Abstract: Research on the patterns of the vertical distribution of zooplankton could help improve understanding of the role of zooplankton in the marine food web. Based on samples collected in the South Shetland Islands during the 28th Chinese National Antarctic Research Expedition, vertical profiles of the zooplankton community structure were investigated using multivariate analysis and three communities identified. Group 1 contained samples collected in surface water (0–200 m). The average abundance of this group was 31 782.02 ind·1 000 m^-3 and the indicator species were mostly copepods: Oithona similis, Ctenocalanus citer, Oncaea curvata, Calanoides acutus, Calanus propinquus,and Calyptopis I-III stages of Euphausia superba. Group 2 comprised samples from depths of 200–1 000 m. The average abundance was 22 325.59 ind·1 000 m^-3 and the indicator species were mostly O. curvata, O. similis, Oithona frigida, C. citer, Aetideopsis minor, Bathycalanus bradyi, C. acutus, C. propinquus, Metridia gerlachei, Alacia spp., and Eukrohnia hamate. Group 3 comprised samples collected in deep water (1 000–2 000 m). The average abundance was only 989.27 ind·1 000 m^-3 and the indicator species was Bathycalanus bradyi. Bio-Env analysis showed that chlorophyll a and salinity were the most significant factors affecting community structure and that consideration of these two factors with depth provided the best explanation for the community clustering.

Key words: zooplankton, community structure, copepod, krill, South Shetland Islands, Antarctica