Colonies of the bioluminescent marine bacterium Vibrio fischeri.

Colonies of the bioluminescent marine bacterium Vibrio fischeri. The photograph of colonies growing on agar (left) was taken with a light source. The photograph of colonies on the right was taken using their own bioluminescence as a light source. [One of four related images. See Next Image.]

National Science Foundation-supported researchers are studying the relationship between the Hawaiian sepiolid squid Euprymna scolopes, and its luminous bacterial partner Vibrio fischeri. Although all animals have beneficial associations with microbes, the association between Euprymna scolopes and Vibrio fischeri is the only experimental model available to biologists so far. (Year of image: 1975)