Assessment of sea surface temperature changes in the Gulf of Cadiz during the last 30 ka: implications for glacial changes in the regional hydrography

Type Article
Date 2011
Language English
Author(s) Penaud Aurelie1, 2, Eynaud F.2, Voelker A.3, Kageyama M.4, Marret F.5, Turon J. L.2, Blamart D.4, Mulder T.2, Rossignol L.2
Affiliation(s) 1 : IUEM UBO, Domaines Ocean UMR6538, F-29280 Plouzane, France.
2 : Univ Bordeaux 1, EPOC UMR5805, F-33405 Talence, France.
3 : LNEG, Unidade Geol Marinha, P-2610143 Zambujal, Amadora, Portugal.
4 : Ctr Etud Saclay, LSCE, F-91191 Gif Sur Yvette, France.
5 : Univ Liverpool, Sch Environm Sci, Liverpool L69 7ZT, Merseyside, England.
Source Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2011 , Vol. 8 , N. 8 , P. 2295-2316
DOI 10.5194/bg-8-2295-2011
WOS© Times Cited 19
Abstract New dinocyst analyses were conducted on core MD99-2339 retrieved from the central Gulf of Cadiz. Dinocyst and foraminiferal assemblages from this core are combined with existing data off SW Portugal and NW Morocco to investigate past hydrological and primary productivity regimes in the subtropical NE Atlantic Ocean over the last 30 ka. Our results have revealed highest upwelling intensity during Heinrich Stadial 1 (HS 1) and the Younger Dryas and weaker upwelling cells during the Last Glacial Maximum (LGM) and HS 2, off the SW Iberian and NW Moroccan margins. Similar assemblages between the Gulf of Cadiz and the NW Moroccan margin, and distinct species off Portugal, were observed during the cold climatic extremes that punctuated the last 30 ka. This pattern has been linked to the occurrence of a hydrological structure between SW Iberia and Cadiz during the last glacial period, perhaps similar to the modern Azores Front. This front was probably responsible locally for heterotrophic dinocysts found in the Gulf of Cadiz during the last glacial period, even if this sector is not conductive to upwelling phenomena by Ekman transport. Regional reconstructions of paleo-sea-surface temperatures (SSTs) using dinocyst and foraminiferal transfer functions, as well as alkenones, are also discussed and depict coherent scenarios over the last 30 ka. Seasonal reconstructions of LGM SSTs obtained with this multi-proxy panel are discussed jointly with model outputs in order to contribute to ongoing efforts in model-data comparison.
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Penaud Aurelie, Eynaud F., Voelker A., Kageyama M., Marret F., Turon J. L., Blamart D., Mulder T., Rossignol L. (2011). Assessment of sea surface temperature changes in the Gulf of Cadiz during the last 30 ka: implications for glacial changes in the regional hydrography. Biogeosciences, 8(8), 2295-2316. Publisher's official version : https://doi.org/10.5194/bg-8-2295-2011 , Open Access version : https://archimer.ifremer.fr/doc/00230/34125/