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| Titel |
Sensitivity of Red Sea circulation to sea level and insolation forcing during the last interglacial |
| VerfasserIn |
G. Trommer, M. Siccha, E. J. Rohling, K. Grant, M. T. J. Meer, S. Schouten, U. Baranowski, M. Kucera |
| 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 ; 7, no. 3 ; Nr. 7, no. 3 (2011-08-30), S.941-955 |
| Datensatznummer |
250004620
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| Publikation (Nr.) |
 copernicus.org/cp-7-941-2011.pdf |
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| Zusammenfassung |
| This study investigates the response of Red Sea circulation to sea level and
insolation changes during termination II and across the last interglacial,
in comparison with termination I and the Holocene. Sediment cores from the
central and northern part of the Red Sea were investigated by
micropaleontological and geochemical proxies. The recovery of the planktic
foraminiferal fauna following high salinities during marine isotopic stage (MIS) 6 took place at
similar sea-level stand (~50 m below present day), and with a similar
species succession, as during termination I. This indicates a consistent
sensitivity of the basin oceanography and the plankton ecology to sea-level
forcing. Based on planktic foraminifera, we find that increased water
exchange with the Gulf of Aden especially occurred during the sea-level
highstand of interglacial MIS 5e. From MIS 6 to the peak of MIS 5e, northern
Red Sea sea surface temperature (SST) increased from 21 °C to 25 °C, with about 3 °C of
this increase taking place during termination II. Changes in planktic
foraminiferal assemblages indicate that the development of the Red Sea
oceanography during MIS 5 was strongly determined by insolation and monsoon
strength. The SW Monsoon summer circulation mode was enhanced during the
termination, causing low productivity in northern central Red Sea core KL9,
marked by high abundance of G. sacculifer, which – as in the Holocene – followed summer
insolation. Core KL11 records the northern tip of the intruding intermediate
water layer from the Gulf of Aden and its planktic foraminifera fauna shows
evidence for elevated productivity during the sea-level highstand in the
southern central Red Sea. By the time of MIS 5 sea-level regression,
elevated organic biomarker BIT values suggest denudation of soil organic
matter into the Red Sea and high abundances of G. glutinata, and high reconstructed
chlorophyll-a values, indicate an intensified NE Monsoon winter circulation
mode. Our results imply that the amplitude of insolation fluctuations, and
the resulting monsoon strength, strongly influence the Red Sea oceanography
during sea-level highstands by regulating the intensity of water exchange
with the Gulf of Aden. These processes are responsible for the observation
that MIS 5e/d is characterized by higher primary productivity than the
Holocene. |
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