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| Titel |
Hydrographic changes in the Agulhas Recirculation Region during the late Quaternary |
| VerfasserIn |
D. K. Naik, R. Saraswat, N. Khare, A. C. Pandey, R. Nigam |
| 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 ; 10, no. 2 ; Nr. 10, no. 2 (2014-04-15), S.745-758 |
| Datensatznummer |
250116950
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| Publikation (Nr.) |
 copernicus.org/cp-10-745-2014.pdf |
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| Zusammenfassung |
| The strength of Southern Hemisphere westerlies, as well as the positions of
the subtropical front (STF), Agulhas Current (AC) and Agulhas Return Current
(ARC) control the hydrography of the southwestern Indian Ocean. Although
equatorward migration of the STF and reduction in Agulhas leakage were
reported during the last glacial period, the fate of ARC during the last
glacial–interglacial cycle is not clear. Therefore, in order to understand
changes in the position and strength of ARC during the last
glacial–interglacial cycle, here we reconstruct hydrographic changes in the
southwestern Indian Ocean from temporal variation in planktic foraminiferal
abundance, stable isotopic ratio (δ18O) and trace elemental ratio
(Mg/Ca) of planktic foraminifera Globigerina bulloides in a core
collected from the Agulhas Recirculation Region (ARR) in the southwestern
Indian Ocean. Increased abundance of G. bulloides suggests that the
productivity in the southwestern Indian Ocean increased during the last glacial
period which confirms previous reports of high glacial productivity in the Southern Ocean. The
increased productivity was likely driven by the intensified Southern
Hemisphere westerlies supported by an equatorward migration of the
subtropical front. Increase in relative abundance of Neogloboquadrina
incompta suggests seasonally strong thermocline and enhanced advection of
southern source water in the southwestern Indian Ocean as a result of
strengthened ARC, right through MIS 4 to MIS 2, during the last glacial
period. Therefore, it is inferred that over the last glacial–interglacial
cycle, the hydrography of the southwestern Indian Ocean was driven by
strengthened westerlies, ARC as well as a migrating subtropical front. |
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