Polychaetes of the deep Weddell and Scotia Seas—composition and zoogeographical links

A preliminary analysis of polychaetes from box core samples taken in the Drake Passage, the Weddell Sea, and the Scotia Arc resulted in novel, albeit partial, information about deep-sea communities in the Southern Ocean. Similarities were found with deep-sea fauna worldwide on the generic level and with adjacent basins on species level. Polychaetes, unlike other taxa, apparently have wide geographical ranges. In addition, the well-known phenomenon of eurybathy in the Southern Ocean may have to be reconsidered, as there are indications that the shelf fauna is eventually replaced by deep-sea species, the only difference to temperate oceans being the greater depth of the faunal shift. The general structure of the communities in the deep Southern Ocean resembles that of other deep-sea basins in the low density combined with a high number of species per station.