Limited freshwater cap in the Eocene Arctic Ocean
Remains of the freshwater fern Azolla, found in Eocene (~50 Ma ago) sediments in the modern central Arctic Ocean, have been used to suggest that seasonal freshwater caps covered the entire Arctic Ocean during that time, with significant impact on global ocean circulation and climate. However, these...
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ftpubmed:oai:pubmedcentral.nih.gov:6414537 2023-05-15T14:37:41+02:00 Limited freshwater cap in the Eocene Arctic Ocean Neville, Lisa A. Grasby, Stephen E. McNeil, David H. 2019-03-12 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6414537/ http://www.ncbi.nlm.nih.gov/pubmed/30862936 https://doi.org/10.1038/s41598-019-40591-w en eng Nature Publishing Group UK http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6414537/ http://www.ncbi.nlm.nih.gov/pubmed/30862936 http://dx.doi.org/10.1038/s41598-019-40591-w © The Author(s) 2019 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. CC-BY Article Text 2019 ftpubmed https://doi.org/10.1038/s41598-019-40591-w 2019-03-17T01:23:38Z Remains of the freshwater fern Azolla, found in Eocene (~50 Ma ago) sediments in the modern central Arctic Ocean, have been used to suggest that seasonal freshwater caps covered the entire Arctic Ocean during that time, with significant impact on global ocean circulation and climate. However, these records are located on the Lomonosov Ridge, which during the Eocene was a continental fragment barely rifted from Eurasia, separating the smaller Eurasian Basin from the much larger Amerasian Basin to the west. As such, the Lomonosov Ridge does not necessarily record environmental conditions of the broader Arctic Ocean. We tested the hypothesis of freshwater caps by examining sediment records from the western Amerasian Basin. Here we show that in the larger Amerasian Basin the Azolla event is associated with marine microfauna along with allochthonous (terrestrially sourced) organic matter. We propose that Azolla events are related to an increased hydrologic cycle washing terrestrially sourced Azolla, and other organics, into the Arctic Ocean. If freshwater caps did occur, then they were at best restricted to the small Eurasian Basin and would have had a limited impact on Eocene global climate, contrary to current models. Text Arctic Arctic Ocean Lomonosov Ridge PubMed Central (PMC) Arctic Arctic Ocean Scientific Reports 9 1 |
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Article Neville, Lisa A. Grasby, Stephen E. McNeil, David H. Limited freshwater cap in the Eocene Arctic Ocean |
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Article |
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Remains of the freshwater fern Azolla, found in Eocene (~50 Ma ago) sediments in the modern central Arctic Ocean, have been used to suggest that seasonal freshwater caps covered the entire Arctic Ocean during that time, with significant impact on global ocean circulation and climate. However, these records are located on the Lomonosov Ridge, which during the Eocene was a continental fragment barely rifted from Eurasia, separating the smaller Eurasian Basin from the much larger Amerasian Basin to the west. As such, the Lomonosov Ridge does not necessarily record environmental conditions of the broader Arctic Ocean. We tested the hypothesis of freshwater caps by examining sediment records from the western Amerasian Basin. Here we show that in the larger Amerasian Basin the Azolla event is associated with marine microfauna along with allochthonous (terrestrially sourced) organic matter. We propose that Azolla events are related to an increased hydrologic cycle washing terrestrially sourced Azolla, and other organics, into the Arctic Ocean. If freshwater caps did occur, then they were at best restricted to the small Eurasian Basin and would have had a limited impact on Eocene global climate, contrary to current models. |
format |
Text |
author |
Neville, Lisa A. Grasby, Stephen E. McNeil, David H. |
author_facet |
Neville, Lisa A. Grasby, Stephen E. McNeil, David H. |
author_sort |
Neville, Lisa A. |
title |
Limited freshwater cap in the Eocene Arctic Ocean |
title_short |
Limited freshwater cap in the Eocene Arctic Ocean |
title_full |
Limited freshwater cap in the Eocene Arctic Ocean |
title_fullStr |
Limited freshwater cap in the Eocene Arctic Ocean |
title_full_unstemmed |
Limited freshwater cap in the Eocene Arctic Ocean |
title_sort |
limited freshwater cap in the eocene arctic ocean |
publisher |
Nature Publishing Group UK |
publishDate |
2019 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6414537/ http://www.ncbi.nlm.nih.gov/pubmed/30862936 https://doi.org/10.1038/s41598-019-40591-w |
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Arctic Arctic Ocean |
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Arctic Arctic Ocean |
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Arctic Arctic Ocean Lomonosov Ridge |
genre_facet |
Arctic Arctic Ocean Lomonosov Ridge |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6414537/ http://www.ncbi.nlm.nih.gov/pubmed/30862936 http://dx.doi.org/10.1038/s41598-019-40591-w |
op_rights |
© The Author(s) 2019 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
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CC-BY |
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https://doi.org/10.1038/s41598-019-40591-w |
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Scientific Reports |
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