Fig. 3 Light induction recovery curves for effective quantum yield of photosystem II and NPQ for Symbiodinium within colonies of the reef-building coral Acropora aspera recorded at 18:00 h. (A) Amount of photosynthetically active radiation (PAR) that the coral branches were exposed to throughout the light induction recovery curve. (B) Effective quantum yield measurements for day 18. (C) The actinic light period showing the gradual saturation of photosystem II. (D) NPQ measurements for day 18. Corals preheated 2 weeks prior- (H²; filled circles), 1 week prior (H¹; filled triangles), and not preheated (H⁰: open diamonds) were then subjected to a simulated bleaching event (control; open squares). Error bars shown, but not always visible, represent ± s.e.m., N=10. ^*Significant difference (post-hoc LSD analysis, P<0.05) between treatment and control on the same day; significant difference (post-hoc, LSD, P<0.05) between treatments on the same day.