The effect of temperature on the growth rate of Chlamydomonas reinhardtii

  • Lindsey Belsher
  • Brian Cheng
  • Claire Choi
  • Jenny Tang


         The green flagellate algae, Chlamydomonas reinhardtii, a primary producer in the aquatic ecosystem, is an important food source for salmon. Due to global warming, the change of water temperature may have strong impacts on many species’ growth in the ocean. Therefore, this study investigated the effect of temperature on the growth rate of C. reinhardtii. It was predicted that a change in temperature would result in change in the growth rate of C. reinhardtii. In this experiment, C. reinhardtii was grown at 11°C, 20°C or 30°C. Time dependent cell densities were determined by counting cells in hemocytometers under a compound microscope over a period of 11 days. Growth rates and subsequently maximum instantaneous growth rates were determined. Results show that C. reinhardtii has the highest maximum growth rate at 11°C, followed by 20°C, and 30°C. Based on the result of a 1-way ANOVA test, there was no significant difference between 11°C and 20°C. However, significant differences were found between 30°C and the other two temperatures. Therefore, we concluded that temperature change would have an impact on the growth rate of C. reinhardtii. Further research can be focused on investigating factors other than temperature that impact the optimal growth condition for C. reinhardtii such as salinity and light intensity.