Does temperature shift justify microalgae production under greenhouse?

International audienceWe analyze the influence of greenhouses in the cultivation of phytoplankton. For this we propose a model for the marine green algae Tetraselmis suecica, and adapt it to four other species (Spirulina platensis, Dunaliella salina, Phaeodactylum tricornutum and Chlorella vulgaris). Experiments under a greenhouse were carried out for the marine green algae Tetraselmis suecica, shifting the temperature of two raceways compared to a reference raceway with free evolving temperature. The productivity model was then parametrized and validated accounting for the recorded evolution of temperature and light. The yearly raceway pond production and the benefit of greenhouse usage were assessed under different scenarios for the five considered species. At year scale, greenhouse efficiency is notable only for few species, e.g. Spirulina platensis, where productivity can be increased by 20%. Based on these results, cultivation under greenhouse is beneficial mainly to protect the culture against contamination and to increase productivity in cold regions for species susceptible to photoinhibition with optimal growth in high temperatures. Rotation of the cultivated species is also a good strategy to improve annual productivity