Hydrography in the Nordic Seas During Dansgaard-Oeschger Events 8-5
The modern rapidity of Arctic sea ice loss and rise in Arctic air and ocean temperatures is pushing research to understand mechanisms for abrupt climate fluctuations. Resolving the mechanisms of past abrupt changes is a key tool for illuminating potential future reorganization of the climate system....
Published in: | Paleoceanography and Paleoclimatology |
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Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
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The University of Bergen
2019
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Online Access: | https://hdl.handle.net/1956/20878 |
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ftunivbergen:oai:bora.uib.no:1956/20878 2023-05-15T14:56:40+02:00 Hydrography in the Nordic Seas During Dansgaard-Oeschger Events 8-5 Sessford, Evangeline orcid:0000-0002-6533-6248 2019-06-14 application/pdf https://hdl.handle.net/1956/20878 eng eng The University of Bergen Paper I: Sessford, E.G., Tisserand, A.A., Risebrobakken, B., Andersson, C., Dokken, T., and Jansen, E. 2018: High resolution benthic Mg/Ca temperature record of the intermediate water in the Denmark Strait across DO stadial-interstadial cycles. Paleoceanography and Paleoclimatology, 33 (11), 1169-1185. The article is available in the main thesis. The article is also available at: https://doi.org/10.1029/2018PA003370 Paper II: Sessford, E.G., Jensen, M.F., Tisserand, A.A., Muschtiello, F., Dokken, T., Nisancioglu, K.H., Jansen, E. Coherent fluctuations in intermediate water temperature off the coast of Greenland and Norway during Dansgaard- Oeschger events. The article is not available in BORA. The article is available at: https://doi.org/10.1016/j.quascirev.2019.105887 Paper III: Sessford, E.G., Wille, S.B., Tisserand, A.A., Jansen, E. Surface and deep-water interactions in the Nordic Seas during Greenland Stadial 9 to Greenland Interstadial 8. The article is not available in BORA. Paper IV: Sessford, E.G., Tisserand, A.A. and Chalk, T.B. The relationship between carbonate ion saturation and Mg/Ca temperature reconstructions for the benthic species C. neoteretis. The article is not available in BORA. https://hdl.handle.net/1956/20878 cristin:1708957 In copyright http://rightsstatements.org/page/InC/1.0/ Copyright the author. All rights reserved. Doctoral thesis 2019 ftunivbergen https://doi.org/10.1029/2018PA00337010.1016/j.quascirev.2019.105887 2023-03-14T17:39:59Z The modern rapidity of Arctic sea ice loss and rise in Arctic air and ocean temperatures is pushing research to understand mechanisms for abrupt climate fluctuations. Resolving the mechanisms of past abrupt changes is a key tool for illuminating potential future reorganization of the climate system. A series of large and abrupt climate fluctuations, first discovered in Greenland ice cores and characterized by sudden warmings followed by more gradual coolings, referred to as Dansgaard- Oeschger events, punctuated the last glacial period. These fluctuations are thought to be linked to changes in the hydrography of the Nordic Seas. In order to draw parallels to the modern changes taking place in the Arctic, this thesis studies the reorganization of the hydrography in the Nordic Seas during Dansgaard-Oeschger events 8-5 (40-30 ka b2k). This thesis aims to resolve the role that the Nordic Seas hydrography played in the climate fluctuations of the Dansgaard-Oeschger events. To do this, geochemical analysis of foraminiferal CaCO3 and its trace and major elements, alongside oxygen and carbon isotopes of the same foraminiferal species are used to reconstruct a picture of the hydrographical conditions in the Nordic Seas. Two sediment cores are implemented; one from the Denmark Strait, and the other from the Faroe-Shetland Channel, to capture the inflow and outflow regions to the Nordic Seas. A combination of near surface and intermediate water proxies are used to reconstruct the water column in both these regions. The combined results of research Papers 1-3 highlight a Nordic Seas that reorganized itself as sea ice retreated and expanded in time with the Dansgaard-Oeschger cycles. Colder air temperatures and expanded sea ice cover are linked to a well-stratified cold and fresh surface underlain by a homogenized warm intermediate water of Atlantic origin across the entire Nordic Seas basin. When warm air temperatures and reduced sea ice cover are present, the eastern and western Nordic Seas are decoupled. Disintegration of ... Doctoral or Postdoctoral Thesis Arctic Dansgaard-Oeschger events Denmark Strait Foraminifera* Greenland Greenland ice cores Nordic Seas Sea ice University of Bergen: Bergen Open Research Archive (BORA-UiB) Arctic Greenland Paleoceanography and Paleoclimatology 33 11 1169 1185 |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
description |
