Sea ice variability in the Nordic Seas over Dansgaard–Oeschger climate cycles during the last glacial – A biomarker approach
The Arctic sea ice cover is in fast transition. Resolving past sea ice fluctuations and its link with abrupt climate change might be key for a better understanding of yet unknown climatic consequences of future Arctic sea ice loss. The last glacial period was marked by recurring abrupt climate chang...
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University of Bergen
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fttriple:oai:gotriple.eu:10670/1.wlsucd 2023-05-15T14:58:00+02:00 Sea ice variability in the Nordic Seas over Dansgaard–Oeschger climate cycles during the last glacial – A biomarker approach Sadatzki, Henrik 2019-01-01 https://archimer.ifremer.fr/doc/00505/61699/65667.pdf https://archimer.ifremer.fr/doc/00505/61699/ en eng University of Bergen 10670/1.wlsucd https://archimer.ifremer.fr/doc/00505/61699/65667.pdf https://archimer.ifremer.fr/doc/00505/61699/ other Archimer, archive institutionnelle de l'Ifremer envir geo Text https://vocabularies.coar-repositories.org/resource_types/c_18cf/ 2019 fttriple 2023-01-22T16:56:34Z The Arctic sea ice cover is in fast transition. Resolving past sea ice fluctuations and its link with abrupt climate change might be key for a better understanding of yet unknown climatic consequences of future Arctic sea ice loss. The last glacial period was marked by recurring abrupt climate changes, referred to as Dansgaard–Oeschger (D–O) climate cycles. These D–O climate cycles and in particular the associated abrupt warming transitions by up to 15°C over Greenland happening within years or decades might have been linked to shifts in sea ice cover in the Nordic Seas. This PhD thesis aims at resolving and constraining the largely unknown millennialscale sea ice variability in the Nordic Seas and its pivotal role for abrupt climate changes during the D–O cycles based on empirical proxy data evidence. Novel sea ice reconstructions are mainly based on the sedimentary abundances of the sea ice algae biomarker IP25 and open-water phytoplankton biomarkers. This thesis includes two multi-decadal to centennial-scale biomarker sea ice records from the southern and central Norwegian Sea covering the time period ~30–40 thousand years ago, which reveal unprecedented insights into the nature of glacial sea ice fluctuations during D–O cycles (Papers 1 and 2). A comparison of these biomarker sea ice records with LOVECLIM model output data of sea ice cover (Paper 1) and a new bromine-enrichment sea ice record from the RECAP ice core (East Greenland) (Paper 2), sheds light on the mechanisms and timing of rapid sea ice shifts with respect to abrupt Greenland climate changes. A third biomarker sea ice record from the Eirik Drift south of Greenland elucidates the sea ice cover and export in the northwestern North Atlantic ~30–40 thousand years ago (Paper 3). This thesis also comprises a calibration based on a robust linear correlation between the sea ice index PIP25 in (sub-)Arctic surface sediments and modern spring sea ice concentration, which allows a quantification of past sea ice changes (Paper 2). The results presented in ... Text Arctic Climate change East Greenland Greenland ice algae ice core Nordic Seas North Atlantic Norwegian Sea Phytoplankton Sea ice Unknown Arctic Greenland Norwegian Sea |
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envir geo Sadatzki, Henrik Sea ice variability in the Nordic Seas over Dansgaard–Oeschger climate cycles during the last glacial – A biomarker approach |
topic_facet |
envir geo |
description |
The Arctic sea ice cover is in fast transition. Resolving past sea ice fluctuations and its link with abrupt climate change might be key for a better understanding of yet unknown climatic consequences of future Arctic sea ice loss. The last glacial period was marked by recurring abrupt climate changes, referred to as Dansgaard–Oeschger (D–O) climate cycles. These D–O climate cycles and in particular the associated abrupt warming transitions by up to 15°C over Greenland happening within years or decades might have been linked to shifts in sea ice cover in the Nordic Seas. This PhD thesis aims at resolving and constraining the largely unknown millennialscale sea ice variability in the Nordic Seas and its pivotal role for abrupt climate changes during the D–O cycles based on empirical proxy data evidence. Novel sea ice reconstructions are mainly based on the sedimentary abundances of the sea ice algae biomarker IP25 and open-water phytoplankton biomarkers. This thesis includes two multi-decadal to centennial-scale biomarker sea ice records from the southern and central Norwegian Sea covering the time period ~30–40 thousand years ago, which reveal unprecedented insights into the nature of glacial sea ice fluctuations during D–O cycles (Papers 1 and 2). A comparison of these biomarker sea ice records with LOVECLIM model output data of sea ice cover (Paper 1) and a new bromine-enrichment sea ice record from the RECAP ice core (East Greenland) (Paper 2), sheds light on the mechanisms and timing of rapid sea ice shifts with respect to abrupt Greenland climate changes. A third biomarker sea ice record from the Eirik Drift south of Greenland elucidates the sea ice cover and export in the northwestern North Atlantic ~30–40 thousand years ago (Paper 3). This thesis also comprises a calibration based on a robust linear correlation between the sea ice index PIP25 in (sub-)Arctic surface sediments and modern spring sea ice concentration, which allows a quantification of past sea ice changes (Paper 2). The results presented in ... |
format |
Text |
author |
Sadatzki, Henrik |
author_facet |
Sadatzki, Henrik |
author_sort |
Sadatzki, Henrik |
title |
Sea ice variability in the Nordic Seas over Dansgaard–Oeschger climate cycles during the last glacial – A biomarker approach |
title_short |
Sea ice variability in the Nordic Seas over Dansgaard–Oeschger climate cycles during the last glacial – A biomarker approach |
title_full |
Sea ice variability in the Nordic Seas over Dansgaard–Oeschger climate cycles during the last glacial – A biomarker approach |
title_fullStr |
Sea ice variability in the Nordic Seas over Dansgaard–Oeschger climate cycles during the last glacial – A biomarker approach |
title_full_unstemmed |
Sea ice variability in the Nordic Seas over Dansgaard–Oeschger climate cycles during the last glacial – A biomarker approach |
title_sort |
sea ice variability in the nordic seas over dansgaard–oeschger climate cycles during the last glacial – a biomarker approach |
publisher |
University of Bergen |
publishDate |
2019 |
url |
https://archimer.ifremer.fr/doc/00505/61699/65667.pdf https://archimer.ifremer.fr/doc/00505/61699/ |
geographic |
Arctic Greenland Norwegian Sea |
geographic_facet |
Arctic Greenland Norwegian Sea |
genre |
Arctic Climate change East Greenland Greenland ice algae ice core Nordic Seas North Atlantic Norwegian Sea Phytoplankton Sea ice |
genre_facet |
Arctic Climate change East Greenland Greenland ice algae ice core Nordic Seas North Atlantic Norwegian Sea Phytoplankton Sea ice |
op_source |
Archimer, archive institutionnelle de l'Ifremer |
op_relation |
10670/1.wlsucd https://archimer.ifremer.fr/doc/00505/61699/65667.pdf https://archimer.ifremer.fr/doc/00505/61699/ |
op_rights |
other |
_version_ |
1766330099070664704 |