This weeks photo is from Phil Hart, it is one of the most popular photos seen online when talking about bioluminescence and was taken at the Gippsland Lakes Gippsland, Victoria, Australia.
Bioluminescence is the term for the light produced by a living organism. The bioluminescence seen in this photo is caused by marine-dwelling species of dinoflagellate Noctiluca scintillans. It uses an oxidative enzyme in the luciferase family to produce the glow. A similar luciferase is used in other bioluminescence species such as fireflies, a few beetles, some bacteria, as well as other dinoflagellates.
The function of bioluminescence in dinoflagellates has been hypothesized to be a form of communication between each other. Early work suggested it might serve as a warning system of sheer forces of near by preditors, more recent work suggests it might play a role in maintaining and synchronizing circadian rhythm (internal cell clock, for keeping track of cell cycle).