SST-pattern in the North Atlantic reveals pronounced differences during MIS 11 and the Holocene


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ekandiano [ at ] ifm-geomar.de

Abstract

Sea surface temperatures (SST) from planktic foraminiferal assemblages and alkenones were reconstructed to compare interglacial climate dynamics of MIS 11 and the Holocene using meridional North-Atlantic transect of five sites: ODP 958 (off NW Africa), ODP 975 (western Mediterranean Sea), M23414 (subpolar NE Atlantic), MD992277 (Polar NE Atlantic) and M23063 (Polar NE Atlantic). SST reconstructions were supported by benthic and planktic O- and C-isotope records and, at subpolar and polar sites, by IRD content. In addition, foraminiferal abundances of certain environmental indicators were analyzed.According to our reconstruction quite different SST pattern in the North Atlantic existed during MIS 11 when compared to the Holocene. Averaged temperature results indicate that off Africa and in the Mediterranean sea SST were 1 °C to 2°C higher during MIS 11 than during the Holocene. By contrary, in the Nordic seas planktic foraminiferal abundances reveal much less intensive warm water advection into the region during the earlier period. Alkenone SSTs here, however, have comparable values during MIS 11 and the Holocene. The contradiction between alkenone and foraminiferal data in the Nordic seas might be explained by the different depth habitats of the organisms: coccolithophorides inhabit the uppermost 10 m depth layer and respond strongly to surface stratification while planktic foraminifera live deeper. By analogy with modern polar environments we consider that in the Nordic seas foraminiferal abundances better represent actual Atlantic water masses below the surface layer. In the subpolar NE Atlantic both SST sets exhibit close values during MIS 11 and the Holocene.



Item Type
Conference (Poster)
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Not peer-reviewed
Publication Status
Published
Event Details
AGU Fall Meeting, Dec 14 - Dec 18, 2009, San Francisco, USA, PP01..
Eprint ID
21010
Cite as
Kandiano, E. S. , Bauch, H. A. , Fahl, K. , Helmke, J. P. and Röhl, U. (2009): SST-pattern in the North Atlantic reveals pronounced differences during MIS 11 and the Holocene , AGU Fall Meeting, Dec 14 - Dec 18, 2009, San Francisco, USA, PP01. .


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