Research focus Efficient light utilization and thus proper acclimation to varying light conditions is essential for the competitiveness and survival of photosynthetic organisms. We investigate the light acclimation of the photosynthetic apparatus in land plants and algae. Applying chlorophyll fluorescence and absorption spectroscopy, our research is focused on the regulation and function of photoprotective mechanisms (e.g. energy dissipation) and the adjustment of photosynthetic light utilization to fluctuating light conditions.