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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Copernicus Publications
2023
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ftdoajarticles:oai:doaj.org/article:37b7c3451a734e2bae0ee11aa5a6aa18 2023-05-15T13:36:36+02:00 Sea ice and productivity changes over the last glacial cycle in the Adélie Land region, East Antarctica, based on diatom assemblage variability L. Pesjak A. McMinn Z. Chase H. Bostock 2023-02-01T00:00:00Z https://doi.org/10.5194/cp-19-419-2023 https://doaj.org/article/37b7c3451a734e2bae0ee11aa5a6aa18 EN eng Copernicus Publications https://cp.copernicus.org/articles/19/419/2023/cp-19-419-2023.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-19-419-2023 1814-9324 1814-9332 https://doaj.org/article/37b7c3451a734e2bae0ee11aa5a6aa18 Climate of the Past, Vol 19, Pp 419-437 (2023) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2023 ftdoajarticles https://doi.org/10.5194/cp-19-419-2023 2023-02-19T01:46:54Z 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, ... Article in Journal/Newspaper Antarc* Antarctic Antarctica East Antarctica Sea ice Directory of Open Access Journals: DOAJ Articles Antarctic The Antarctic East Antarctica Climate of the Past 19 2 419 437 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
spellingShingle |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 L. Pesjak A. McMinn Z. Chase H. Bostock Sea ice and productivity changes over the last glacial cycle in the Adélie Land region, East Antarctica, based on diatom assemblage variability |
topic_facet |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
description |
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 |
Article in Journal/Newspaper |
author |
L. Pesjak A. McMinn Z. Chase H. Bostock |
author_facet |
L. Pesjak A. McMinn Z. Chase H. Bostock |
author_sort |
L. Pesjak |
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 |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/cp-19-419-2023 https://doaj.org/article/37b7c3451a734e2bae0ee11aa5a6aa18 |
geographic |
Antarctic The Antarctic East Antarctica |
geographic_facet |
Antarctic The Antarctic East Antarctica |
genre |
Antarc* Antarctic Antarctica East Antarctica Sea ice |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Sea ice |
op_source |
Climate of the Past, Vol 19, Pp 419-437 (2023) |
op_relation |
https://cp.copernicus.org/articles/19/419/2023/cp-19-419-2023.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-19-419-2023 1814-9324 1814-9332 https://doaj.org/article/37b7c3451a734e2bae0ee11aa5a6aa18 |
op_doi |
https://doi.org/10.5194/cp-19-419-2023 |
container_title |
Climate of the Past |
container_volume |
19 |
container_issue |
2 |
container_start_page |
419 |
op_container_end_page |
437 |
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1766081661952327680 |