The modern rapidity of Arctic sea ice loss and rise in Arctic air and ocean temperatures is pushing research to understand mechanisms for abrupt climate fluctuations. Resolving the mechanisms of past abrupt changes is a key tool for illuminating potential future reorganization of the climate system. A series of large and abrupt climate fluctuations, first discovered in Greenland ice cores and characterized by sudden warmings followed by more gradual coolings, referred to as Dansgaard- Oeschger events, punctuated the last glacial period. These fluctuations are thought to be linked to changes in the hydrography of the Nordic Seas. In order to draw parallels to the modern changes taking place in the Arctic, this thesis studies the reorganization of the hydrography in the Nordic Seas during Dansgaard-Oeschger events 8-5 (40-30 ka b2k). This thesis aims to resolve the role that the Nordic Seas hydrography played in the climate fluctuations of the Dansgaard-Oeschger events. To do this, geochemical analysis of foraminiferal CaCO3 and its trace and major elements, alongside oxygen and carbon isotopes of the same foraminiferal species are used to reconstruct a picture of the hydrographical conditions in the Nordic Seas. Two sediment cores are implemented; one from the Denmark Strait, and the other from the Faroe-Shetland Channel, to capture the inflow and outflow regions to the Nordic Seas. A combination of near surface and intermediate water proxies are used to reconstruct the water column in both these regions. The combined results of research Papers 1-3 highlight a Nordic Seas that reorganized itself as sea ice retreated and expanded in time with the Dansgaard-Oeschger cycles. Colder air temperatures and expanded sea ice cover are linked to a well-stratified cold and fresh surface underlain by a homogenized warm intermediate water of Atlantic origin across the entire Nordic Seas basin. When warm air temperatures and reduced sea ice cover are present, the eastern and western Nordic Seas are decoupled. Disintegration of ... |
author2 |
orcid:0000-0002-6533-6248 |
format |
Doctoral or Postdoctoral Thesis |
author |
Sessford, Evangeline |
spellingShingle |
Sessford, Evangeline Hydrography in the Nordic Seas During Dansgaard-Oeschger Events 8-5 |
author_facet |
Sessford, Evangeline |
author_sort |
Sessford, Evangeline |
title |
Hydrography in the Nordic Seas During Dansgaard-Oeschger Events 8-5 |
title_short |
Hydrography in the Nordic Seas During Dansgaard-Oeschger Events 8-5 |
title_full |
Hydrography in the Nordic Seas During Dansgaard-Oeschger Events 8-5 |
title_fullStr |
Hydrography in the Nordic Seas During Dansgaard-Oeschger Events 8-5 |
title_full_unstemmed |
Hydrography in the Nordic Seas During Dansgaard-Oeschger Events 8-5 |
title_sort |
hydrography in the nordic seas during dansgaard-oeschger events 8-5 |
publisher |
The University of Bergen |
publishDate |
2019 |
url |
https://hdl.handle.net/1956/20878 |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Arctic Dansgaard-Oeschger events Denmark Strait Foraminifera* Greenland Greenland ice cores Nordic Seas Sea ice |
genre_facet |
Arctic Dansgaard-Oeschger events Denmark Strait Foraminifera* Greenland Greenland ice cores Nordic Seas Sea ice |
op_relation |
Paper I: Sessford, E.G., Tisserand, A.A., Risebrobakken, B., Andersson, C., Dokken, T., and Jansen, E. 2018: High resolution benthic Mg/Ca temperature record of the intermediate water in the Denmark Strait across DO stadial-interstadial cycles. Paleoceanography and Paleoclimatology, 33 (11), 1169-1185. The article is available in the main thesis. The article is also available at: https://doi.org/10.1029/2018PA003370 Paper II: Sessford, E.G., Jensen, M.F., Tisserand, A.A., Muschtiello, F., Dokken, T., Nisancioglu, K.H., Jansen, E. Coherent fluctuations in intermediate water temperature off the coast of Greenland and Norway during Dansgaard- Oeschger events. The article is not available in BORA. The article is available at: https://doi.org/10.1016/j.quascirev.2019.105887 Paper III: Sessford, E.G., Wille, S.B., Tisserand, A.A., Jansen, E. Surface and deep-water interactions in the Nordic Seas during Greenland Stadial 9 to Greenland Interstadial 8. The article is not available in BORA. Paper IV: Sessford, E.G., Tisserand, A.A. and Chalk, T.B. The relationship between carbonate ion saturation and Mg/Ca temperature reconstructions for the benthic species C. neoteretis. The article is not available in BORA. https://hdl.handle.net/1956/20878 cristin:1708957 |
op_rights |
In copyright http://rightsstatements.org/page/InC/1.0/ Copyright the author. All rights reserved. |
op_doi |
https://doi.org/10.1029/2018PA00337010.1016/j.quascirev.2019.105887 |
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Paleoceanography and Paleoclimatology |
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33 |
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11 |
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