Variation in calcification of Reticulofenestra coccoliths over the Oligocene-Early Miocene
Coccolithophores are calcifying marine phytoplankton whose intracellularly produced calcite plates, coccoliths, have been the dominant source of calcium carbonate in open-ocean settings since the Cretaceous. An open question is whether their calcification has been affected by changing environmental...
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ftethz:oai:www.research-collection.ethz.ch:20.500.11850/582967 2023-05-15T17:22:39+02:00 Variation in calcification of Reticulofenestra coccoliths over the Oligocene-Early Miocene Guitián, José Fuertes, Miguel Ángel Flores, José-Abel Hernández-Almeida, Iván Stoll, Heather 2022 application/application/pdf https://hdl.handle.net/20.500.11850/582967 https://doi.org/10.3929/ethz-b-000582967 en eng Copernicus info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-19-5007-2022 info:eu-repo/grantAgreement/SNF/Projekte MINT/182070 http://hdl.handle.net/20.500.11850/582967 doi:10.3929/ethz-b-000582967 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International CC-BY Biogeosciences, 19 (20) info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2022 ftethz https://doi.org/20.500.11850/582967 https://doi.org/10.3929/ethz-b-000582967 https://doi.org/10.5194/bg-19-5007-2022 2023-02-13T01:15:22Z Coccolithophores are calcifying marine phytoplankton whose intracellularly produced calcite plates, coccoliths, have been the dominant source of calcium carbonate in open-ocean settings since the Cretaceous. An open question is whether their calcification has been affected by changing environmental conditions over geological timescales such as variations in the ocean carbon system. Previous methods using circular polarized light microscopy allowed for only the thickness of small coccoliths thinner than 1.5 μm to be quantified, but prior to the Pliocene, a significant fraction of the coccoliths exceeded this thickness and have not been quantifiable. Here, we implement a new approach for calibration of circular polarized light microscopy enabling us to quantify coccoliths which feature calcite up to 3 μm thick. We apply this technique to evaluate the evolution of calcification in the Reticulofenestra from the early Oligocene to Early Miocene in exceptionally well-preserved sediments from the Newfoundland margin. Through this time interval, coccolith thickness and the scale-invariant shape factor kse vary by about 20% around the mean thickness of 0.37 μm and mean kse of 0.16. Lower shape factors characterize samples with a higher relative abundance of dissolution-resistant nannoliths, suggesting that dissolution may contribute to thinning of placoliths. We therefore define temporal trends in calcification only in samples in which the assemblage suggests minimal dissolution. The lowest kse characterizes the middle Oligocene, and the highest kse around 18Ma is in the Early Miocene. High ocean dissolved inorganic carbon (DIC) concentrations have been proposed for this period of the Miocene and may be one factor contributing to high coccolith kse. ISSN:1726-4170 ISSN:1726-4170 Article in Journal/Newspaper Newfoundland ETH Zürich Research Collection |
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Open Polar |
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ETH Zürich Research Collection |
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ftethz |
language |
English |
description |
Coccolithophores are calcifying marine phytoplankton whose intracellularly produced calcite plates, coccoliths, have been the dominant source of calcium carbonate in open-ocean settings since the Cretaceous. An open question is whether their calcification has been affected by changing environmental conditions over geological timescales such as variations in the ocean carbon system. Previous methods using circular polarized light microscopy allowed for only the thickness of small coccoliths thinner than 1.5 μm to be quantified, but prior to the Pliocene, a significant fraction of the coccoliths exceeded this thickness and have not been quantifiable. Here, we implement a new approach for calibration of circular polarized light microscopy enabling us to quantify coccoliths which feature calcite up to 3 μm thick. We apply this technique to evaluate the evolution of calcification in the Reticulofenestra from the early Oligocene to Early Miocene in exceptionally well-preserved sediments from the Newfoundland margin. Through this time interval, coccolith thickness and the scale-invariant shape factor kse vary by about 20% around the mean thickness of 0.37 μm and mean kse of 0.16. Lower shape factors characterize samples with a higher relative abundance of dissolution-resistant nannoliths, suggesting that dissolution may contribute to thinning of placoliths. We therefore define temporal trends in calcification only in samples in which the assemblage suggests minimal dissolution. The lowest kse characterizes the middle Oligocene, and the highest kse around 18Ma is in the Early Miocene. High ocean dissolved inorganic carbon (DIC) concentrations have been proposed for this period of the Miocene and may be one factor contributing to high coccolith kse. ISSN:1726-4170 ISSN:1726-4170 |
format |
Article in Journal/Newspaper |
author |
Guitián, José Fuertes, Miguel Ángel Flores, José-Abel Hernández-Almeida, Iván Stoll, Heather |
spellingShingle |
Guitián, José Fuertes, Miguel Ángel Flores, José-Abel Hernández-Almeida, Iván Stoll, Heather Variation in calcification of Reticulofenestra coccoliths over the Oligocene-Early Miocene |
author_facet |
Guitián, José Fuertes, Miguel Ángel Flores, José-Abel Hernández-Almeida, Iván Stoll, Heather |
author_sort |
Guitián, José |
title |
Variation in calcification of Reticulofenestra coccoliths over the Oligocene-Early Miocene |
title_short |
Variation in calcification of Reticulofenestra coccoliths over the Oligocene-Early Miocene |
title_full |
Variation in calcification of Reticulofenestra coccoliths over the Oligocene-Early Miocene |
title_fullStr |
Variation in calcification of Reticulofenestra coccoliths over the Oligocene-Early Miocene |
title_full_unstemmed |
Variation in calcification of Reticulofenestra coccoliths over the Oligocene-Early Miocene |
title_sort |
variation in calcification of reticulofenestra coccoliths over the oligocene-early miocene |
publisher |
Copernicus |
publishDate |
2022 |
url |
https://hdl.handle.net/20.500.11850/582967 https://doi.org/10.3929/ethz-b-000582967 |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
Biogeosciences, 19 (20) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-19-5007-2022 info:eu-repo/grantAgreement/SNF/Projekte MINT/182070 http://hdl.handle.net/20.500.11850/582967 doi:10.3929/ethz-b-000582967 |
op_rights |
info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/20.500.11850/582967 https://doi.org/10.3929/ethz-b-000582967 https://doi.org/10.5194/bg-19-5007-2022 |
_version_ |
1766109440351666176 |