The fate of photosynthetic organisms is not only determined by their ability to respond to abiotic changes (see theme 1) but also by biotic interactions. We developed recently new approaches allowing the deconvolution of photosynthetic performances in mixtures. In this task, we use this approach to study the allelopathic interactions (allelopathy: release of toxic secondary metabolites) and the competition for nutrients within phytoplankton assemblages. We also investigate the physiological response of diverse phytoplankton species to viral infections (coccolithophores, diatoms, cyanobacteria).
