Dr. Mazel is interested in the phenomenon of coral fluorescence: not just from chlorophyll in symbiotic algae, but also the intense, multi-hued glow from pigments in the animals tissues themselves. How many pigments are there? What are their spectral characteristics? What role do they play in coral physiology? Is the fluorescence an indicator of coral health?
To this end, Dr. Mazel assembled a library of spectral signatures, characterizing the excitation and emission spectra of different corals in vivo and non-destructively. His FLUOROMAX has traveled to ship- and shore-based sites to study fragile corals in the Bahamas and Dry Tortugas.
Dr. Mazel, a scuba-diver, collected specimens and maintained them in a tank of flowing seawater. Through a fiber-optic probe 2 m long, the resultant fluorescence spectra were collected. For the excitation spectra, emission wavelengths of 490, 530, 590, and 690 nm were used, the bandpass = 2 nm, and integration time = 0.2 s; for the emission spectra, excitation wavelengths of 365, 450, and 488 nm were used, the bandpass = 2 nm, and the integration time = 0.5 s.
Results and Conclusions
The research to date indicated that just four autofluorescent pigments contributed to the observed fluorescence from coral. The four pigments fluoresced with peak wavelengths near 486, 515, 575, and 685 nm, respectively (Figures 1 through 4). Chlorophyll (λmax = 685 nm) was found i