Fig. 7.

Time course of photosynthesis and pH in N. salina. a Net photosynthetic O₂ production and net CO₂ uptake. b Effective quantum yield measured via variable chlorophyll fluorescence in the light. c pH shown here to highlight that the decrease in discrimination after 4 h of exposure to low CO₂ was correlated with an increasing pH in cultures that were stable at high CO₂ prior to switching. Error bars represent the SE of the mean, n = 3