(Georgia Institute of Technology, 2004-07-14)
Kicklighter, Cynthia Ellen; Fisher, C. R.; Hay, Mark E.
Organisms at deep-sea hydrothermal vent or cold-seep communities represent oases of
prey in an otherwise prey-poor desert. Why deep-sea consumers that remove other dense food
patches do not rapidly remove the high biomass of prey from these communities is unclear. One
potential explanation is that hydrogen sulfide, or other metabolites, in these chemoautotrophic prey
could be serving as chemical defenses against generalist consumers; however, neither the palatability
of these prey nor their potential defenses have been assessed. We fed tissues from 10 species of
deep-sea polychaetes and 2 species of bivalves to shallow-water fishes Fundulus heteroclitus and
Leiostomus xanthurus or crabs Callinectes similis and Pachygrapsus crassipes to assess their palatability
to generalist consumers. Tissues from 4 polychaetes (Archinome rosacea, Lamellibrachia luymesi,
Riftia pachyptila, and Seepiophila jonesi) and 1 bivalve (Calyptogena magnifica) were rejected
by some consumers. Blood, which can be sulfide-rich, from R. pachyptila did not deter feeding. Sharp
setae deterred feeding on the polychaete A. rosacea, while the other unpalatable species produced
chemical extracts that deterred feeding. All of the chemically deterrent species contained chemoautotrophic
endosymbiotic bacteria, suggesting that these microbial symbionts may produce metabolites
that defend their host species. In several instances, consumers encountering novel, deep-sea
prey consumed more on the first day of feeding than on later dates, or initially rejected the foods, but
then consumed them after repeated encounters. Investigations with predators from the deep-sea are
required to more fully understand the ecological role of prey defenses for deep-sea species.