Do abyssal scavengers use phytodetritus as a food resource? Video and biochemical evidence from the Atlantic and Mediterranean

摘要: Deep-sea benthic communities derive their energetic requirements from overlying surface water production, which is deposited at the seafloor as phytodetritus. Benthic invertebrates are primary consumers of this food source, with deep-sea fish top trophic hierarchy. Recently, we demonstrated use baited cameras that macrourid rapidly respond to and feed vigorously on large plant falls mimicked by spinach (Jeffreys et al., 2010). Since higher remains scarce in deep-sea, exception canyons, where terrestrial material has been observed, these results led us ask if a more commonly documented i.e. phytodetritus might form source for mobile scavenging megafauna. We simulated dump two contrasting environments (1) NE Atlantic carpets have previously observed (2) oligotrophic western Mediterranean, deposition rare occurrence. recorded response fauna using an situ lander equipped time-lapse cameras. In 3000 m, abyssal macrourids cusk-eels were ingesting The phytodetrital patch was significantly diminished within 2 h. Abundance estimates calculated first arrival times corresponded abundance video-transect indicating attracted scent bait. contrast this, Mediterranean 2800 m single investigating but did not it. 6.5 h result mainly invertebrate activity. At 1900 Lepidion lepidion near bait, feed. remained intact until end experiment. deployments corrected body size, lower than obtained video-transects trawl catches. This suggests readily source. contrast, Balearic Sea bait despite occurrence dumps Mediterranean. Stable isotope values both study sites, set context web, demonstrate strong link Fatty acid profiles indicated between lipid pool producers phytoplankton, may be attributed transfer. usefulness fatty biomarkers ascertaining diets discussed. Our grenadier C. armatus Iberian margin However exact contribution diet area unresolved.