Many deep-sea shrimp glow but researchers have found the light organs in deep-sea shrimp may have evolved depending on depth and habitat.
FIU marine scientist Heather Bracken-Grissom and her graduate student Charles Golightly collaborated with a team of researchers to trace the evolutionary history of a family of deep-sea shrimp, the Sergestidae.
The shrimps' light organs, called photophores, vary in size, quantity and structure and some seem to be correlated with the habitat and depth at which they reside and vertically migrate within the water column. This research also revealed that the species that live in the deepest waters have evolved to have no photophores at all. This research begins to shine a light on how photophores have evolved, but many questions still remain.
"We have this one family of deep-sea shrimp, but they all have remarkable and unique variations of light organs. But why?," Bracken-Grissom said. "We wanted to understand why there was so much diversity. It was very cool to see that the organs might actually be adapted to the depth at which they are living, as well as the habitat."
Scientists believe the photophores play an important role in camouflage, helping the shrimp hide. As shrimp migrate to shallow waters, where downwelling light is present, the photophores turn on to mimic the light and help the shrimp camouflage themselves from predators. Recent evidence has also suggested these photophores may detect light.
The deep-sea shrimp from the Sergestidae family has three different variations of photophores — lensed, non-lensed and internal light organs called organs of Pesta.
