The growth rate, biomass production and composition of Chaetoceros sp grown with different light sources

The diatom Chaetoceros sp. was grown with a continuous photon flow rate of 125 mu mol m(-2) s(-1), provided by Cool White (CW), or by Gro-Lux and Gro-Lux wide spectrum agricultural lamps (GRO and GRO/WS). At the end of exponential and during stationary growth, these gave higher cell numbers and biomass than CW lamps. There were no differences in cell concentration and growth rates between GRO and GRO/WS-grown cultures, but biomass was significantly higher with GRO lamps. In all treatments, protein concentration was higher and lipids were lower at the end of exponential growth than in the stationary phase, but proteins remained consistently higher than other treatments with GRO lamps in both growth phases, possibly because of their high emission of blue light. CW gave the highest lipid and GRO/WS the best carbohydrate production during both phases of growth. This suggests that these consistent differences are caused by different spectral qualities of light, that could be used to obtain different live diets for aquaculture, varying the time of harvest and the type of light sources. (c) 2005 Elsevier B.V. All rights reserved.