NOAA Ocean Explorer: Bioluminescence 2009:  Living Light on the Deep-sea Floor.  TM Frank, Expedition Chief Scientist.

We know that a wide variety of deep-sea animals that live in the water column produce light (bioluminescence), but information on light production by those that live on the deep-sea floor is sparse. On an expedition to the Bahamas in 2009 funded by NOAA’s Office of Ocean Exploration, we used the Johnson-Sea-Link submersible, its array of specialized collecting tools, and very low-light-sensitive color cameras to explore bioluminescence and vision on the deep-sea floor. The expedition verified ultraviolet-sensitive vision in two deep-sea crabs (Gastroptychus spinifer and Eumunida picta) and revealed that planktonic animals emit light when they drift into and strike tall corals and sea pens on the seafloor. Although bioluminescence proved rare in seafloor creatures compared to those in the water column, they turned out to produce a wider range of colors (including green to almost yellow light). Results suggest that the unusual dual visual pigments in some deep-sea crabs may permit them to distinguish planktonic prey from their seafloor habitat.