| Summary: | Chlorophyll a, primary productivity and grazing by copepods on phytoplankton were measured in the upper water column during the summer of 1994/1995 at a coastal site near Davis Station, East Antarctica. Chlorophyll a was at a maximum in mid-December, then dropped markedly as the coastal fast ice melted and broke-out. Phytoplankton biomass increased again from mid- to late-February. Copepods accounted for at least 65% of zooplankton biomass in the water column before sea ice break-out, whereas larval polychaetes and ctenophores dominated after ice break-out. Oncaea curvata was the numerically dominant species throughout the study. The highest grazing rate (8.7 mg C m-3 d-1) was recorded on 21 December when O. curvata accounted for 64% of the total. Grazing had decreased markedly by 28 December (0.9 mg C m-3 d-1); again O. curvata accounted for over 50% of the total ingested. Copepod grazing increased after ice break-out until the last experiment on 20 February (≃5 mg C m-3 d-1). The main species responsible for grazing during this period were O. curvata, Oithona similis, Calanoides acutus and unidentified copepod nauplii. It was estimated that copepods removed between 1 and 5% of primary productivity.
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