Trace metal evidence for a poorly ventilated glacial Southern Ocean
Glacial benthic δ13C and Δ14C measurements from the Atlantic Ocean have been interpreted to indicate the existence of a poorly ventilated Southern Ocean with greater CO2 and nutrient contents compared to present. Enhanced storage of CO2 in the deep ocean predicts that oxygen concentrations should ha...
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fttriple:oai:gotriple.eu:10670/1.ekr214 2023-05-15T18:23:43+02:00 Trace metal evidence for a poorly ventilated glacial Southern Ocean Wagner, M. Hendy, I. L. 2018-09-26 https://doi.org/10.5194/cpd-11-637-2015 https://cp.copernicus.org/preprints/cp-2014-148/ en eng doi:10.5194/cpd-11-637-2015 10670/1.ekr214 https://cp.copernicus.org/preprints/cp-2014-148/ undefined Geographica Helvetica - geography eISSN: 1814-9332 envir geo Text https://vocabularies.coar-repositories.org/resource_types/c_18cf/ 2018 fttriple https://doi.org/10.5194/cpd-11-637-2015 2023-01-22T17:06:30Z Glacial benthic δ13C and Δ14C measurements from the Atlantic Ocean have been interpreted to indicate the existence of a poorly ventilated Southern Ocean with greater CO2 and nutrient contents compared to present. Enhanced storage of CO2 in the deep ocean predicts that oxygen concentrations should have declined at the same time, although no unequivocal evidence for glacial Southern Ocean suboxia has yet been found. Here we take a novel approach by using concentrations of redox-sensitive trace metals to show that Southern Ocean sediments from two cores in the Atlantic sector were suboxic during deglaciation and the last glacial period, implying reduced ventilation and/or elevated export production that significantly altered deep water chemistry. In the Cape Basin, high concentrations of the authigenically deposited trace metal Re coincide with oldest Δ14C values at 3.8 km water depth in the Subantarctic Zone, indicating that poorest Southern Ocean ventilation occurred during the Last Glacial Maximum (~ 23–19 ka). Furthermore, trace metal results suggest that the vertical structure of the glacial Southern Ocean differed from modern deep water mass arrangement such that Lower Circumpolar Deep Water had lower O2 concentrations, and therefore was the likely reservoir of glacial CO2. Text Southern Ocean Unknown Southern Ocean |
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envir geo Wagner, M. Hendy, I. L. Trace metal evidence for a poorly ventilated glacial Southern Ocean |
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envir geo |
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Glacial benthic δ13C and Δ14C measurements from the Atlantic Ocean have been interpreted to indicate the existence of a poorly ventilated Southern Ocean with greater CO2 and nutrient contents compared to present. Enhanced storage of CO2 in the deep ocean predicts that oxygen concentrations should have declined at the same time, although no unequivocal evidence for glacial Southern Ocean suboxia has yet been found. Here we take a novel approach by using concentrations of redox-sensitive trace metals to show that Southern Ocean sediments from two cores in the Atlantic sector were suboxic during deglaciation and the last glacial period, implying reduced ventilation and/or elevated export production that significantly altered deep water chemistry. In the Cape Basin, high concentrations of the authigenically deposited trace metal Re coincide with oldest Δ14C values at 3.8 km water depth in the Subantarctic Zone, indicating that poorest Southern Ocean ventilation occurred during the Last Glacial Maximum (~ 23–19 ka). Furthermore, trace metal results suggest that the vertical structure of the glacial Southern Ocean differed from modern deep water mass arrangement such that Lower Circumpolar Deep Water had lower O2 concentrations, and therefore was the likely reservoir of glacial CO2. |
format |
Text |
author |
Wagner, M. Hendy, I. L. |
author_facet |
Wagner, M. Hendy, I. L. |
author_sort |
Wagner, M. |
title |
Trace metal evidence for a poorly ventilated glacial Southern Ocean |
title_short |
Trace metal evidence for a poorly ventilated glacial Southern Ocean |
title_full |
Trace metal evidence for a poorly ventilated glacial Southern Ocean |
title_fullStr |
Trace metal evidence for a poorly ventilated glacial Southern Ocean |
title_full_unstemmed |
Trace metal evidence for a poorly ventilated glacial Southern Ocean |
title_sort |
trace metal evidence for a poorly ventilated glacial southern ocean |
publishDate |
2018 |
url |
https://doi.org/10.5194/cpd-11-637-2015 https://cp.copernicus.org/preprints/cp-2014-148/ |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Geographica Helvetica - geography eISSN: 1814-9332 |
op_relation |
doi:10.5194/cpd-11-637-2015 10670/1.ekr214 https://cp.copernicus.org/preprints/cp-2014-148/ |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/cpd-11-637-2015 |
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1766203795699662848 |