The Slow Growth of Chlamydomonas reinhardtii

Abstract

Chlamydomonas reinhardtii is a green unicellular algae that plays a significant role in the aquatic food chain and in particular, as a food source for many salmon species. C. reinhardtii is a unique organism that can grow through both photosynthesis as well as heterotrophic means by absorbing nutrients through their cell surface. Recent studies have used C. reinhardtii in fixing CO2 due to their rapid photosynthetic capabilities. The focus of our study was to determine how different light wavelengths influence the growth patterns of C. reinhardtii for use in green technology. In particular, three light wavelengths were used to examine the growth rate of C. reinhardtii. The control used for this study was a white light treatment which was compared against the red and blue light treatments. Red light has a longer wavelength compared to blue light, whereas white light comprises all the wavelengths in the visible spectrum. This study was conducted over a 10 day growth period, where samples were collected every two to three days for a total of four sampling days. A hemocytometer was used to conduct the cell counts over the duration of this study and these values were used to determine the growth rate of C. reinhardtii. A one-way ANOVA test was used to analyze the overall growth rates of C. reinhardtii to determine if there were any significant differences in the growth rate between treatments. Growth rates for the white light, red light, and blue light treatment yielded averages of 0.0114 [cells/mL]/day, 0.1793 [cells/mL]/day, and 0.1047 [cells/mL]/day respectively. The statistical analysis yielded a p-value greater than 0.05, indicating that there was no difference found between the growth rates of each treatment. Despite our non-significant findings, further research in this field should be pursued for benefiting future green technology.