Daylight and fluorescent images of a Montastrea caverno

Daylight and fluorescent images of a Montastrea cavernosa coral colony growing on the seawall at Ft. Jefferson, Dry Tortugas National Park. The brownish color of the coral in daylight is largely attributable to chlorophyll contained within the symbiotic algae harbored by the coral. The fluorescent image was taken at night using blue LED lights to stimulate fluorescence. The green color is attributable to a compound called green fluorescent protein (GFP) contained in the coral tissue, not the symbiotic algae.