Incorporating Daphnia magna into the seven-day Ceriodaphnia effluent toxicity test method

The experiments reported here describe the incorporation of Daphnia magna into the 7-d Ceriodaphnia toxicity test procedure of Mount and Norberg [1]. The addition of D. magna to the procedure increased the number of parameters on which decisions regarding sublethal effects could be determined without significantly increasing the workload. In addition to the survival and productivity measures of the Mount and Norberg procedure, length and weight of Ceriodaphnia dubia adults and D. magna adults and neonates were evaluated. Methods for the culture and testing of both organisms using Selenastrum capricornutum Printz as the food source were described. An analysis of algal caloric content, chlorophyll a, cell number, mean cell volume, dry weight, number of bacteria, storage time, and time since the algae were “cleaned” was made to determine the characteristics of the feeding suspensions which most influenced the growth and productivity of the cladocerans.