|Altering growth and gross chemical composition of two microalgal molluscan food species by varying nitrate and phosphate|
In: Aquaculture. Elsevier: Amsterdam; London; New York; Oxford; Tokyo. ISSN 0044-8486; e-ISSN 1873-5622
Biochemische compositie; Fosfaten; Fytoplankton; Groei; Nitraten; Voedingsorganismen; Marien
Growth and gross chemical composition of two axenically cultured algal flagellates, Dunaliella tertiolecta and Tetraselmis maculata, were related to nitrate and phosphate concentrations in an enriched seawater medium. Population growth of test species in 28-day batch cultures was compared in 16 combinations of NaNO3 (77.5, 150, 300, and 350 mg/l) and KH2PO4 (5, 10, 20, and 25 mg/l) in an experiment of factorial design. Phosphate-P was not limiting to final populations of either alga at concentrations tested, and nitrate-N did not affect final population density of D. tertiolecta) at the lowest concentration. In contrast, final populations of T. maculata were considerably reduced in all media containing the lowest NaNO3 concentration, but maximal populations were achieved in 150 mg/l NaNO3. Maximal yields per unit volume were attained in the following NaNO3/KH2PO4 , as mg/l: T. maculata), dry weight and lipid - 300/5, protein - 300/20, carbohydrate - 77.5/5; D. tertiolecta, dry weight - 150/5, protein - 300/5, carbohydrate and lipid - 77.5/5.