Unmixing coral fluorescence emission spectra and predicting new spectra under different excitation conditions

An algorithm was developed that uses prototype spectra and least-squares minimization to unmix the relative contributions of individual pigments to the composite fluorescence emission spectrum of reef corals. Field measurements indicated that it was necessary to include allowance for spectral shift of the wavelength peak of the prototype emission spectra. The unmixed spectra are used to predict the shape and amplitude of composite spectra that would be expected under different excitation conditions. We found that, for cases in which the pigments occur singly or with significant spectral separation, it is necessary to consider the properties of the excitation light sources, only, to make accurate predictions. In cases with spectral overlap the contribution of interpigment coupling cannot be neglected. (C) 1999 Optical Society of America.