Quantitative reconstruction of sea-surface conditions over the last 150 yr in the Beaufort Sea based on dinoflagellate cyst assemblages: the role of large-scale atmospheric circulation patterns
Dinoflagellate cyst (dinocyst) assemblages have been widely used over the Arctic Ocean to reconstruct sea-surface parameters on a quantitative basis. Such reconstructions provide insights into the role of anthropogenic vs natural forcings in the actual climatic trend. Here, we present the palynologi...
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Online Access: | https://doi.org/10.5194/bg-9-5391-2012 https://www.biogeosciences.net/9/5391/2012/ |
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ftcopernicus:oai:publications.copernicus.org:bg15124 2023-05-15T14:56:43+02:00 Quantitative reconstruction of sea-surface conditions over the last 150 yr in the Beaufort Sea based on dinoflagellate cyst assemblages: the role of large-scale atmospheric circulation patterns Durantou, L. Rochon, A. Ledu, D. Massé, G. Schmidt, S. Babin, M. 2018-09-27 info:eu-repo/semantics/application/pdf https://doi.org/10.5194/bg-9-5391-2012 https://www.biogeosciences.net/9/5391/2012/ eng eng info:eu-repo/grantAgreement/EC/FP7/203441 doi:10.5194/bg-9-5391-2012 https://www.biogeosciences.net/9/5391/2012/ info:eu-repo/semantics/openAccess eISSN: 1726-4189 info:eu-repo/semantics/Text 2018 ftcopernicus https://doi.org/10.5194/bg-9-5391-2012 2019-12-24T09:55:39Z Dinoflagellate cyst (dinocyst) assemblages have been widely used over the Arctic Ocean to reconstruct sea-surface parameters on a quantitative basis. Such reconstructions provide insights into the role of anthropogenic vs natural forcings in the actual climatic trend. Here, we present the palynological analysis of a dated 36 cm-long core collected from the Mackenzie Trough in the Canadian Beaufort Sea. Dinocyst assemblages were used to quantitatively reconstruct the evolution of sea-surface conditions (temperature, salinity, sea ice) and freshwater palynomorphs fluxes were used as local paleo-river discharge indicators over the last ~ 150 yr. Dinocyst assemblages are dominated by autotrophic taxa (68 to 96%). Cyst of Pentapharsodinium dalei is the dominant species throughout most of the core, except at the top where the assemblages are dominated by Operculodinium centrocarpum . Quantitative reconstructions of sea-surface parameters display a series of relatively warm, lower sea ice and saline episodes in surface waters, alternately with relatively cool and low salinity episodes. Variations of dinocyst fluxes and reconstructed sea-surface conditions may be closely linked to large scale atmospheric circulation patterns such as the Pacific Decadal Oscillation (PDO) and to a lesser degree, the Arctic Oscillation (AO). Positive phases of the PDO correspond to increases of dinocyst fluxes, warmer and saltier surface waters, which we associate with upwelling events of warm and relatively saline water from Pacific origin. Freshwater palynomorph fluxes increased in three phases from AD 1857 until reaching maximum values in AD 1991, suggesting that the Mackenzie River discharge followed the same trend when its discharge peaked between AD 1989 and AD 1992. The PDO mode seems to dominate the climatic variations at multi-annual to decadal timescales in the western Canadian Arctic and Beaufort Sea areas. Other/Unknown Material Arctic Arctic Ocean Beaufort Sea Mackenzie river Sea ice Copernicus Publications: E-Journals Arctic Arctic Ocean Mackenzie River MacKenzie Trough ENVELOPE(-138.025,-138.025,69.528,69.528) Pacific Biogeosciences 9 12 5391 5406 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Dinoflagellate cyst (dinocyst) assemblages have been widely used over the Arctic Ocean to reconstruct sea-surface parameters on a quantitative basis. Such reconstructions provide insights into the role of anthropogenic vs natural forcings in the actual climatic trend. Here, we present the palynological analysis of a dated 36 cm-long core collected from the Mackenzie Trough in the Canadian Beaufort Sea. Dinocyst assemblages were used to