Eco physiological consequences of fluctuating light on phytoplankton Phytoplankton growth depends not only on the mean intensity but also on the dynamics of the light supply. The nonlinear light dependency of growth is characterized by a small number of basic parameters: the compensation light intensity PARcompμ where production and losses are balanced the growth efficiency at sub saturating light αµ and the maximum growth rate at saturating light µmax. In surface mixed layers phytoplankton may rapidly move between high light intensities and almost darkness. Because of the different frequency distribution of light and or acclimation processes the light dependency of growth may differ between constant and fluctuating light. Very few studies measured growth under fluctuating light at a sufficient number of mean light intensities to estimate the parameters of the growth irradiance relationship. Hence the influence of light dynamics on µmax αµ and PARcompμ are still largely unknown. By extension accurate modelling predictions of phytoplankton development under fluctuating light exposure remain ...