Light the way: The effect of light on cell density and chlorophyll production for Chlorella vulgaris, algae

Abstract

Chlorella vulgaris is a type of algae. Algae must undergo photosynthesis in order to grow and the growth can be seen in chlorophyll count and cell density. The amount of light being received plays a role in cell density and chlorophyll production. Because of this, it is believed that the bottle receiving the most light will be able to perform photosynthesis the most and therefore have the highest cell density and chlorophyll count. This led to the hypothesis that the bottle placed in the natural light/darkness will have the highest cell density and produce the most chlorophyll, followed by the bottle placed in the artificial light/darkness, followed by the bottle that had partial natural light penetration, and lastly, the bottle that was exposed to complete darkness. In order to test the hypothesis, we had four different bottles with algae, which were exposed to different levels of light. We covered one bottle in tinfoil, another in cheese cloth placed in natural light, one with no coverage in artificial light, and our control bottle placed in natural light with no coverage. The cell density and chlorophyll count will be measured at the beginning of each class for one minute, repeated three times for each trial using an AquaFlour and a spectrometer. We found that our hypothesis was not supported and that these findings differed between the two trials. This may be from different weather outside causing the plant to receive different light or it could be due to testing or human errors.