quantitatively reconstruct the evolution of sea-surface conditions (temperature, salinity, sea ice) and freshwater palynomorphs fluxes were used as local paleo-river discharge indicators over the last ~ 150 yr. Dinocyst assemblages are dominated by autotrophic taxa (68 to 96%). Cyst of Pentapharsodinium dalei is the dominant species throughout most of the core, except at the top where the assemblages are dominated by Operculodinium centrocarpum . Quantitative reconstructions of sea-surface parameters display a series of relatively warm, lower sea ice and saline episodes in surface waters, alternately with relatively cool and low salinity episodes. Variations of dinocyst fluxes and reconstructed sea-surface conditions may be closely linked to large scale atmospheric circulation patterns such as the Pacific Decadal Oscillation (PDO) and to a lesser degree, the Arctic Oscillation (AO). Positive phases of the PDO correspond to increases of dinocyst fluxes, warmer and saltier surface waters, which we associate with upwelling events of warm and relatively saline water from Pacific origin. Freshwater palynomorph fluxes increased in three phases from AD 1857 until reaching maximum values in AD 1991, suggesting that the Mackenzie River discharge followed the same trend when its discharge peaked between AD 1989 and AD 1992. The PDO mode seems to dominate the climatic variations at multi-annual to decadal timescales in the western Canadian Arctic and Beaufort Sea areas. |
format |
Other/Unknown Material |
author |
Durantou, L. Rochon, A. Ledu, D. Massé, G. Schmidt, S. Babin, M. |
spellingShingle |
Durantou, L. Rochon, A. Ledu, D. Massé, G. Schmidt, S. Babin, M. Quantitative reconstruction of sea-surface conditions over the last 150 yr in the Beaufort Sea based on dinoflagellate cyst assemblages: the role of large-scale atmospheric circulation patterns |
author_facet |
Durantou, L. Rochon, A. Ledu, D. Massé, G. Schmidt, S. Babin, M. |
author_sort |
Durantou, L. |
title |
Quantitative reconstruction of sea-surface conditions over the last 150 yr in the Beaufort Sea based on dinoflagellate cyst assemblages: the role of large-scale atmospheric circulation patterns |
title_short |
Quantitative reconstruction of sea-surface conditions over the last 150 yr in the Beaufort Sea based on dinoflagellate cyst assemblages: the role of large-scale atmospheric circulation patterns |
title_full |
Quantitative reconstruction of sea-surface conditions over the last 150 yr in the Beaufort Sea based on dinoflagellate cyst assemblages: the role of large-scale atmospheric circulation patterns |
title_fullStr |
Quantitative reconstruction of sea-surface conditions over the last 150 yr in the Beaufort Sea based on dinoflagellate cyst assemblages: the role of large-scale atmospheric circulation patterns |
title_full_unstemmed |
Quantitative reconstruction of sea-surface conditions over the last 150 yr in the Beaufort Sea based on dinoflagellate cyst assemblages: the role of large-scale atmospheric circulation patterns |
title_sort |
quantitative reconstruction of sea-surface conditions over the last 150 yr in the beaufort sea based on dinoflagellate cyst assemblages: the role of large-scale atmospheric circulation patterns |
publishDate |
2018 |
url |
https://doi.org/10.5194/bg-9-5391-2012 https://www.biogeosciences.net/9/5391/2012/ |
long_lat |
ENVELOPE(-138.025,-138.025,69.528,69.528) |
geographic |
Arctic Arctic Ocean Mackenzie River MacKenzie Trough Pacific |
geographic_facet |
Arctic Arctic Ocean Mackenzie River MacKenzie Trough Pacific |
genre |
Arctic Arctic Ocean Beaufort Sea Mackenzie river Sea ice |
genre_facet |
Arctic Arctic Ocean Beaufort Sea Mackenzie river Sea ice |
op_source |
eISSN: 1726-4189 |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/203441 doi:10.5194/bg-9-5391-2012 https://www.biogeosciences.net/9/5391/2012/ |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/bg-9-5391-2012 |
container_title |
Biogeosciences |
container_volume |
9 |
container_issue |
12 |
container_start_page |
5391 |
op_container_end_page |
5406 |
_version_ |
1766328796385902592 |