title: Rapid scavenging of jellyfish carcasses reveals the importance of gelatinous material to deep-sea food webs.
abstract: Jellyfish blooms are common in many oceans, and anthropogenic changes appear to have increased their magnitude in some regions. Although mass falls of jellyfish carcasses have been observed recently at the deep seafloor, the dense necrophage aggregations and rapid consumption rates typical for vertebrate carrion have not been documented. This has led to a paradigm of limited energy transfer to higher trophic levels at jelly falls relative to vertebrate organic falls. We show from baited camera deployments in the Norwegian deep sea that dense aggregations of deep-sea scavengers (more than 1000 animals at peak densities) can rapidly form at jellyfish baits and consume entire jellyfish carcasses in 2.5 h. We also show that scavenging rates on jellyfish are not significantly different from fish carrion of similar mass, and reveal that scavenging communities typical for the NE Atlantic bathyal zone, including the Atlantic hagfish, galatheid crabs, decapod shrimp and lyssianasid amphipods, consume both types of carcasses. These rapid jellyfish carrion consumption rates suggest that the contribution of gelatinous material to organic fluxes may be seriously underestimated in some regions, because jelly falls may disappear much more rapidly than previously thought. Our results also demonstrate that the energy contained in gelatinous carrion can be efficiently incorporated into large numbers of deep-sea scavengers and food webs, lessening the expected impacts (e.g. smothering of the seafloor) of enhanced jellyfish production on deep-sea ecosystems and pelagic-benthic coupling.
authors.affiliation: International Research Institute of Stavanger, Mekjarvik 12, Randaberg 4070, Norway andrew.sweetman@iris.no.
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Sweetman
authors.affiliation: University of Hawaii at Manoa, 1000 Pope Road, Honolulu, HI 96822, USA.
authors.forename: Craig R
authors.initials: CR
authors.lastname: Smith
authors.affiliation: Norwegian Institute for Water Research (NIVA), Thormøhlensgate 53D, Bergen 5006, Norway.
authors.forename: Trine
authors.initials: T
authors.lastname: Dale
authors.affiliation: National Oceanography Center, University of Southampton Waterfront Campus, European Way, Southampton SO14 3ZH, UK.
authors.forename: Daniel O B
authors.identifier: 0000-0001-5218-1649
authors.initials: DO
authors.lastname: Jones
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D003445:Crustacea / Q000502:physiology; D017753:Ecosystem; D004734:Energy Metabolism; D005247:Feeding Behavior; D005399:Fishes / Q000502:physiology; D020387:Food Chain; D005780:Gelatin; D037401:Scyphozoa / Q000502:physiology*; D012621:Seasons
chemical_list: D005780:Gelatin
keywords: biological pump; deep sea; jellyfish carcasses; metazoans; scavenging