Agricultural fertilizers as alternative culture media for biomass production of Chondracanthus squarrulosus (Rhodophyta, Gigartinales) under semi-controlled conditions

The red alga Chondracanthus squarrulosus was cultured under semi-controlled conditions to evaluate growth (biomass production) with agricultural fertilizers (ammonium nitrate, ammonium sulphate and urea) vs. analytical grade inorganic salts; sodium nitrate (analytical grade) and seawater were used as controls. The concentration of each agricultural fertilizer used was 1.95 mg l^?1 week^?1. Growth of C. squarrulosus with agricultural fertilizers and sodium nitrate as control showed no significant differences (P<0.05). A maximum growth of 5.4% per day and thallus nitrogen content of 3.4% dry weight were obtained with ammonium sulphate. The results suggest that commercial agricultural fertilizers can be substituted for analytical grade nutrients with no significant effect on the culture.