South Georgia marine productivity over the past 15 ka and implications for glacial evolution
The subantarctic islands of South Georgia are located in the Southern Ocean, and they may be sensitive to future climate warming. However, due to a lack of well-dated subantarctic palaeoclimate archives, there is still uncertainty about South Georgia's response to past climate change. Here, we...
Published in: | Journal of Micropalaeontology |
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European Geosciences Union
2024
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Online Access: | http://nora.nerc.ac.uk/id/eprint/536745/ https://nora.nerc.ac.uk/id/eprint/536745/1/jm-43-165-2024.pdf https://jm.copernicus.org/articles/43/165/2024/ |
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ftnerc:oai:nora.nerc.ac.uk:536745 2024-09-15T18:37:24+00:00 South Georgia marine productivity over the past 15 ka and implications for glacial evolution Wilkin, Jack T.R. Kender, Sev Dejardin, Rowan Allen, Claire S. Peck, Victoria L. Swann, George E.A. McClymont, Erin L. Scourse, James D. Littler, Kate Leng, Melanie J. 2024-06-18 text http://nora.nerc.ac.uk/id/eprint/536745/ https://nora.nerc.ac.uk/id/eprint/536745/1/jm-43-165-2024.pdf https://jm.copernicus.org/articles/43/165/2024/ en eng European Geosciences Union https://nora.nerc.ac.uk/id/eprint/536745/1/jm-43-165-2024.pdf Wilkin, Jack T.R.; Kender, Sev; Dejardin, Rowan; Allen, Claire S. orcid:0000-0002-0938-0551 Peck, Victoria L. orcid:0000-0002-7948-6853 Swann, George E.A.; McClymont, Erin L.; Scourse, James D.; Littler, Kate; Leng, Melanie J. orcid:0000-0003-1115-5166 . 2024 South Georgia marine productivity over the past 15 ka and implications for glacial evolution. Journal of Micropalaeontology, 43 (1). 165-186. https://doi.org/10.5194/jm-43-165-2024 <https://doi.org/10.5194/jm-43-165-2024> cc_by_4 Publication - Article PeerReviewed 2024 ftnerc https://doi.org/10.5194/jm-43-165-2024 2024-08-20T23:40:28Z The subantarctic islands of South Georgia are located in the Southern Ocean, and they may be sensitive to future climate warming. However, due to a lack of well-dated subantarctic palaeoclimate archives, there is still uncertainty about South Georgia's response to past climate change. Here, we reconstruct primary productivity changes and infer Holocene glacial evolution by analysing two marine gravity cores: one near Cumberland Bay on the inner South Georgia shelf (GC673: ca. 9.5 to 0.3 cal. kyr BP) and one offshore of Royal Bay on the mid-shelf (GC666: ca. 15.2 cal. kyr BP to present). We identify three distinct benthic foraminiferal assemblages characterised by the dominance of Miliammina earlandi, Fursenkoina fusiformis, and Cassidulinoides parkerianus that are considered alongside foraminiferal stable isotopes and the organic carbon and biogenic silica accumulation rates of the host sediment. The M. earlandi assemblage is prevalent during intervals of dissolution in GC666 and reduced productivity in GC673. The F. fusiformis assemblage coincides with enhanced productivity in both cores. Our multiproxy analysis provides evidence that the latest Pleistocene to earliest Holocene (ca. 15.2 to 10.5 cal. kyr BP) was a period of high productivity associated with increased glacial meltwater discharge. The mid–late Holocene (ca. 8 to 1 cal. kyr BP), coinciding with a fall in sedimentation rates and lower productivity, was likely a period of reduced glacial extent but with several short-lived episodes of increased productivity from minor glacial readvances. The latest Holocene (from ca. 1 cal. kyr BP) saw an increase in productivity and glacial advance associated with cooling temperatures and increased precipitation which may have been influenced by changes in the southwesterly winds over South Georgia. We interpret the elevated relative abundance of F. fusiformis as a proxy for increased primary productivity which, at proximal site GC673, was forced by terrestrial runoff associated with the spring–summer melting of ... Article in Journal/Newspaper Southern Ocean Natural Environment Research Council: NERC Open Research Archive Journal of Micropalaeontology 43 1 165 186 |
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Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
