Composition, abundance and distribution of Peracarida from the Southern Ocean deep sea

Abstract

Abstract Peracarida are an important component of both the deep-sea fauna and the fauna known from the Antarctic shelf. The peracarid composition from epibenthic-sledge samples obtained during the expeditions ANDEEP I–III is shown and compared to that of other deep-sea basins and the Antarctic shelf. The Amphipoda were the most abundant taxon in the samples, with 43% of all peracarid individuals, followed by the Isopoda (35%), Cumacea (16%), Tanaidacea (5%) and Mysidacea (1%). Highest abundances were found at the shallower stations, but a clear trend towards decreasing abundances with depth could not be confirmed. Although the decrease of amphipod numbers and the increase of isopod numbers with depth in general correspond to other areas, e.g., the Angola Basin, the Southern Ocean deep sea seems to be special by harboring more amphipod specimens at medium depths, thus reflecting the situation on the Antarctic shelf. Outstanding by their number of specimens were the samples from station 133-2 at about 1500 m depth in the Powell Basin, which contained the highest number of specimens, and from station 152-6 in the Bransfield Strait, where the number of specimens was strikingly low despite the moderate depth of about 2000 m.