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. tertiolectawas exposed to a range of fixed Iregimes to establish baseline physiology-Irelationships 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. tertiolectagrown under fluctuating Imaintained 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 Iof the simulated mixed layer.