Coccolithophores are single-celled marine algae that surround themselves with tiny, highly structured limestone plates or coccoliths. They are responsible for most biogenic calcification or sediments in marine systems and are one of nature’s most prolific consumers of CO2. As CO2 levels rise, it is vital to characterise the effects on coccolithophores and the organisms’ geochemical impact on the environment. With the support of the Marie Skłodowska-Curie Actions programme, the Cocco-Next project will investigate the physiological and genetic acclimations of the coccolithophore life cycle phases to inhabit different ecological niches, holistically including both haploid and diploid life cycle phases.