Effects of Temperature on Growth Rate of Chlamydomonas reinhardtii


  • Kylie Au
  • Giang Han
  • Ella Kerr
  • Jean-Luc Osborne


Chlamydomonas reinhardtii is a unicellular green algae, and as a primary producer it is
an essential part of our ecosystem, affecting other consumer species such as salmon. Climate
change projections show that the surface temperature of bodies of water are significantly
increasing, and as the water temperature increases, this consequently affects the food chain of
many species. To further explore the effects of temperature, C. reinhardtii was incubated at
20°C, 25°C, and 35°C and sampled over a 14 day period to determine their respective cell
growth. Cell density was counted for each sampled day using a hemocytometer under a
compound microscope. Results showed an increasing linear trend, with 35°C having the largest
cell growth. Furthermore, we determined that the mean cell growth rate at 20°C to be 2.01 x 106
cells/day, 25°C to be 4.11x 106 cells/day, and 35°C to be 6.27 x 106 cells/day. Using a one-way
ANOVA test, it was determined that there was a statistical difference between the means of each
temperature (p=0.0024). Further research testing the effects of climate change using the model
organism C. reinhardtii will provide essential insight on how to help preserve our beautiful