ABSTRACT

The Southern Ocean comprises all waters south of the Polar Front (referred to as the Antarctic Convergence in the earlier literature). This well-defined circum-Antarctic oceanographic feature marks the northernmost extent of cold surface water. The total area of the Southern Ocean is thus about 34.8millionkm2. Of this, up to 21millionkm22 is covered by ice at the winter maximum but only about 7millionkm2 is covered at the summer minimum (Gloersen et al. 1992). Two influential schemes for subdividing this vast area of ocean are those of Tréguer & Jacques (1992) based predominantly on ice and nutrient dynamics, and Longhurst (1998) based on upper water column structure and remotely-sensed phytoplankton pigments. These schemes are based essentially on surface processes but they are relevant to the benthos in that almost all life on the sea bed depends on the flux of material from surface waters for its energy and nutrients. Patterns of surface production will therefore influence the diversity, abundance and ecology of benthic organisms, albeit modified by advective processes.