Scientists from the University of Sydney and the University of Copenhagen in Denmark have discovered that the fluorescent pigments in some corals protect them against sunlight and may help them survive the mass episodes of coral bleaching associated with global climate change.
Corals depend on a symbiotic relationship with dinoflagellate algae.
They give the algae a home, and the algae reciprocate by providing nutrients. Stripped of their dinoflagellate roommates, the corals die. They also compared how well the fluorescent and nonfluorescent varieties of the same species can tolerate intense light. Some fluorescent corals house the pigments in layers above the dinoflagellates, where they can absorb excessive sunlight before it damages the symbionts, explained Sydney's Anya Salih, a postdoctoral fellow on the team. Once intercepted, the ultraviolet and blue light is converted through a fluorescence energy transfer chain to yellow and red wavelengths, which are less dangerous because they are not absorbed by the dinoflagellates' photosynthetic apparatuses.