Ward's® Agriculture and the Environment LC50: How Much is Too Much Nitrate? Lab Activity

Exciting Environmental Chemistry

• Students Observe the Effects of a Chemical on an Organisms in Real Time
• Cross-Discipline between biology, chemistry and environmental science

Become part of a scientific team assigned to conduct a bioassay demonstrating the effects of ammonium nitrate on Daphnia magna. Using a fluorescently-tagged sugar, you will examine the effects of ingestion of different concentrations of ammonium nitrate by the Daphnia. The investigation will allow students to determine which Daphnia are healthy and which are adversely affected by exposure to ammonium nitrate. After a healthy Daphnia eats the specially tagged sugar, the fluorometric marker is cleaved from the sugar during digestion and circulates throughout the organism's system. This animal will fluoresce under long wave ultraviolet light. The adversely affected Daphnia will be unable to ingest or digest the sugar, and as a result will emit little or no light. The goal of the bioassay is to determine the LC50 value of ammonium nitrate within the Daphnia.

Included:
Medicine cups
Disposable pipets
Clear plastic trays
Plastic vials and caps
Plastic cups
Graph paper
Ammonium Nitrate
Plastic spoon
Spray bottle
Medium sand
Clear plastic container
Food coloring

Required but not Included: UV Light (Black light), UV Protective Goggles, Beaker or small container, distilled water, scissors, markers, disposable lab gloves, safety goggles, graduated cylinders, paper towels, object to elevate container, and datalogger/conductivity probe (optional).

In order to ensure that you have the freshest materials to complete this activity, please be sure to order the following prior to performing this activity: 470180-306: Daphnia magna, Mixed Sizes and 470184-484: MUG Vial.