Figure 4. Relationship between green fluorescence and coral tissue surface heating.

Coral tissue surface heating is expressed as ΔT (°C), i.e., the difference between coral surface temperature and the temperature in the ambient water, and was integrated for excitation between 400–700 nm (PAR) and expressed for a total irradiance delivery of 500 W m⁻². FP fluorescence (a.u.) was normalized to the maximally measured fluorescence (=1). The black line shows the positive correlation between heating and green fluorescence (R² = 0.89). Dashed lines are 95% confidence intervals.