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Development of new proxies to assess the 20th century variability of the North West Africa upwelling.

Alkenone unsaturation index (UK’37) recorded an unprecedented cooling during the 20th century in several coastal upwellings among which the one of Cape Ghir off the coast of Morocco (McGregor et al., 2007), presumably as a result of increase land-ocean thermal contrast and wind intensification. It may continue to intensify as global warming and atmospheric CO2 levels increase. The recent variability of the Senegal-Mauritanian upwelling (NW Africa) will be studied because of the likelihood of dramatic ecosystem and socioeconomic impacts. The mechanisms leading to the incorporation of these elements in the calcite during the biocalcification will be explored using coccolithophorids cultures. Coccoliths buried in surface sediments of the Senegal upwelling and extra-tropical latitudes will be also analyzed for cross-comparison with results obtained from cultures over similar range of T and pH to evaluate the ability of these proxies to record SST and surface-pH. Elemental ratios and bor

Date de debut : 04 February 2015
Date de fin : 06 February 2015
Lieu : Brest
Type : Colloque
Mise en ligne par : NDIAYE Ada