Productivité et flux de carbone dans la mer du Labrador au cours des derniers 40 000 ans
Geochemical and micropaleontological analyses of Labrador Sea sediments allowed us to intercalibrate indicators of paleoproductivity and paleofluxes of carbon and to reconstitute biogeochemical fluxes, notably in relation to deep sea circulation changes (Western Boundary Undercurrent and North Atlan...
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Online Access: | http://dx.doi.org/10.1139/e94-012 http://www.nrcresearchpress.com/doi/pdf/10.1139/e94-012 |
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crcansciencepubl:10.1139/e94-012 2023-12-17T10:31:51+01:00 Productivité et flux de carbone dans la mer du Labrador au cours des derniers 40 000 ans Hillaire-Marcel, Claude Vernal, Anne de Lucotte, Marc Mucci, Alfonso Bilodeau, Guy Rochon, André Vallières, Sylvain Wu, Guoping 1994 http://dx.doi.org/10.1139/e94-012 http://www.nrcresearchpress.com/doi/pdf/10.1139/e94-012 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 31, issue 1, page 139-158 ISSN 0008-4077 1480-3313 General Earth and Planetary Sciences journal-article 1994 crcansciencepubl https://doi.org/10.1139/e94-012 2023-11-19T13:38:41Z Geochemical and micropaleontological analyses of Labrador Sea sediments allowed us to intercalibrate indicators of paleoproductivity and paleofluxes of carbon and to reconstitute biogeochemical fluxes, notably in relation to deep sea circulation changes (Western Boundary Undercurrent and North Atlantic Deep Water). Linear or logarithmic relations are observed between the subrecent fluxes of paleoproductivity indicators (coccoliths, diatoms, dinocysts, 230 Th), the 13 C content of left-coiling or sinistral Neogloboquadrina pachyderma, the modern surface water carbon production, and the rates of organic and inorganic carbon (C org , C inorg ) burial. All indicators increase by a factor of 10 2 to 10 3 in response to the evolution of paleosea-surface conditions since the last glacial maximum. Correlations are observed between authigenic C inorg , 230 Th, coccoliths, and 13 C content (left-coiling or sinistral Neogloboquadrina pachyderma), and also between authigenic C org , dinocysts, uranium, and sulfur. Relative C inorg /C org burial rates in the deep sediments (> 3000 m) allow us to calculate a net CO 2 production in the basin. The net CO 2 flux was slightly negative between ~ 20 and ~ 15 ka BP. It reached a first maximum at about 9 ka BP (~ 30 μmol∙cm −2 ∙a −1 CO 2 ) followed by a decrease at ~ 8 ka BP (~ 20 μmol∙cm −2 ∙a −1 ). Since about 7 ka BP, it stabilized at ~ 35 μmol∙cm −2 ∙a −1 . The minimum observed at about 8 ka BP corresponds to a significant rate of C org burial accompanied with a maximum flux of redox-sensitive indicators (uranium, sulfur). This event does not correspond to any change in sea-surface temperature or salinity, nor in deep circulation, but may be related to the reorganization of the atmospheric circulation during a major breakup stage of the Laurentide ice sheet. The close correlation between the change in CO 2 production in the Labrador Sea with variations of atmospheric CO 2 concentrations during the last 20 ka BP suggests that the production of biogenic carbonates in ... Article in Journal/Newspaper Ice Sheet Labrador Sea Neogloboquadrina pachyderma North Atlantic Deep Water North Atlantic Canadian Science Publishing (via Crossref) Mer du Labrador ENVELOPE(-55.998,-55.998,55.000,55.000) Canadian Journal of Earth Sciences 31 1 139 158 |
institution |
Open Polar |
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Canadian Science Publishing (via Crossref) |
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crcansciencepubl |
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English |
topic |
General Earth and Planetary Sciences |
spellingShingle |
General Earth and Planetary Sciences Hillaire-Marcel, Claude Vernal, Anne de Lucotte, Marc Mucci, Alfonso Bilodeau, Guy Rochon, André Vallières, Sylvain Wu, Guoping Productivité et flux de carbone dans la mer du Labrador au cours des derniers 40 000 ans |
