Haslea sp. is a microalga diatom genus which produces a unique blue-green pigment, the marennine. Marennine is used to colour oysters (‘Label Rouge Marennes-Oléron’) and it shows a strong potential for diverse applications in marine biotechnologies. Haslea species originate from widespread geographic locations. They present different autecological pigmentation and physiological traits, which could be used to optimise their growing in solar photobioreactors, and thereby select strains for biotech applications. In order to better understand Haslea spp. photoadaptation capacities and photoacclimation strategies, we will compare Haslea species and strains originating from different latitudes, i.e. temperate, tropics and arctic.