Acute acidic stress from sources such as acid rain might impact on lake ecosystems in many aspects. Because zooplankton is sensitive to environmental change, it could be a good biotic indicator of the effects of acidification. We investigated survival and metabolic rates of three dominant zooplankton taxa in Lake Biwa, the cladoceran Daphnia pulicaria, and the copepods Eodiaptomus japonicus and Cyclopoida spp., when subjected to different pH values (pH 4.0−8.0) at low (10 °C) and...