doi.org/10.1029/2021GC009811 |
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ftuperucayetanoh:oai:repositorio.upch.edu.pe:20.500.12866/10202 2023-05-15T18:01:08+02:00 Foraminifera Iodine to Calcium Ratios: Approach and Cleaning Winkelbauer, H. Cordova-Rodriguez, K. Reyes-Macaya, D. Scott, J. Glock, N. Lu, Z. Hamilton, E. Chenery, S. Holdship, P. Dormon, C. Hoogakker, B. 2021 https://hdl.handle.net/20.500.12866/10202 https://doi.org/10.1029/2021GC009811 eng eng Wiley urn:issn:1525-2027 https://hdl.handle.net/20.500.12866/10202 https://doi.org/10.1029/2021GC009811 info:eu-repo/semantics/restrictedAccess https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es CC-BY-NC-ND Amines Ammonia Ammonium hydroxide Benthic and planktic foraminifer I/calcium benthic and planktic foraminifera I/Ca benthic foraminifera calcite calcium Calcium carbonate Cleaning cleaning method Cleaning methods environmental samples (Foraminifera) Foraminifera Foraminifers iodine iodine stabilization Molar ratio Organic carbon oxygenation Planktic foraminifera planktonic foraminifera Sample sizes Stabilization Tertiary amine Tetramethyl ammonium hydroxide Trace elements trace metal info:eu-repo/semantics/article 2021 ftuperucayetanoh https://doi.org/20.500.12866/10202 https://doi.org/10.1029/2021GC009811 2022-08-14T07:02:02Z Planktic and benthic foraminiferal iodine (I) to calcium (Ca) molar ratios have been proposed as an exciting new proxy to assess subsurface and bottom water oxygenation in the past. Compared to trace metals, the analysis of iodine in foraminiferal calcite is more challenging, as iodine is volatile in acid solution. Here, we compare previous analyses that use tertiary amine with alternative analyses using tetramethylammonium hydroxide (TMAH) and ammonium hydroxide (NH4OH) to stabilize iodine in solution. In addition, we assess the effect of sample size and cleaning on planktic and benthic foraminiferal I/Ca. Our stabilization experiments with TMAH and NH4OH show similar trends as those using tertiary amine, giving relatively low I/Ca ratios for planktic and benthic foraminifera samples from poorly oxygenated waters, and high ratios for well-oxygenated waters. This suggests that both alternative methods are suitable to stabilize iodine initially dissolved in acid. Samples that contain 5–10 specimens show a wide spread in I/Ca. Samples containing 20 specimens or more show more centered I/Ca values, indicating that a larger sample size is more representative of the average planktic foraminifera community. The impact of cleaning on planktic and benthic foraminifera I/Ca ratios is very similar to Mg/Ca, with the largest effect occurring during the clay removal step. The largest iodine contaminations were recorded at locations characterized by moderate to high organic carbon contents. In those circumstances, we recommend doubling the oxidative cleaning steps (4 instead of 2 repetitions) to ensure that all organic material is removed Article in Journal/Newspaper Planktonic foraminifera Repositorio Institucional de la UPCH (Universidad Peruana Cayetano Heredia) Geochemistry, Geophysics, Geosystems 22 11 |
institution |
Open Polar |
collection |
Repositorio Institucional de la UPCH (Universidad Peruana Cayetano Heredia) |
op_collection_id |
ftuperucayetanoh |
language |
English |
topic |
Amines Ammonia Ammonium hydroxide Benthic and planktic foraminifer I/calcium benthic and planktic foraminifera I/Ca benthic foraminifera calcite calcium Calcium carbonate Cleaning cleaning method Cleaning methods environmental samples (Foraminifera) Foraminifera Foraminifers iodine iodine stabilization Molar ratio Organic carbon oxygenation Planktic foraminifera planktonic foraminifera Sample sizes Stabilization Tertiary amine Tetramethyl ammonium hydroxide Trace elements trace metal |
spellingShingle |
