Marine Isotope Stage 11 in the Pacific Southern Ocean; a coccolithosphore perspective

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This project aims to get new insights into the late Pleistocene interglacial Marine Isotope Stage (MIS 11) in the Pacific sector of the Southern Ocean, where little information is available. MIS 11 (between ca. 424 and 374 kyr) is a unique exceptionally long interglacial period often regarded as an analogue of what the Holocene would have been without any anthropogenic interference. Thick white layers with high carbonate content have been observed at high southern latitudes during this time interval. We intend to elaborate an integrated, multi-parameter record of coccolithophore data on MIS 11 sediments retrieved during R/V Polarstern ANT XXVI/2 expedition in the polar South Pacific (cores PS75/091, PS75/079, PS75/076, PS75/059, PS75/047 and PS75/046). In order to characterize the coccolithophore palaeoproductivity two independent proxies will be used: the Nannofossil Accumulation Rate (NAR) and the coccolith Sr/Ca ratio measured in different coccolith size fractions. In addition, the carbonate contribution of the main species Gephyrocapsa caribbeanica to the total pelagic carbonate production will be assessed and the carbonate dissolution quantified. All the information retrieved will allow us to evaluate if the coccolithophores modified the equilibrium of the inorganic carbon system during MIS 11 in the Pacific sector Southern Ocean.