Measuring the Effect of Decreasing Light Intensity on the Cell Density of the Unicellular Algae Chlamydomonas reinhardtii at 17⁰C

Abstract

The purpose of conducting the experiment was to find the optimal light intensity range for growth of the unicellular, photosynthetic algae, Chlamydomonas reinhardtii. Since the rate of photosynthesis is dependent on light intensity and availability, light directly impacts the growth of C. reinhardtii. Over a period of 10 days, we counted cell density of C. reinhardtii exposed to four different light intensities: 8020 Lux (control), 5700 Lux, 3180 Lux and 0 Lux. We found that there was no statistical significance between the control group and the 5700 and 3180 Lux groups. We suggest that clumping of the algae observed after 144 hours is the reason behind the largely variant cell densities. It is also possible that we grew C. reinhardtii at a lower than optimal temperature, giving similar cell densities in the control group and 5700 Lux and 3180 Lux groups. Through our results and observations, we are unable to reject our null hypothesis.