topic_facet |
General Earth and Planetary Sciences |
description |
Geochemical and micropaleontological analyses of Labrador Sea sediments allowed us to intercalibrate indicators of paleoproductivity and paleofluxes of carbon and to reconstitute biogeochemical fluxes, notably in relation to deep sea circulation changes (Western Boundary Undercurrent and North Atlantic Deep Water). Linear or logarithmic relations are observed between the subrecent fluxes of paleoproductivity indicators (coccoliths, diatoms, dinocysts, 230 Th), the 13 C content of left-coiling or sinistral Neogloboquadrina pachyderma, the modern surface water carbon production, and the rates of organic and inorganic carbon (C org , C inorg ) burial. All indicators increase by a factor of 10 2 to 10 3 in response to the evolution of paleosea-surface conditions since the last glacial maximum. Correlations are observed between authigenic C inorg , 230 Th, coccoliths, and 13 C content (left-coiling or sinistral Neogloboquadrina pachyderma), and also between authigenic C org , dinocysts, uranium, and sulfur. Relative C inorg /C org burial rates in the deep sediments (> 3000 m) allow us to calculate a net CO 2 production in the basin. The net CO 2 flux was slightly negative between ~ 20 and ~ 15 ka BP. It reached a first maximum at about 9 ka BP (~ 30 μmol∙cm −2 ∙a −1 CO 2 ) followed by a decrease at ~ 8 ka BP (~ 20 μmol∙cm −2 ∙a −1 ). Since about 7 ka BP, it stabilized at ~ 35 μmol∙cm −2 ∙a −1 . The minimum observed at about 8 ka BP corresponds to a significant rate of C org burial accompanied with a maximum flux of redox-sensitive indicators (uranium, sulfur). This event does not correspond to any change in sea-surface temperature or salinity, nor in deep circulation, but may be related to the reorganization of the atmospheric circulation during a major breakup stage of the Laurentide ice sheet. The close correlation between the change in CO 2 production in the Labrador Sea with variations of atmospheric CO 2 concentrations during the last 20 ka BP suggests that the production of biogenic carbonates in ... |
format |
Article in Journal/Newspaper |
author |
Hillaire-Marcel, Claude Vernal, Anne de Lucotte, Marc Mucci, Alfonso Bilodeau, Guy Rochon, André Vallières, Sylvain Wu, Guoping |
author_facet |
Hillaire-Marcel, Claude Vernal, Anne de Lucotte, Marc Mucci, Alfonso Bilodeau, Guy Rochon, André Vallières, Sylvain Wu, Guoping |
author_sort |
Hillaire-Marcel, Claude |
title |
Productivité et flux de carbone dans la mer du Labrador au cours des derniers 40 000 ans |
title_short |
Productivité et flux de carbone dans la mer du Labrador au cours des derniers 40 000 ans |
title_full |
Productivité et flux de carbone dans la mer du Labrador au cours des derniers 40 000 ans |
title_fullStr |
Productivité et flux de carbone dans la mer du Labrador au cours des derniers 40 000 ans |
title_full_unstemmed |
Productivité et flux de carbone dans la mer du Labrador au cours des derniers 40 000 ans |
title_sort |
productivité et flux de carbone dans la mer du labrador au cours des derniers 40 000 ans |
publisher |
Canadian Science Publishing |
publishDate |
1994 |
url |
http://dx.doi.org/10.1139/e94-012 http://www.nrcresearchpress.com/doi/pdf/10.1139/e94-012 |
long_lat |
ENVELOPE(-55.998,-55.998,55.000,55.000) |
geographic |
Mer du Labrador |
geographic_facet |
Mer du Labrador |
genre |
Ice Sheet Labrador Sea Neogloboquadrina pachyderma North Atlantic Deep Water North Atlantic |
genre_facet |
Ice Sheet Labrador Sea Neogloboquadrina pachyderma North Atlantic Deep Water North Atlantic |
op_source |
Canadian Journal of Earth Sciences volume 31, issue 1, page 139-158 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e94-012 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
31 |
container_issue |
1 |
container_start_page |
139 |
op_container_end_page |
158 |
_version_ |
1785585267521880064 |