Offspring performance of Daphnia magna after short-term maternal exposure to mixtures of microcystin and ammonia.

During degradation of cyanobacterial blooms, some derived pollutants are released to the waters and last for a while before returning to normal levels. To assess whether the offspring of exposed Daphnia was affected by their maternal experience, we exposed mother Daphnia magna to mixtures of unionized ammonia (0, 0.30, and 0.48 mg L(-1)) and microcystin-LR (0, 10, 30, and 100 μg L(-1)) for 10 days and then immediately moved their offspring to a toxicant-free environment. The offspring were cultured for 21 days to record their survival, development, and reproduction. Results showed that the survival of the offspring of D. magna that experienced high doses of mixed toxicants decreased significantly, but there was no significant difference in development among the survivors of the offspring from different maternal treatments. However, reproductive performances significantly differed among the offspring from different maternal treatments, indicating that there existed a maternal effect in the offspring of D. magna that experienced high levels of mixed toxicants.