Deposit feeding by some deep-sea megabenthos from the Venezuela Basin. selective or non-selective

Food sources and feed~ng selectiv~ty of numerically dominant asteroids and holothurians collected with trawls from the Venezuela Basin, Caribbean Sea, were investigated by means of gut analysis.Particle-size distributions of gut contents of 73oracaster cylindratus, Styracaster hom'dus, Psychropotes semperiana, and Pseudostichopus atlanticus and of sediments were compared from 3 different sedimentary provinces in the Venezuela Basin (3.410-5.062m depth).Megabenthic echinoderms (megabenthos) from the 2 shallower provinces had gut contents with particle-size distributions almost identical to that of the top 5 mm of sediment and conspicuously coarser than sediment below 5 mm depth.Gut contents of echinoderms from the deepest province had a higher percent of coarse and medium sand-size foraminiferan tests than that of surrounding sediment.Microscopic examination of the coarse fractions revealed intact pelagic foraminiferan tests in the guts of megabenthos collected from 5,000 m depth whereas pelagic foraminiferan tests from surrounding surface sediments were fragmented and eroded.The possibility of recently settled fecal pellets from the pelagic realm as a food source is suggested.These data suggest that some bulk deposit feeders skim the surface of the sea bottom feeding on the uppermost layer of sediment; thus, they selectively ingest the more nutritive, uppermost layer of sediment in the deep sea without modifying feeding behavior perse.