Sea ice and productivity changes over the last glacial cycle in the Adélie Land region, East Antarctica, based on diatom assemblage variability
Although diatoms can provide important palaeoenvironmental information about seasonal sea ice extent productivity, sea surface temperature, and ocean circulation variability, there are still relatively few studies analysing the last glacial cycle near the Antarctic continent. This study examines dia...
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ftcopernicus:oai:publications.copernicus.org:egusphere106775 2023-05-15T13:38:41+02:00 Sea ice and productivity changes over the last glacial cycle in the Adélie Land region, East Antarctica, based on diatom assemblage variability Pesjak, Lea McMinn, Andrew Chase, Zanna Bostock, Helen 2023-02-14 application/pdf https://doi.org/10.5194/egusphere-2022-1009 https://egusphere.copernicus.org/preprints/2022/egusphere-2022-1009/ eng eng doi:10.5194/egusphere-2022-1009 https://egusphere.copernicus.org/preprints/2022/egusphere-2022-1009/ eISSN: Text 2023 ftcopernicus https://doi.org/10.5194/egusphere-2022-1009 2023-02-20T17:22:55Z Although diatoms can provide important palaeoenvironmental information about seasonal sea ice extent productivity, sea surface temperature, and ocean circulation variability, there are still relatively few studies analysing the last glacial cycle near the Antarctic continent. This study examines diatom assemblages over the last glacial cycle from core TAN1302-44, offshore Adélie Land, East Antarctica. Two distinct diatom assemblages were identified using principal component analysis (PC 1–PC 2). The PC 1 assemblage is characterised by Thalassiosira lentiginosa , Actinocyclus actinochilus , Eucampia antarctica , Azpeitia tabularis and Asteromphalus hyalinus and is associated with the interglacial, sedimentary Facies 1, suggesting that the MIS 5e and Holocene interglacials were characterised by seasonal sea ice environments with similar ocean temperature and circulation. The PC 2 assemblage is characterised by Fragilariopsis obliquecostata , Asteromphalus parvulus and Thalassiosira tumida and is associated with the glacial Facies 2. The variability of PC 2 indicates that, during the MIS 4–2 glacial and the last glaciation, there was an increase in the length of the sea ice season compared with that of the interglacial period, yet there was still no permanent sea ice cover. The initial increase of PC 2 at the start of the glaciation stage and then the gradual increase throughout late MIS 4–2 suggest that sea ice cover steadily increased, reaching a maximum towards the end of MIS 2. The increase in sea ice during glaciation and MIS 4–2 glacial is further supported by the increase in the Eucampia index (terminal/intercalary valve ratio), an additional proxy for sea ice, which coincides with increases in PC 2. Aside from the statistical results, the increase in the relative abundance of Thalassiothrix antarctica at 40 and 270 cm suggests that, during the last two deglacials, there was a period of enhanced nutrient delivery, which is inferred to reflect an increase in upwelling of Circumpolar Deep Water. Interestingly, ... Text Antarc* Antarctic Antarctica East Antarctica Sea ice Copernicus Publications: E-Journals Antarctic East Antarctica The Antarctic |
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Copernicus Publications: E-Journals |
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English |
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Although diatoms can provide important palaeoenvironmental information about seasonal sea ice extent productivity, sea surface temperature, and ocean circulation variability, there are still relatively few studies analysing the last glacial cycle near the Antarctic continent. This study examines diatom assemblages over the last glacial cycle from core TAN1302-44, offshore Adélie Land, East Antarctica. Two distinct diatom assemblages were identified using principal component analysis (PC 1–PC 2). The PC 1 assemblage is characterised by Thalassiosira lentiginosa , Actinocyclus actinochilus , Eucampia antarctica , Azpeitia tabularis and Asteromphalus hyalinus and is associated with the interglacial, sedimentary Facies 1, suggesting that the MIS 5e and Holocene interglacials were characterised by seasonal sea ice environments with similar ocean temperature and circulation. The PC 2 assemblage is characterised by Fragilariopsis obliquecostata , Asteromphalus parvulus and Thalassiosira tumida and is associated with the glacial Facies 2. The variability of PC 2 indicates that, during the MIS 4–2 glacial and the last glaciation, there was an increase in the length of the sea ice season compared with that of the interglacial period, yet there was still no permanent sea ice cover. The initial increase of PC 2 at the start of the glaciation stage and then the gradual increase throughout late MIS 4–2 suggest that sea ice cover steadily increased, reaching a maximum towards the end of MIS 2. The increase in sea ice during glaciation and MIS 4–2 glacial is further supported by the increase in the Eucampia index (terminal/intercalary valve ratio), an additional proxy for sea ice, which coincides with increases in PC 2. Aside from the statistical results, the increase in the relative abundance of Thalassiothrix antarctica at 40 and 270 cm suggests that, during the last two deglacials, there was a period of enhanced nutrient delivery, which is inferred to reflect an increase in upwelling of Circumpolar Deep Water. Interestingly, ... |
format |
Text |
author |
Pesjak, Lea McMinn, Andrew Chase, Zanna Bostock, Helen |
spellingShingle |
Pesjak, Lea McMinn, Andrew Chase, Zanna Bostock, Helen Sea ice and productivity changes over the last glacial cycle in the Adélie Land region, East Antarctica, based on diatom assemblage variability |
author_facet |
Pesjak, Lea McMinn, Andrew Chase, Zanna Bostock, Helen |
author_sort |
Pesjak, Lea |
title |
Sea ice and productivity changes over the last glacial cycle in the Adélie Land region, East Antarctica, based on diatom assemblage variability |
title_short |
Sea ice and productivity changes over the last glacial cycle in the Adélie Land region, East Antarctica, based on diatom assemblage variability |
title_full |
Sea ice and productivity changes over the last glacial cycle in the Adélie Land region, East Antarctica, based on diatom assemblage variability |
title_fullStr |
Sea ice and productivity changes over the last glacial cycle in the Adélie Land region, East Antarctica, based on diatom assemblage variability |
title_full_unstemmed |
Sea ice and productivity changes over the last glacial cycle in the Adélie Land region, East Antarctica, based on diatom assemblage variability |
title_sort |
sea ice and productivity changes over the last glacial cycle in the adélie land region, east antarctica, based on diatom assemblage variability |
publishDate |
2023 |
url |
https://doi.org/10.5194/egusphere-2022-1009 https://egusphere.copernicus.org/preprints/2022/egusphere-2022-1009/ |
geographic |
Antarctic East Antarctica The Antarctic |
geographic_facet |
Antarctic East Antarctica The Antarctic |
genre |
Antarc* Antarctic Antarctica East Antarctica Sea ice |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Sea ice |
op_source |
eISSN: |
op_relation |
doi:10.5194/egusphere-2022-1009 https://egusphere.copernicus.org/preprints/2022/egusphere-2022-1009/ |
op_doi |
https://doi.org/10.5194/egusphere-2022-1009 |
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1766109873041309696 |