Did you know that some corals bioluminesce? Neither did we. This video was made by a deepsea submersible off the coast of Florida and believe it or not, this video was made in complete darkness. The light which is visible on the surface of the coral is the result of the manipulator arm of the deep sea sub stroking the coral and triggering the biological light reactions. The mechanisms of bioluminescence in corals are undocumented but if it is anything like many other animals which bioluminesce in the sea and on the land, it’s likely the result of a symbiotic relationship with bacteria which cause the glow.