Phytoplankton is not only at the basis of the marine food chain but also an important buffer of climate changes, given that marine photosynthesis is responsible of 50% of the CO2 fixation on Earth. Despite their central roles in the Ocean, our understanding of the forces that shape the dynamics and structuration of phytoplankton communities is still limited by major methodological constraints in the marine environment. Prominent among them is the difficulty to simultaneously measure physiological responses from each microalga species within mixtures, which prevail in the Ocean. I recently developed an innovative approach based on a physical phenomenon, the Electro-Chromic Shift (ECS) of the photosynthetic pigments, to extract the photosynthetic responses of each species within an assembly. Photosynthesis is an ideal probe, i.e., a gateway to investigate both biotic interactions and abiotic stresses which are major determinants of the structuration of the phytoplankton community, because it is the prime target of those external factors.
Dans ce projet, la photosynthèse sera une sonde idéale pour étudier les forces façonnant les communautés phytoplanctoniques, puisqu’elle en est une cible principale. Le développement d’approches nouvelles permettant d’extraire les performances photosynthétiques de chaque micro-algue dans un mélange permettra d’étudier, au laboratoire et in situ, les mécanismes donnant naissance aux patrons écologiques observés dans l’Océan.
