Published online by Cambridge University Press: 11 May 2009
INTRODUCTION
In the deep oceans where the water depths are in excess of 4000 m the benthic environment is widely separated from the productive euphotic zone and there is an exponential decline in pelagic biomass with increasing depth (Vinogradov, 1968; Wishner, 1980; Angel & Baker, 1982). The sea-bed acts as a sediment trap stopping the downward drift of particulates. Here resuspension and biological and geochemical processes in the benthic boundary layer cause enrichment of the waters above the sediments. Wishner (1980) has noted some of the evidence for near-bottom increases in phosphorus, nitrogen, ATP and sediment resuspension in the deep sea. In parallel with this enrichment and probably related to it, the pelagic macroplankton biomass is increased, at least to distances up to 100 m off bottom (Wishner, 1980; Angel & Baker, 1982). This suprabenthic zone seems to be inhabited by a distinct community of nektonic and planktonic species quite different to that inhabiting comparable depths in the abyssopelagic zone. Marshall & Merrett (1977) reviewed what was known of this community, with special reference to the fishes. Grice & Hulsemann (1970) and Grice (1972) have described new suprabenthic copepod species and Angel & Baker (1982) recorded an entirely novel pelagic ostracod fauna of 25 new species in a 5–20 m off bottom haul at 20°N, 21°W in 4005 m of water.