Photoacclimation of Dunaliella tertiolecta (Chlorophyceae) under fluctuating irradiance

We investigated photoacclimation of Dunaliella tertiolecta (Butcher) in irradiance (I) regimes simulating mixed layer conditions of turbid estuarine waters or lakes. D. tertiolecta was exposed to a range of fixed I regimes to establish baseline physiology-I relationships that were compared with subsequent photoacclimation to a simulated mixed layer. Measured indices of photoacclimation included cellular pigmentation, chlorophyll variable fluorescence, and effective photosystem 2 antenna size. While D. tertiolecta grown under fluctuating I maintained division rates comparable to cells grown at high I, the cells exhibited characteristics of photoacclimation consistent with cells grown under a stable regimes at irradiances considerably lower than the average I of the simulated mixed layer.