Deepwater expansion and enhanced remineralization in the eastern equatorial Pacific during the last glacial maximum
Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography and Paleoclimatology 33 (2018): 563-578, doi:10.1029/2017PA003221. Published...
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Language: | English |
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/10511 2023-05-15T18:25:52+02:00 Deepwater expansion and enhanced remineralization in the eastern equatorial Pacific during the last glacial maximum Umling, Natalie E. Thunell, Robert C. Bizimis, Michael 2018-06-04 https://hdl.handle.net/1912/10511 en_US eng John Wiley & Sons https://doi.org/10.1029/2017PA003221 Paleoceanography and Paleoclimatology 33 (2018): 563-578 https://hdl.handle.net/1912/10511 doi:10.1029/2017PA003221 Paleoceanography and Paleoclimatology 33 (2018): 563-578 doi:10.1029/2017PA003221 Glacial Benthic foraminifera Circulation Cadmium Carbon isotopes Deglaciation Article 2018 ftwhoas https://doi.org/10.1029/2017PA003221 2022-05-28T23:00:28Z Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography and Paleoclimatology 33 (2018): 563-578, doi:10.1029/2017PA003221. Published estimates of the radiocarbon content of middepth waters suggest a decrease in ventilation in multiple locations during the last glacial maximum (LGM; 24.0–18.1 ka). Reduced glacial ventilation would have allowed respired carbon to accumulate in those waters. A subsequent deglacial release of this respired carbon reservoir to the atmosphere could then account for the observed increases in atmospheric CO2 and decline in atmospheric radiocarbon content. However, age model error and a release of 14C‐depleted mantle carbon have also been cited as possible explanations for the observed middepth radiocarbon depletions, calling into question the deep ocean's role in storing respired carbon during the LGM. Joint measurements of benthic foraminiferal carbon isotope values (δ13C) and cadmium/calcium (Cd/Ca) ratios provide a method for isolating the air‐sea component of a water mass from changes in remineralization. Here we use benthic foraminiferal δ13C and Cd/Ca records from the eastern equatorial Pacific to constrain changes in remineralization and water‐mass mixing over the last glacial‐interglacial transition. These records are complemented with elemental measurements of the authigenic coatings of foraminifera to monitor postdepositional changes in bottom water properties. Our results suggest an increase of deep waters at midwater depths consistent with a shoaling of the boundary between the upper and lower branches of Southern Ocean overturning circulation. Additionally, our records demonstrate increased organic matter remineralization in middepth waters during the LGM, suggesting that respired carbon did accumulate in middepth waters under periods of reduced ventilation. National Science foundation Grant Number: ... Article in Journal/Newspaper Southern Ocean Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Pacific Southern Ocean Paleoceanography and Paleoclimatology 33 6 563 578 |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
English |
topic |
Glacial Benthic foraminifera Circulation Cadmium Carbon isotopes Deglaciation |
spellingShingle |
Glacial Benthic foraminifera Circulation Cadmium Carbon isotopes Deglaciation Umling, Natalie E. Thunell, Robert C. Bizimis, Michael Deepwater expansion and enhanced remineralization in the eastern equatorial Pacific during the last glacial maximum |
topic_facet |
Glacial Benthic foraminifera Circulation Cadmium Carbon isotopes Deglaciation |
description |
Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography and Paleoclimatology 33 (2018): 563-578, doi:10.1029/2017PA003221. Published estimates of the radiocarbon content of middepth waters suggest a decrease in ventilation in multiple locations during the last glacial maximum (LGM; 24.0–18.1 ka). Reduced glacial ventilation would have allowed respired carbon to accumulate in those waters. A subsequent deglacial release of this respired carbon reservoir to the atmosphere could then account for the observed increases in atmospheric CO2 and decline in atmospheric radiocarbon content. However, age model error and a release of 14C‐depleted mantle carbon have also been cited as possible explanations for the observed middepth radiocarbon depletions, calling into question the deep ocean's role in storing respired carbon during the LGM. Joint measurements of benthic foraminiferal carbon isotope values (δ13C) and cadmium/calcium (Cd/Ca) ratios provide a method for isolating the air‐sea component of a water mass from changes in remineralization. Here we use benthic foraminiferal δ13C and Cd/Ca records from the eastern equatorial Pacific to constrain changes in remineralization and water‐mass mixing over the last glacial‐interglacial transition. These records are complemented with elemental measurements of the authigenic coatings of foraminifera to monitor postdepositional changes in bottom water properties. Our results suggest an increase of deep waters at midwater depths consistent with a shoaling of the boundary between the upper and lower branches of Southern Ocean overturning circulation. Additionally, our records demonstrate increased organic matter remineralization in middepth waters during the LGM, suggesting that respired carbon did accumulate in middepth waters under periods of reduced ventilation. National Science foundation Grant Number: ... |
format |
Article in Journal/Newspaper |
author |
Umling, Natalie E. Thunell, Robert C. Bizimis, Michael |
author_facet |
Umling, Natalie E. Thunell, Robert C. Bizimis, Michael |
author_sort |
Umling, Natalie E. |
title |
Deepwater expansion and enhanced remineralization in the eastern equatorial Pacific during the last glacial maximum |
title_short |
Deepwater expansion and enhanced remineralization in the eastern equatorial Pacific during the last glacial maximum |
title_full |
Deepwater expansion and enhanced remineralization in the eastern equatorial Pacific during the last glacial maximum |
title_fullStr |
Deepwater expansion and enhanced remineralization in the eastern equatorial Pacific during the last glacial maximum |
title_full_unstemmed |
Deepwater expansion and enhanced remineralization in the eastern equatorial Pacific during the last glacial maximum |
title_sort |
deepwater expansion and enhanced remineralization in the eastern equatorial pacific during the last glacial maximum |
publisher |
John Wiley & Sons |
publishDate |
2018 |
url |
https://hdl.handle.net/1912/10511 |
geographic |
Pacific Southern Ocean |
geographic_facet |
Pacific Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Paleoceanography and Paleoclimatology 33 (2018): 563-578 doi:10.1029/2017PA003221 |
op_relation |
https://doi.org/10.1029/2017PA003221 Paleoceanography and Paleoclimatology 33 (2018): 563-578 https://hdl.handle.net/1912/10511 doi:10.1029/2017PA003221 |
op_doi |
https://doi.org/10.1029/2017PA003221 |
container_title |
Paleoceanography and Paleoclimatology |
container_volume |
33 |
container_issue |
6 |
container_start_page |
563 |
op_container_end_page |
578 |
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1766207575580213248 |