Biomagnification Activity

This Pesticide Education demonstration introduces biomagnification – when organisms accumulate chemical residues from organisms they eat in the food chain.
Biomagnification Activity - Articles

Learning Objective:

Introduce biomagnification - when organisms accumulate chemical residues from the organisms they are eating underneath them in the food chain.

Suggested Audience:

High school students, adults, and anyone learning about pest management and pesticide safety.

Suggested Time:

Activity can be facilitated in 10 - 15 minutes.

Pennsylvania Academic Standards:

  • Environment and Ecology 4.1.10.E Analyze how humans influence the pattern of natural changes in ecosystems over time.
  • Environment and Ecology 4.5.12.B. Evaluate pest management methods such as cost/benefit analysis, cumulative effects analysis, environmental impact analysis, ethical analysis, and risk analysis.

Materials Needed:

  • Paper
  • Marker
  • Scissors

Prep Work:

Cut 20 pieces of paper to 2" x 2" in size. Using the marker, write "B" on 1 piece, write "F" on 3 pieces, and write "Z" on 6 pieces. Write "A" on the remaining 10 pieces; underneath the "A" write ".5" on each piece.

The letters represent parts of the food chain- bird, fish, zooplankton, and algae. The ".5" represents the chemical concentration in the planktonic algae from the contaminated water. Ensure there is enough space on the "B," "F," and "Z" cards for participants to tally the chemical concentrations or draw a line underneath the letter for the chemical concentration total. If desired, could scale the pieces of paper to be similar to the creatures, such as a larger piece for the bird and smaller pieces for the planktonic algae.

Please note the number of materials will depend on the number of participants in this activity. If you have less participants, make less pieces of the "F", "Z", and "A." Be sure to have some representation for each part of the food chain.

Activity Facilitation:

Explain that biomagnification is when organisms accumulate chemical residues from the organisms they are eating underneath them in the food chain. An animal higher up on the food chain would tend to have a greater concentration of chemical. While there might be very little concentration in the tissue of an organism at the bottom of the food chain, as you go up the food chain, the concentration can increase, as the creature at the top of the food chain can have the highest concentration of pesticide residue in them.

For this activity, explain that a body of water has a low amount of contamination, such as from a pesticide. From the food chain, organisms can pick up those contaminants, beginning with the planktonic algae that incorporate the contaminated water into their tissues. Zooplanktons consume the planktonic algae. The level of residue in the each organism up the food chain continues to rise, as fish eat the zooplankton. At the top of the food chain, a bird would eat the fish, in which the bird would contain a higher amount of residue. Even as the level of contaminant is initially very low in the water, biomagnification occurs when organisms accumulate chemical residues from the organisms they are eating underneath them in the food chain.

  1. Distribute the pieces of papers to participants. Explain to participants that the "P" represents planktonic algae, the "Z" represents zooplankton, the "F" represents fish, and the "B" represents bird. Explain how the ".5" on the planktonic algae represents the amount in parts per million of chemical that was taken up by the algae from the contaminated water. Review the food chain if necessary, in that the planktonic algae are eaten by the zooplankton, the zooplanktons are eaten by the fish, and the fish are eaten by the birds.
  2. Have the students with "P" on their paper, representing the planktonic algae, stand up and come to the center of the room. Ask participants what creature would eat the planktonic algae; response would be zooplankton. Have participants demonstrate the food chain, instructing the zooplankton (participants with the "Z" on their card) to stand and "eat" the planktonic algae by going to the center of the room and collecting the pieces of paper from the planktonic algae. Zooplankton may eat more than one planktonic algae.
    The zooplankton should then calculate the amount of chemical concentration in them. For example, if a zooplankton collected two pieces of paper from the algae, with ".5" on each piece, they would add. 5 +. 5 to get 1. The zooplankton participant would then write "1" on their paper underneath the "Z" to represent having "1" parts per million of chemical in them.
  3. Have the zooplankton remain in the center of the room. Ask participants what creature would eat the zooplankton; response would be fish. Have participants demonstrate the food chain, instructing the fish (participants with the "F" on their card) to stand and "eat" the zooplankton by going to the center of the room and collecting the pieces of paper from the zooplankton. Fish may eat more than one zooplankton.
    The fish should then calculate the amount of chemical concentration in them. For example, if a fish collected two pieces of paper from the zooplankton, with "1" on each piece, they would add 1 + 1 to get 2. The fish participant would then write "2" on their paper underneath the "F" to represent having "2" parts per million of chemical in them. (If the fish only collect one piece of paper from the zooplankton, they would write that amount on their paper.)
  4. Have the fish remain in the center of the room. Ask participants what creature would eat the fish; response would be the bird. Have participants demonstrate the food chain, instructing the bird (participants with the "B" on their card) to stand and "eat" the fish by going to the center of the room and collecting the pieces of paper from the fish. The bird may eat more than one fish.
    The bird should then calculate the amount of chemical concentration in them. For example, if a bird collected three pieces of paper from the fish, with "2," "2," and "1.5" written on each piece, they would add 2 + 2 + 1.5 to get 5.5. The bird participant would then write "5.5" on their paper underneath the "B" to represent having "5.5" parts per million of chemical in them.

Conclude the activity by reviewing the definition of biomagnification with learners and discussing how the activity represents how organisms accumulate chemical residues from the organisms they are eating underneath them in the food chain.