Utilization of nitrate and phosphate by the green alga Tetraselmis gracilis Kylin

Abstract

Nutrient-depleted cells of Tetraselmis gracilis were grown in sea water containing different concentrations of nitrate and phosphate. Growth rate of cells was first studied by determining the growth constant (k) and generation time (tg). Enrichment with nitrate and phosphate either singly or in combination increased k and reduced tg values. Further studies on algal growth were made using the Monod model. Cell counts and 14C uptake were taken as indices of growth parameter (µ). Values of half saturation constant (Ks) and maximum growth rate (µ max) obtained from cell counts varied from those of 14C uptake. Certain modifications in the Monod model seem necessary for the study of algal ecology and these modifications should include multiple variability of the environment and the specific behaviour of the algae.