Ocean surface water response to short-term climate changes revealed by coccolithophores from the Gulf of Cadiz (NE Atlantic) and Alboran Sea (W Mediterranean).

Colmenero-Hidalgo, E., Flores, J.-A., Sierro, F.J., Bárcena, M., Löwemark, L., Schönfeld, Joachim and Grimalt, J. (2004) Ocean surface water response to short-term climate changes revealed by coccolithophores from the Gulf of Cadiz (NE Atlantic) and Alboran Sea (W Mediterranean). Palaeogeography Palaeoclimatology Palaeoecology, 205 . pp. 317-336. DOI 10.1016/j.palaeo.2003.12.014.

[img] Text
Colmenero-Hidalgo.pdf - Reprinted Version
Restricted to Registered users only

Download (1353Kb) | Contact

Supplementary data:

Abstract

The response of coccolithophore assemblages to short-term millennial and centennial climatic changes over the last 50 kyr is studied in core M39029-7 from the Gulf of Cadiz (Atlantic Ocean) and core MD95-2043 from the Alboran Sea (Western Mediterranean Sea). The nannoplankton data are compared with oxygen isotopes, U37k′-SST and other biogeochemical and sedimentological proxies to obtain a new perspective of the paleoceanography and paleoecology of the area during these short-term climatic changes. Coccolithophores indicate that Heinrich events (HE) were characterised by the presence of cold, low salinity and turbid water masses on both sides of the Strait of Gibraltar. High abundances of the Lower Photic Zone (LPZ) species Florisphaera profunda in the Gulf of Cadiz synchronous with HE are interpreted as being an evidence of upper water-column stratification on the Atlantic side. These episodes coincided with input of terrigenous material, especially during H2. Surface waters during Dansgaard-Oeschger (DO) Stadials were also cold and turbid, while most of DO Interstadials were characterised by warm-water flora. The increase in small placoliths (small Gephyrocapsa and Emiliania huxleyi (<4 μm)) reveals a higher coccolithophore production during DO Interstadials and the Holocene. Conversely, HE and most of DO Stadials show peaks of E. huxleyi (>4 μm), which is considered here as a cold-water indicator. The sharp decrease in large specimens of E. huxleyi related to the warming trend in the last deglaciation can be used as a biostratigraphic reference level that marks—at least approximately—the deglaciation and the beginning of the Holocene. Peaks of F. profunda are observed during Termination 1 (T1) in the Alboran Sea. They are isochronous with the “Organic-Rich Layer 1” recognised in the Western Mediterranean. In this interval, the water column of the region was stratified as a consequence of the global increase in the sea level following the deglaciation. Quantitative analyses of the coccolithophore assemblage allow us to interpret that coccolithophore production has been higher in the Alboran Sea than in the Gulf of Cadiz during the Holocene.

Document Type: Article
Keywords: Coccoliths; Heinrich events; Dansgaard-Oeschger cycles; Paleo-oceanography; Gulf of Cadiz; Alboran Sea; Western Mediterranean; Holocene; Pleistocene; core M39029-7
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1016/j.palaeo.2003.12.014
ISSN: 0031-0182
Date Deposited: 19 Mar 2009 14:38
Last Modified: 26 Jan 2017 12:50
URI: http://oceanrep.geomar.de/id/eprint/2455

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...