Amines Ammonia Ammonium hydroxide Benthic and planktic foraminifer I/calcium benthic and planktic foraminifera I/Ca benthic foraminifera calcite calcium Calcium carbonate Cleaning cleaning method Cleaning methods environmental samples (Foraminifera) Foraminifera Foraminifers iodine iodine stabilization Molar ratio Organic carbon oxygenation Planktic foraminifera planktonic foraminifera Sample sizes Stabilization Tertiary amine Tetramethyl ammonium hydroxide Trace elements trace metal Winkelbauer, H. Cordova-Rodriguez, K. Reyes-Macaya, D. Scott, J. Glock, N. Lu, Z. Hamilton, E. Chenery, S. Holdship, P. Dormon, C. Hoogakker, B. Foraminifera Iodine to Calcium Ratios: Approach and Cleaning |
topic_facet |
Amines Ammonia Ammonium hydroxide Benthic and planktic foraminifer I/calcium benthic and planktic foraminifera I/Ca benthic foraminifera calcite calcium Calcium carbonate Cleaning cleaning method Cleaning methods environmental samples (Foraminifera) Foraminifera Foraminifers iodine iodine stabilization Molar ratio Organic carbon oxygenation Planktic foraminifera planktonic foraminifera Sample sizes Stabilization Tertiary amine Tetramethyl ammonium hydroxide Trace elements trace metal |
description |
Planktic and benthic foraminiferal iodine (I) to calcium (Ca) molar ratios have been proposed as an exciting new proxy to assess subsurface and bottom water oxygenation in the past. Compared to trace metals, the analysis of iodine in foraminiferal calcite is more challenging, as iodine is volatile in acid solution. Here, we compare previous analyses that use tertiary amine with alternative analyses using tetramethylammonium hydroxide (TMAH) and ammonium hydroxide (NH4OH) to stabilize iodine in solution. In addition, we assess the effect of sample size and cleaning on planktic and benthic foraminiferal I/Ca. Our stabilization experiments with TMAH and NH4OH show similar trends as those using tertiary amine, giving relatively low I/Ca ratios for planktic and benthic foraminifera samples from poorly oxygenated waters, and high ratios for well-oxygenated waters. This suggests that both alternative methods are suitable to stabilize iodine initially dissolved in acid. Samples that contain 5–10 specimens show a wide spread in I/Ca. Samples containing 20 specimens or more show more centered I/Ca values, indicating that a larger sample size is more representative of the average planktic foraminifera community. The impact of cleaning on planktic and benthic foraminifera I/Ca ratios is very similar to Mg/Ca, with the largest effect occurring during the clay removal step. The largest iodine contaminations were recorded at locations characterized by moderate to high organic carbon contents. In those circumstances, we recommend doubling the oxidative cleaning steps (4 instead of 2 repetitions) to ensure that all organic material is removed |
format |
Article in Journal/Newspaper |
author |
Winkelbauer, H. Cordova-Rodriguez, K. Reyes-Macaya, D. Scott, J. Glock, N. Lu, Z. Hamilton, E. Chenery, S. Holdship, P. Dormon, C. Hoogakker, B. |
author_facet |
Winkelbauer, H. Cordova-Rodriguez, K. Reyes-Macaya, D. Scott, J. Glock, N. Lu, Z. Hamilton, E. Chenery, S. Holdship, P. Dormon, C. Hoogakker, B. |
author_sort |
Winkelbauer, H. |
title |
Foraminifera Iodine to Calcium Ratios: Approach and Cleaning |
title_short |
Foraminifera Iodine to Calcium Ratios: Approach and Cleaning |
title_full |
Foraminifera Iodine to Calcium Ratios: Approach and Cleaning |
title_fullStr |
Foraminifera Iodine to Calcium Ratios: Approach and Cleaning |
title_full_unstemmed |
Foraminifera Iodine to Calcium Ratios: Approach and Cleaning |
title_sort |
foraminifera iodine to calcium ratios: approach and cleaning |
publisher |
Wiley |
publishDate |
2021 |
url |
https://hdl.handle.net/20.500.12866/10202 https://doi.org/10.1029/2021GC009811 |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_relation |
urn:issn:1525-2027 https://hdl.handle.net/20.500.12866/10202 https://doi.org/10.1029/2021GC009811 |
op_rights |
info:eu-repo/semantics/restrictedAccess https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/20.500.12866/10202 https://doi.org/10.1029/2021GC009811 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
22 |
container_issue |
11 |
_version_ |
1766170474467819520 |