The Effects of Increased Urea Concentrations on Chlorella vulgaris Growth

Abstract

Algae are eukaryotes that use photosynthesis to convert light energy into chemical energy, as well as other products, such as biodiesel. In our experiment, we tested whether the addition of a nutrient, in this case urea, has an effect on algae growth. We hypothesize a solution containing the highest concentration of urea will cause the most growth in the algae because it will contain the most nutrients, specifically the highest amount of nitrogen atoms. To test this hypothesis, we built a photobioreactor and had three experimental bottles, containing 20 μL, 40 μL, and 60 μL of urea. We counted the initial and final cell count to measure the difference in growth of the algae, as well as measuring the amount of chlorophyll produced. With the data that was collected, it was shown that the control had the highest amount of chlorophyll, in comparison to the algae with the urea concentrations added. In addition, the algae with the 40 μL urea concentration had the highest cell count growth compared to the algae containing 20 μL and 60 μL of urea. Therefore, our hypothesis was not supported.