Coral fluorescence characteristics: excitation/emmission spectra, fluorescence efficiences, and contribution to apparent reflectance

The fluorescence characteristic of Caribbean corals have been investigated through in situ and laboratory spectral measurements. Four pigments are the source of most of the observed emissions. In vivo excitation/emission spectra were measured to determine Stokes shift and bandwidth of each of the types. Fluorescence efficiencies for natural fluorescence of the chlorophyll in the zooxanthellae were estimated from 18 in situ measurements, yielding values from 0.15-0.91 percent. Fluorescence efficiencies of the host pigments in 3 strongly fluorescent coral specimens were estimated from shipboard measurements and ranged form 4-6 percent. The quantitative data re being used in a computational model to investigate the contribution of fluorescence to apparent reflectance signatures.