The Effect of Light Intensity on Oxygen Production of Euglena gracilis


  • Emad Basiri
  • Jinny Jang
  • Christina Kim
  • Ellena Yoon


This study aims to investigate the effect of increasing light intensity on the oxygen production by Euglena gracilis. E. gracilis serves as an essential source of oxygen for salmon species to uptake, which then can be used to perform various life functions such as growth, digestion, and locomotion. Light intensity promotes vertical movement of E. gracilis to stay in regions where optimal photosynthesis can occur, leading to the prediction that oxygen production of E. gracilis will increase with increasing light exposure. To test this prediction, we exposed the E. gracilis to three different light intensities (20Wm-2, 35Wm-2, 50Wm-2) and measured the oxygen concentration at the 0hr, 3hr, and 6hr mark. We also counted the number of cells at each stage in order to measure the O2 production rate per cell. Our one-way ANOVA results showed an overall decreasing trend in the oxygen production per cell across all three different light intensities. Statistical analysis also showed no relationship between the two variables under investigation. As a result, we failed to reject the null hypothesis. This may have been caused by human errors during the course of the experiment, including gas exchange as a possible confounding variable.