Effect of varying pH adjusted media on the growth rate of Chlamydomonas reinhardtii

Abstract

Changes in the pH of marine environments can have a major impact on the growth and survival of primary producers. Since the marine food chain is largely comprised of algae, and changes in lower trophic levels can cascade throughout higher trophic levels, it is important to enhance our understanding of how variations in pH affect algal growth. The objective of our study was to investigate the direct effect of pH on the growth rate of Chlamydomonas reinhardtii at pH 5, 6.7, and 8. C. reinhardtii was exposed to pH adjusted media over a set period of time and periodic cell counts were conducted using a hemocytometer and Zeiss Axiostar compound microscope. A one-way ANOVA test was used for statistical analysis, which depicted that growth rate was highest at the optimal pH of 6.7, lower at pH 8 and lowest at pH 5. The calculated p-value of 0.00036 (p<0.01) indicates that pH has an effect on growth rate of C. reinhardtii, as growth decreased significantly when exposed to pH conditions which deviated away from pH 6.7. Our findings suggest that environmental pH is a critical factor in achieving optimal growth for C. reinhardtii.