Bioluminescence 2009: Living Light on the Deep-Sea Floor

Studies on bioluminescence in deep-sea pelagic animals are extensive, but information on bioluminescence in the deep-sea benthos is sparse, due to the difficulty in getting live animals in trawls and dredges. On a NOAA Office of Ocean Exploration-funded expedition to the Bahamas in 2009, 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. Studies conducted on this expedition verified UV vision in a deep-sea chirostylid crab ( Gastroptychus spinifer , Anomura, Galatheoidea), discovered UV sensitivity in another species ( Eumunida picta ), produced an array of remarkable images (both in situ and in the laboratory) of the bioluminescence of various animals, and revealed that benthic bioluminescence is fairly rare compared to planktonic bioluminescence. Based on 1) in situ observations that substantial bioluminescence is produced by planktonic animals when stimulated to glow by striking tall benthic corals and sea pens , and 2) benthic species produce a wider range of colors (including green to almost yellow light) than open ocean zooplankton, we suggest that the unusual dual visual pigments in some deep-sea crab species may permit them to distinguish planktonic prey from benthic habitat.