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Coccolithophores paleoproductivity

Why study coccolithophores?

Coccolithophores are unicellular marine eukariotic algae, one of the main marine phytoplankton groups, and among the most important pelagic calcifying organisms.
They play a key role in the ocean biogeochemistry and ecosystem, as primary producers and calcifiers, due to their abundance and fast turnover rates.
Coccolithophores cover their cell with coccoliths, minute calcite plates (between 2 to 20 micra). Coccoliths get loosen and deposited in the sediments after the coccolithophore death. These coccoliths contain information on the paleoceanographic conditions of when the coccolithophore lived, on the composition of the overlying photic zone’s community, and also their calcification rate.

Primary productivity is a contributor to the decrease of pCO2 during glacial periods. Coccolithophores are linked to the carbon cycle in two ways: by synthetizing organic matter (biological pump) an by building their calcite coccoliths (carbonate pump). The understanding of coccolithophores’ role, as a phytoplankton functional group and their productivity variability, is important for their integration into climatic models and can ultimately lead to a better understanding of Earth’ biogeochemical cycles.
Fig.1 Coccoliths from the Iberian margin (IODP Site U1385).

The main objectives of this study are:

1. to characterise coccolithophores productivity from MIS 16 to 11 (650 to 350 kyr ago) in the mid North Atlantic ocean - IODP Site U1313;

2. to characterise coccolithophores productivity from MIS 12 to 11 (500 to 350 kyr ago) in the Iberian margin on two different sites - IODP Site U1385, also know as the Shackleton site, and IODP Site U1391, closer to shore and under higher upwelling influence.