Copepod Communities in the Pacific Sector of the Southern Ocean in Early Summer

摘要: Copepod composition, distribution, abundance and biomass were investigated in offshore waters of the South Pacific at beginning Antarctic summer, during Italian expedition 1989–90 with RV Cariboo. The stations scattered a vast area extending from 62° to 73°S, within longitudinal limits 161°E 177°W. Zooplankton samples collected different depth an EZ-BIONESS-NET fitted 500-µm mesh opening-closing nets. Depending on hydrology ice-cover conditions, four zones considered study north south, i.e. near polar front, pack ice, drifting ice ice-free. In all areas except pack-ice zone, bulk copepods occurred close surface. first 100 m, assemblages mainly consisted adult females M. gerlachei C. acutus already clustered surface, ready for spawning. On however, ascent surface had not yet begun or was less pronounced. greater concentration found upper m southernmost area, one that been ice-free longer. Below copepod numbers abruptly diminished diversity notably increased. Recorded oceanic greatly vary 200 ranging 0.02 2.3g DW/m2. It varied range 0.04–1.2g DW/m2 1000 m. noticed sampling methods may constitute significant source variability determining zooplankton standing stocks. present highest concentrations detected only analyzing euphotic layer (0–200 m) divided 20-m-thick sections, while they went undetected same 100-m-thick sections.