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| Titel |
Quantifying the roles of ocean circulation and biogeochemistry in governing ocean carbon-13 and atmospheric carbon dioxide at the last glacial maximum |
| VerfasserIn |
A. Tagliabue, L. Bopp, D. M. Roche, N. Bouttes, J.-C. Dutay, R. Alkama, M. Kageyama, E. Michel, D. Paillard |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 5, no. 4 ; Nr. 5, no. 4 (2009-11-18), S.695-706 |
| Datensatznummer |
250002698
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| Publikation (Nr.) |
 copernicus.org/cp-5-695-2009.pdf |
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| Zusammenfassung |
| We use a state-of-the-art ocean general circulation and
biogeochemistry model to examine the impact of changes in ocean
circulation and biogeochemistry in governing the change in ocean
carbon-13 and atmospheric CO2 at the last glacial maximum
(LGM). We examine 5 different realisations of the ocean's
overturning circulation produced by a fully coupled atmosphere-ocean
model under LGM forcing and suggested changes in the atmospheric
deposition of iron and phytoplankton physiology at the LGM. Measured
changes in carbon-13 and carbon-14, as well as a qualitative
reconstruction of the change in ocean carbon export are used to
evaluate the results. Overall, we find that while a reduction in
ocean ventilation at the LGM is necessary to reproduce carbon-13 and
carbon-14 observations, this circulation results in a low net sink
for atmospheric CO2. In contrast, while biogeochemical
processes contribute little to carbon isotopes, we propose that most
of the change in atmospheric CO2 was due to such factors.
However, the lesser role for circulation means that when all
plausible factors are accounted for, most of the necessary CO2
change remains to be explained. This presents a serious challenge to
our understanding of the mechanisms behind changes in the global
carbon cycle during the geologic past. |
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