Coccolithophores,among which Emiliania huxleyi (E.huxleyi) is the most abundant and widespread species,are considered to be the most productive calcifying organism on Earth.They play a key role in the marine carbon cycle because of their calcite production (in the form of coccoliths) and their subsequent sinking to the ocean floor.Like other phytoplanktonic species,the coccolithophores produce transparent exopolymer particles (TEP) that promote the aggregation of biogenic particles produced in surface oceans,and therefore contribute to the export of carbon to deep waters.The rise of atmospheric pCO2 and the consequent ocean acidification could modify the ecology of coccolithophores,which in turn would have an impact on the production,transformation and fate of carbon in the surface layer of the ocean.