The subantarctic islands of South Georgia are located in the Southern Ocean, and they may be sensitive to future climate warming. However, due to a lack of well-dated subantarctic palaeoclimate archives, there is still uncertainty about South Georgia's response to past climate change. Here, we reconstruct primary productivity changes and infer Holocene glacial evolution by analysing two marine gravity cores: one near Cumberland Bay on the inner South Georgia shelf (GC673: ca. 9.5 to 0.3 cal. kyr BP) and one offshore of Royal Bay on the mid-shelf (GC666: ca. 15.2 cal. kyr BP to present). We identify three distinct benthic foraminiferal assemblages characterised by the dominance of Miliammina earlandi, Fursenkoina fusiformis, and Cassidulinoides parkerianus that are considered alongside foraminiferal stable isotopes and the organic carbon and biogenic silica accumulation rates of the host sediment. The M. earlandi assemblage is prevalent during intervals of dissolution in GC666 and reduced productivity in GC673. The F. fusiformis assemblage coincides with enhanced productivity in both cores. Our multiproxy analysis provides evidence that the latest Pleistocene to earliest Holocene (ca. 15.2 to 10.5 cal. kyr BP) was a period of high productivity associated with increased glacial meltwater discharge. The mid–late Holocene (ca. 8 to 1 cal. kyr BP), coinciding with a fall in sedimentation rates and lower productivity, was likely a period of reduced glacial extent but with several short-lived episodes of increased productivity from minor glacial readvances. The latest Holocene (from ca. 1 cal. kyr BP) saw an increase in productivity and glacial advance associated with cooling temperatures and increased precipitation which may have been influenced by changes in the southwesterly winds over South Georgia. We interpret the elevated relative abundance of F. fusiformis as a proxy for increased primary productivity which, at proximal site GC673, was forced by terrestrial runoff associated with the spring–summer melting of ... |
format |
Article in Journal/Newspaper |
author |
Wilkin, Jack T.R. Kender, Sev Dejardin, Rowan Allen, Claire S. Peck, Victoria L. Swann, George E.A. McClymont, Erin L. Scourse, James D. Littler, Kate Leng, Melanie J. |
spellingShingle |
Wilkin, Jack T.R. Kender, Sev Dejardin, Rowan Allen, Claire S. Peck, Victoria L. Swann, George E.A. McClymont, Erin L. Scourse, James D. Littler, Kate Leng, Melanie J. South Georgia marine productivity over the past 15 ka and implications for glacial evolution |
author_facet |
Wilkin, Jack T.R. Kender, Sev Dejardin, Rowan Allen, Claire S. Peck, Victoria L. Swann, George E.A. McClymont, Erin L. Scourse, James D. Littler, Kate Leng, Melanie J. |
author_sort |
Wilkin, Jack T.R. |
title |
South Georgia marine productivity over the past 15 ka and implications for glacial evolution |
title_short |
South Georgia marine productivity over the past 15 ka and implications for glacial evolution |
title_full |
South Georgia marine productivity over the past 15 ka and implications for glacial evolution |
title_fullStr |
South Georgia marine productivity over the past 15 ka and implications for glacial evolution |
title_full_unstemmed |
South Georgia marine productivity over the past 15 ka and implications for glacial evolution |
title_sort |
south georgia marine productivity over the past 15 ka and implications for glacial evolution |
publisher |
European Geosciences Union |
publishDate |
2024 |
url |
http://nora.nerc.ac.uk/id/eprint/536745/ https://nora.nerc.ac.uk/id/eprint/536745/1/jm-43-165-2024.pdf https://jm.copernicus.org/articles/43/165/2024/ |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
https://nora.nerc.ac.uk/id/eprint/536745/1/jm-43-165-2024.pdf Wilkin, Jack T.R.; Kender, Sev; Dejardin, Rowan; Allen, Claire S. orcid:0000-0002-0938-0551 Peck, Victoria L. orcid:0000-0002-7948-6853 Swann, George E.A.; McClymont, Erin L.; Scourse, James D.; Littler, Kate; Leng, Melanie J. orcid:0000-0003-1115-5166 . 2024 South Georgia marine productivity over the past 15 ka and implications for glacial evolution. Journal of Micropalaeontology, 43 (1). 165-186. https://doi.org/10.5194/jm-43-165-2024 <https://doi.org/10.5194/jm-43-165-2024> |
op_rights |
cc_by_4 |
op_doi |
https://doi.org/10.5194/jm-43-165-2024 |
container_title |
Journal of Micropalaeontology |
container_volume |
43 |
container_issue |
1 |
container_start_page |
165 |
op_container_end_page |
186 |
_version_ |
1810481762041593856 |