Light and vision in the deep-sea benthos: I. Bioluminescence at 500–1000 m depth in the Bahamian Islands

Abstract

SUMMARYBioluminescence is common and well studied in mesopelagic species. However, the extent of bioluminescence in benthic sites of similar depths is far less studied, although the relatively large eyes of benthic fish, crustaceans and cephalopods at bathyal depths suggest the presence of significant biogenic light. Using the Johnson-Sea-Link submersible, we collected numerous species of cnidarians, echinoderms, crustaceans, cephalopods and sponges, as well as one annelid from three sites in the northern Bahamas (500-1000m depth). Using mechanical and chemical stimulation, we tested the collected species for light emission, and photographed and measured the spectra of the emitted light. In addition, in situ intensified video and still photos were taken of different benthic habitats. Surprisingly, bioluminescence in benthic animals at these sites was far less common than in mesopelagic animals from similar depths, with less than 20% of the collected species emitting light. Bioluminescent taxa comprised two species of anemone (Actinaria), a new genus and species of flabellate Parazoanthidae (formerly Gerardia sp.) (Zoanthidea), three sea pens (Pennatulacea), three bamboo corals (Alcyonacea), the chrysogorgiid coral Chrysogorgia desbonni (Alcyonacea), the caridean shrimp Parapandalus sp. and Heterocarpus ensifer (Decapoda), two holothuroids (Elasipodida and Aspidochirota) and the ophiuroid Ophiochiton ternispinus (Ophiurida). Except for the ophiuroid and the two shrimp, which emitted blue light (peak wavelengths 470 and 455nm), all the species produced greener light than that measured in most mesopelagic taxa, with the emissions of the pennatulaceans being strongly shifted towards longer wavelengths. In situ observations suggested that bioluminescence associated with these sites was due primarily to light emitted by bioluminescent planktonic species as they struck filter feeders that extended into the water column. Supplementary material available online at

Deep-sea anemone (Cnidaria: Actiniaria) exhibits a positive behavioural response to blue light

“…A more likely light source may be bioluminescence. Recent studies have observed deep-sea plankton generating light from frequent collisions with physical or biological structures on the seafloor, suggesting greater frequency of bioluminescence than in the upper water column (Craig et al 2011;Johnsen et al 2012). In this case the bending behaviour would be helpful in orienting the anemone towards the source of bioluminescence.…”

Light and vision in the deep-sea benthos: II. Vision in deep-sea crustaceans

“…Although the number of benthic bioluminescent species is relatively rare in the location occupied by many of the crustaceans in this study (Johnsen et al, 2012), evidence suggesting that at least two species of deep-sea anomuran crabs possess both UV-and bluesensitive visual pigments indicates that bioluminescence still may have been a driving force behind their visual adaptations. Further studies are needed to determine whether UV sensitivity is common in the deep-sea Chirostyloidea, the superfamily to which E. picta and G. spinifer belong, as well as other deep-sea 'stalk sitters'.…”

“… max of 473.8±2.9nm for medusae (N34), 486.1±1.6nm for ctenophores (N41), and two modes for siphonophores, centered at 450.5±1.3nm (N16) and 486±2.3nm (N9) (Haddock and Case, 1999). Lophelia pertusa is not bioluminescent (Johnsen et al, 2012), but would still provide a raised substrate for the plankton to impact against, and a dual visual pigment system may help enhance contrast between the bioluminescence and the remaining bluish downwelling light as well.…”

“…However, at the Little Bahamas Bank Lithoherms, both species of crabs were frequently seen on pennatulaceans (sea whips) or zoanthids (colonial anemones known as gold corals) (Fig.5A,B), both of which emit a greenish bioluminescence (Johnsen et al, 2012). In a remarkable long exposure image taken by S.J.…”

Insights into the Biodiversity, Behavior, and Bioluminescence of Deep-Sea Organisms Using Molecular and Maritime Technology

“…For many deep-sea organisms, this remarkable capability was discovered for the first time by our labs when examining the live-caught specimens. For example, we have documented bioluminescence for the first time in polychaetes (Swima, Osborn et al, 2009;Chaetopterus pugaporcinus, Osborn et al, 2007;Poeobius, Haddock et al, 2010;Francis et al, 2016b), doliolids (Paradoliopsis, Pseudusa, Doliolula; Haddock et al, 2010), chaetognaths (Caecosagitta macrocephala and Eukrohnia fowleri, Haddock and Case, 1994;Thuesen et al, 2010), gastropods (two yet undescribed species), and sea anemones (Hormathiidae, Haddock et al, 2010;Johnsen et al, 2012). Bioluminescence was not known to occur in four of these taxonomic lineages before our observations.…”