Fluorescing corals: nature's glow sticks
Joyce Park stashed this in Science
Wow would love to know how glowing helps corals in the middle of the ocean!
Likely explanations: Sunscreen, an indicator of health to attract Spawing, or to ward off predators.
There are several theories provided by scientist, and perhaps the most likely reason is that it acts as a kind of “sun block” for the coral protecting the zooxanthallae inside the coral from the harmful rays of the sun . Marine Biologists say that this property could perhaps protect shallow coral from bleaching or provide deeper coral the ability to absorb the UV light from the sun and reflect it back to the zooxanthallae allowing them to photosynthesize in the absence of sufficient sunlight.
Other fluorescence theories claim that fluorescence is an indicator of the health of coral, or is somehow used to signal coral spawning. Some scientists have also suggested that the light is used by coral to ward off predators.