1 NOVEMBER 1999

E. Valenzuela-Espinoza, R. Nunez-Millan, F. Nunez-Cebrero-1999

Aquacultural Engineering, 20(3): 135-147 (from Current Contents)

Abstract:

Biomass production and uptake of nitrate, phosphate and ammonium were determined in batch culture of the marine microalgae Isochrysis aff. galbana (Clone T-ISO) for 7 days comparing an agricultural fertilizer media with the f/2 media. The average cellular density obtained with the f/2 media and the agricultural fertilizer showed no significant difference (P > 0.05) (average growth rate of 0.43 and 0.42 per day, respectively). During the first 4 days, the phosphate in the agricultural fertilizer media was consumed ten times faster than in the f/2 media. When nitrate and ammonium were added together, the ammonium was consumed eight times faster than the nitrate in a period of 5 days. Below concentrations of 1.36 mu M of ammonium, nitrate began to be consumed. The nitrate uptake in the f/2 media increased substantially (to 555 mu M) from the fourth to the seventh day of culture. The cost of the f/2 media is eight times more expensive than that prepared with agricultural fertilizer. We conclude that agricultural fertilizer did not have a negative effect compared to f/2 on the growth rate of IT. aff. galbana (Clone T-ISO), produced the same amount of biomass as the f/2 media, and was much cheaper. The alternate media shows great potential for use in aquaculture for I. aff. galbana (clone T-ISO) production.

(Univ Autonoma Baja California, Fac Ciencias Marinas, Apartado Postal 453, Ensenada, Baja California, Mexico, e-mail of R. Millan-Nunez: rmillan@faro.ens.uabc.mx)
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