Growth rates of phytoplankton under fluctuating light

1 The effect of light fluctuations on the growth rates of four species of freshwater phytoplankton was investigated. Experimental light regimes included constant irradiance and fluctuations of a step function form, with equal proportion of high (maximum of 240 µmol photons m-2 s-1) and low light (minimum of 5 µmol photons m-2 s-1) (or dark) in a period. Fluctuations of 1, 8 and 24-h periods were imposed over several average irradiances (25, 50,...