1. 1. Direct response of 6 common Antarctic zooplankters (the euphausiid Euphausia superba, the copepods Calanoides acutus and Euchaeta antarctica, the amphipods Parathemisto gaudichaudii and Hyperiella antarctica, and the polychaete Tomopteris carpenteri) to temperature changes was measured and their temperature tolerance tested. 2. 2. Respiration rates followed the Arrhenius equation in the range examined (generally - 1 to + 10°C). 3. 3. Temperature coefficients varied between 8.06 and 23.84, while Q10 values from 1.64 to 5.24 were found. 4. 4. When krill data were compared with experiments on North Sea Meganyctiphanes norvegica, no significant difference was found for Arrhenius coefficients. 5. 5. No mortality occurred within 30 hr at temperatures from - 1 to 10°C. 6. 6. The results are discussed with regard to the concept of metabolic cold adaptation. © 1984.