Interactive effect of salinity decrease, salinity adaptation, and chlorpyrifos exposure on an estuarine harpacticoid copepod, Mesochra parva, in South Africa

This study tested the hypothesis: “does adaptation to fluctuating salinities lead to enhanced survival of the harpacticoid copepod M. parva when exposed to a combination of particle associated chlorpyrifos (CPF) exposure and hypoosmotic stress during a 96 h sediment toxicity test?” The CPF exposure concentrations of 5.89–5.38 μg/kg and the salinity decrease from 15 to 3 ppt were based on conditions observed in the temporarily open Lourens River estuary, South Africa, in order to simulate changes during a runoff event. Results of the three-factorial ANOVA showed that pre-adaptation to varying salinities ( p=0.02; p=0.001), salinity decrease ( p=0.035; p