Radiocarbon Evidence for the Contribution of the Southern Indian Ocean to the Evolution of Atmospheric CO2 Over the Last 32,000 Years
It is widely assumed that the ventilation of the Southern Ocean played a crucial role in driving glacial-interglacial atmospheric CO2 levels. So far, however, ventilation records from the Indian sector of the Southern Ocean are widely missing. Here we present reconstructions of water residence times...
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ftdatacite:10.23689/fidgeo-4450 2023-05-15T18:25:03+02:00 Radiocarbon Evidence for the Contribution of the Southern Indian Ocean to the Evolution of Atmospheric CO2 Over the Last 32,000 Years Ronge, Thomas A. Prange, Matthias Mollenhauer, Gesine Ellinghausen, Maret Kuhn, Gerhard Tiedemann, Ralf 2020 https://dx.doi.org/10.23689/fidgeo-4450 https://e-docs.geo-leo.de/handle/11858/8796 en eng FID GEO Article article-journal Text ScholarlyArticle 2020 ftdatacite https://doi.org/10.23689/fidgeo-4450 2022-02-08T12:04:14Z It is widely assumed that the ventilation of the Southern Ocean played a crucial role in driving glacial-interglacial atmospheric CO2 levels. So far, however, ventilation records from the Indian sector of the Southern Ocean are widely missing. Here we present reconstructions of water residence times (depicted as ΔΔ14C and Δδ13C) for the last 32,000 years on sediment records from the Kerguelen Plateau and the Conrad Rise (~570- to 2,500-m water depth), along with simulated changes in ocean stratification from a transient climate model experiment. Our data indicate that Circumpolar Deep Waters in the Indian Ocean were part of the glacial carbon pool. At our sites, close to or bathed by upwelling deep waters, we find two pulses of decreasing ΔΔ14C and δ13C values (~21–17 ka; ~15–12 ka). Both transient pulses precede a similar pattern in downstream intermediate waters in the tropical Indian Ocean as well as rising atmospheric CO2 values. These findings suggest that 14C-depleted, CO2-rich Circumpolar Deep Water from the Indian Ocean contributed to the rise in atmospheric CO2 during Heinrich Stadial 1 and also the Younger Dryas and that the southern Indian Ocean acted as a gateway for sequestered carbon to the atmosphere and tropical intermediate waters. Text Southern Ocean DataCite Metadata Store (German National Library of Science and Technology) Conrad Rise ENVELOPE(41.000,41.000,-53.000,-53.000) Indian Kerguelen Southern Ocean |
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Open Polar |
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DataCite Metadata Store (German National Library of Science and Technology) |
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ftdatacite |
language |
English |
description |
It is widely assumed that the ventilation of the Southern Ocean played a crucial role in driving glacial-interglacial atmospheric CO2 levels. So far, however, ventilation records from the Indian sector of the Southern Ocean are widely missing. Here we present reconstructions of water residence times (depicted as ΔΔ14C and Δδ13C) for the last 32,000 years on sediment records from the Kerguelen Plateau and the Conrad Rise (~570- to 2,500-m water depth), along with simulated changes in ocean stratification from a transient climate model experiment. Our data indicate that Circumpolar Deep Waters in the Indian Ocean were part of the glacial carbon pool. At our sites, close to or bathed by upwelling deep waters, we find two pulses of decreasing ΔΔ14C and δ13C values (~21–17 ka; ~15–12 ka). Both transient pulses precede a similar pattern in downstream intermediate waters in the tropical Indian Ocean as well as rising atmospheric CO2 values. These findings suggest that 14C-depleted, CO2-rich Circumpolar Deep Water from the Indian Ocean contributed to the rise in atmospheric CO2 during Heinrich Stadial 1 and also the Younger Dryas and that the southern Indian Ocean acted as a gateway for sequestered carbon to the atmosphere and tropical intermediate waters. |
format |
Text |
author |
Ronge, Thomas A. Prange, Matthias Mollenhauer, Gesine Ellinghausen, Maret Kuhn, Gerhard Tiedemann, Ralf |
spellingShingle |
Ronge, Thomas A. Prange, Matthias Mollenhauer, Gesine Ellinghausen, Maret Kuhn, Gerhard Tiedemann, Ralf Radiocarbon Evidence for the Contribution of the Southern Indian Ocean to the Evolution of Atmospheric CO2 Over the Last 32,000 Years |
author_facet |
Ronge, Thomas A. Prange, Matthias Mollenhauer, Gesine Ellinghausen, Maret Kuhn, Gerhard Tiedemann, Ralf |
author_sort |
Ronge, Thomas A. |
title |
Radiocarbon Evidence for the Contribution of the Southern Indian Ocean to the Evolution of Atmospheric CO2 Over the Last 32,000 Years |
title_short |
Radiocarbon Evidence for the Contribution of the Southern Indian Ocean to the Evolution of Atmospheric CO2 Over the Last 32,000 Years |
title_full |
Radiocarbon Evidence for the Contribution of the Southern Indian Ocean to the Evolution of Atmospheric CO2 Over the Last 32,000 Years |
title_fullStr |
Radiocarbon Evidence for the Contribution of the Southern Indian Ocean to the Evolution of Atmospheric CO2 Over the Last 32,000 Years |
title_full_unstemmed |
Radiocarbon Evidence for the Contribution of the Southern Indian Ocean to the Evolution of Atmospheric CO2 Over the Last 32,000 Years |
title_sort |
radiocarbon evidence for the contribution of the southern indian ocean to the evolution of atmospheric co2 over the last 32,000 years |
publisher |
FID GEO |
publishDate |
2020 |
url |
https://dx.doi.org/10.23689/fidgeo-4450 https://e-docs.geo-leo.de/handle/11858/8796 |
long_lat |
ENVELOPE(41.000,41.000,-53.000,-53.000) |
geographic |
Conrad Rise Indian Kerguelen Southern Ocean |
geographic_facet |
Conrad Rise Indian Kerguelen Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_doi |
https://doi.org/10.23689/fidgeo-4450 |
_version_ |
1766206193027514368 |