Figure 10: Typical graph of photosynthetic O2 concentration (partial pressure) versus time. Each unit in X-axis was set to be 1 min. After several minutes when the recorder system was on, the light was turned on to trigger the algal photosynthetic activity, and the oxygen concentration started to increase. After several minutes, the light was turned off to observe the oxygen consumption (net respiration). The total photosynthetic oxygen generation rate was then alculated assuming that the rate of respiration in the light was the same as the respiration measured in the dark (see Appendix 1).