FRESHWATER MICROALGAE

This study investigated the effects of different urea concentrations on the growth of Chlorella vulgaris and Scenedsemus, two freshwater microalgae species were analyzed under laboratory conditions. The experiment involved subjecting the microalgae to varying concentration of urea (Control, 10%, 20%, 40%, 60%, 80% and 100%). Absorbance was measured using a 721-visible Spectrophotometer at 750nm. Physicochemical parameters such as pH, turbidity, dissolved oxygen, conductivity and total dissolved solids were analyzed. Data was evaluated using descriptive statistics, two way analysis of variance and t-tests analysis and was conducted in Microsoft Excel 2010. Results revealed significant variation in the growth responses of both microalgae. Chlorella vulgaris exhibited optimal growth at 20% and 40% urea concentration with lowest growth occurring at higher concentrations. Scendesmus, on the other hand had the highest growth at 20% urea concentration with extremely low growth at higher levels. This infers that Chlorella vulgaris was more tolerant to higher concentrations of urea and ammonia toxicity than Scenedesmus. All physicochemical parameters and growth showed significant differences across concentrations of urea apart from Turbidity