Daphnia Toxicology Experiment

Bridges 2014

DaphniaFreshwater planktonic crustaceansCyclic parthenogenesis

Favorable conditions: Asexual reproduction of femalesUnfavorable conditions: Sexual reproduction

Reproductive maturity: 3-5 daysFine mesh feeders

Eat bacteria and algaeSwim with an erratic, jerking motion then hang

motionless in the waterMany predators, including fish, shrimp and copepods

ToxicityThe degree to which a substance can damage

an organism or the environmentToxicity is dose dependent

Too much water can be deadlyJust a little snake venom can be deadly

Many household products are toxicThis is an issue when they enter the

environment or our drinking water!

Examples Household ToxinsDrain cleaners Oven cleanersLaundry detergentsFloor or furniture polishPaints PesticidesDisinfectantsCleaning ProductsMany others…

Testing Toxicity with DaphniaPick a substance that you think will be toxic

to DaphniaCreate serial dilution of substance

Think carefully about what dilutions to useShould include:

Positive control (will kill) Negative control (won’t kill)

Transfer live Daphnia to plate containing dilution of potentially toxic substance

Score dead/live Daphnia in each treatment daily