DEEP-SEA HOLOTHURIANS

Holothurians are the dominant epibenthic invertebrate taxon in many areas of the deep sea. Most species feed on the surficial sediment and are therefore important in the initial degradation of organic matter deposited on the sea bed. Through their feeding, faecal production, and locomotion holothurians have an important effect on the rest of the benthic community. This paper reviews work undertaken principally since 1975, the year in which Hansen produced his monograph on the Order Elasipodida. Advances in topics such as feeding, reproduction, locomotion, swimming, and bathymetric distribution, which were reviewed by Hansen, are discussed in addition to abundance, biomass, chemical composition, metabolism, bioluminescence, growth, population structure, and spatial distribution, subjects not treated by Hansen. Recent taxonomic developments are also considered. Apart from reviewing other work, this paper contains new data from a study of the benthic megafauna between the depths of 300 and 4800 m in the northeast Atlantic (The Porcupine Seabight and the Porcupine Abyssal Plain).