Oxygen isotopes in marine diatoms: a comparative study of analytical techniques and new results on the isotope fractionation during phytoplankton growth
Oxygen isotope analyses of marine diatoms were performed in two independent ways. Stepwise fluorination of hydrous opal-A results in plateau δ180 values representing the isotopic composition of the silica frame oxygen. A method of controlled isotope exchange before silica dehydration also produces r...
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ftoceanrep:oai:oceanrep.geomar.de:11652 2023-05-15T14:08:52+02:00 Oxygen isotopes in marine diatoms: a comparative study of analytical techniques and new results on the isotope fractionation during phytoplankton growth Schmidt, Mark Botz , R. Stoffers , P. Anders , T. Bohrmann , Gerhard 1997 text https://oceanrep.geomar.de/id/eprint/11652/ https://oceanrep.geomar.de/id/eprint/11652/1/M.Schmidt.pdf https://doi.org/10.1016/S0016-7037(97)00081-1 en eng Elsevier https://oceanrep.geomar.de/id/eprint/11652/1/M.Schmidt.pdf Schmidt, M. , Botz , R., Stoffers , P., Anders , T. and Bohrmann , G. (1997) Oxygen isotopes in marine diatoms: a comparative study of analytical techniques and new results on the isotope fractionation during phytoplankton growth. Geochimica et Cosmochimica Acta, 61 . pp. 2275-2280. DOI 10.1016/S0016-7037(97)00081-1 <https://doi.org/10.1016/S0016-7037%2897%2900081-1>. doi:10.1016/S0016-7037(97)00081-1 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 1997 ftoceanrep https://doi.org/10.1016/S0016-7037(97)00081-1 2023-04-07T14:59:51Z Oxygen isotope analyses of marine diatoms were performed in two independent ways. Stepwise fluorination of hydrous opal-A results in plateau δ180 values representing the isotopic composition of the silica frame oxygen. A method of controlled isotope exchange before silica dehydration also produces reliable results, although the exchangeability of the silica was variable. Consequently, a calibration of the isotope exchange method using the results from stepwise fluorination experiments is very useful (and sometimes essential) in order to select a water vapor of an appropriate isotopic composition to be used for equilibration. Sediment diatom samples Ethmodiscus rex and Thalassiothrix longissima from the Antarctic and the North Atlantic Ocean, respectively, show strong 180 enrichments of 46.8 and 44.1‰, which are caused by large isotope fractionation occurring at the low temperature prevailing during silica-water isotope exchange reactions. However, phytoplankton samples from surface waters of the Norwegian-Greenland Sea and the Bellingshausen Sea (Antarctica) have δ180 values between 30.4 and 35.0‰. Thus, the true silica-water isotopic fractionation is approximately 3 to 10‰ lower than the temperature-dependent silica-water equilibrium published in the literature for sedimentary diatoms. Our results indicate that successive isotope exchange reactions of diatomaceous silica with ambient seawater and/or pore water determine the isotope values of diatoms in sediments. Article in Journal/Newspaper Antarc* Antarctic Antarctica Bellingshausen Sea Greenland Greenland Sea North Atlantic OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Antarctic Bellingshausen Sea Greenland The Antarctic Geochimica et Cosmochimica Acta 61 11 2275 2280 |
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Open Polar |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
English |
description |
Oxygen isotope analyses of marine diatoms were performed in two independent ways. Stepwise fluorination of hydrous opal-A results in plateau δ180 values representing the isotopic composition of the silica frame oxygen. A method of controlled isotope exchange before silica dehydration also produces reliable results, although the exchangeability of the silica was variable. Consequently, a calibration of the isotope exchange method using the results from stepwise fluorination experiments is very useful (and sometimes essential) in order to select a water vapor of an appropriate isotopic composition to be used for equilibration. Sediment diatom samples Ethmodiscus rex and Thalassiothrix longissima from the Antarctic and the North Atlantic Ocean, respectively, show strong 180 enrichments of 46.8 and 44.1‰, which are caused by large isotope fractionation occurring at the low temperature prevailing during silica-water isotope exchange reactions. However, phytoplankton samples from surface waters of the Norwegian-Greenland Sea and the Bellingshausen Sea (Antarctica) have δ180 values between 30.4 and 35.0‰. Thus, the true silica-water isotopic fractionation is approximately 3 to 10‰ lower than the temperature-dependent silica-water equilibrium published in the literature for sedimentary diatoms. Our results indicate that successive isotope exchange reactions of diatomaceous silica with ambient seawater and/or pore water determine the isotope values of diatoms in sediments. |
format |
Article in Journal/Newspaper |
author |
Schmidt, Mark Botz , R. Stoffers , P. Anders , T. Bohrmann , Gerhard |
spellingShingle |
Schmidt, Mark Botz , R. Stoffers , P. Anders , T. Bohrmann , Gerhard Oxygen isotopes in marine diatoms: a comparative study of analytical techniques and new results on the isotope fractionation during phytoplankton growth |
author_facet |
Schmidt, Mark Botz , R. Stoffers , P. Anders , T. Bohrmann , Gerhard |
author_sort |
Schmidt, Mark |
title |
Oxygen isotopes in marine diatoms: a comparative study of analytical techniques and new results on the isotope fractionation during phytoplankton growth |
title_short |
Oxygen isotopes in marine diatoms: a comparative study of analytical techniques and new results on the isotope fractionation during phytoplankton growth |
title_full |
Oxygen isotopes in marine diatoms: a comparative study of analytical techniques and new results on the isotope fractionation during phytoplankton growth |
title_fullStr |
Oxygen isotopes in marine diatoms: a comparative study of analytical techniques and new results on the isotope fractionation during phytoplankton growth |
title_full_unstemmed |
Oxygen isotopes in marine diatoms: a comparative study of analytical techniques and new results on the isotope fractionation during phytoplankton growth |
title_sort |
oxygen isotopes in marine diatoms: a comparative study of analytical techniques and new results on the isotope fractionation during phytoplankton growth |
publisher |
Elsevier |
publishDate |
1997 |
url |
https://oceanrep.geomar.de/id/eprint/11652/ https://oceanrep.geomar.de/id/eprint/11652/1/M.Schmidt.pdf https://doi.org/10.1016/S0016-7037(97)00081-1 |
geographic |
Antarctic Bellingshausen Sea Greenland The Antarctic |
geographic_facet |
Antarctic Bellingshausen Sea Greenland The Antarctic |
genre |
Antarc* Antarctic Antarctica Bellingshausen Sea Greenland Greenland Sea North Atlantic |
genre_facet |
Antarc* Antarctic Antarctica Bellingshausen Sea Greenland Greenland Sea North Atlantic |
op_relation |
https://oceanrep.geomar.de/id/eprint/11652/1/M.Schmidt.pdf Schmidt, M. , Botz , R., Stoffers , P., Anders , T. and Bohrmann , G. (1997) Oxygen isotopes in marine diatoms: a comparative study of analytical techniques and new results on the isotope fractionation during phytoplankton growth. Geochimica et Cosmochimica Acta, 61 . pp. 2275-2280. DOI 10.1016/S0016-7037(97)00081-1 <https://doi.org/10.1016/S0016-7037%2897%2900081-1>. doi:10.1016/S0016-7037(97)00081-1 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/S0016-7037(97)00081-1 |
container_title |
Geochimica et Cosmochimica Acta |
container_volume |
61 |
container_issue |
11 |
container_start_page |
2275 |
op_container_end_page |
2280 |
_version_ |
1766280904012988416 |