Growth rate, maintenance energy and pigmentation of planktonic Cyanophyta during one-hour light: Dark cycles

Three planktonic Cyanophyta, Oscillatoria redekei, O. agardhii and Aphanizomenon flosaquae f. gracile were grown at 15, 10 and 6°C over a range of light:dark (L:D) cycles with a total cycle time of 1 h. At 15°C, growth rate was saturated at a L:D ratio of 1:1 in both Oscillatoria species, and at 5:1 in Aphanizomenon. With decreasing temperature, the saturating L:D ratio decreased in all cases. Photosynthetic pigments increased with decreasing light dose down to a L:D ratio of 1:5, but at 1:11 a decline in pigmentation occurred. Oscillatoria redekei showed enhanced phycoerythrin synthesis under the lowest light fraction.