• Bioaccumulation: the accumulation of substances inside living organisms, when those substances are ingested faster than
they are excreted.
• It may help to break down this term into its word parts: accumulation, or the gathering together of a substance, and bio-,
or life.
• It is also important to note that, although some pollutants like methylmercury bioaccumulate, many others do not.
Simulating Biomagnification (~10 minutes)
Do mummichogs eat anything other than plants?
• Mummichogs also eat animal matter, like zooplankton and copepods.
• Each student with a mummichog cup “consumes” a few zooplankton and copepods by transferring the contents of the zooplankton and copepod cups into their own.
Would mummichogs eat just part of a zooplankton or copepod, or the entire thing?
• They would eat the entire thing, so the students with zooplankton and copepod cups should pour the entire contents of
their cups into the mummichog cups.
• Students observe the mummichog cups and record their observations (Observation Worksheet).
• Students should observe that the mummichogs now contain several times as much methylmercury as before.
The mummichogs are now almost full. Remind me: what do organisms do when they are full?
• Students should identify the mummichogs’ need to excrete waste.
• Students with mummichog cups should “excrete waste” by pouring some of the contents of their cups back into the bowl(s)
of water.
The striped bass have not eaten yet. What do they eat?
• The striped bass eat mummichogs and other animals.
• Each student with a striped bass cup “consumes” a few mummichogs by transferring the entire contents of the mummichogs’ cups into their own.
• Students observe the striped bass cups and record their observations (Observation Worksheet).
• Students should observe that the striped bass now contain many times as much methylmercury as they did originally.
What if a human caught these striped bass and ate them?
• Students should predict that the methylmercury in the striped bass would transfer to the human.
• Students with striped bass cups empty their cups into the largest cup held by the instructor, who represents a human.
• Students observe the human cup and record their observations (Observation Worksheet).
• Students should observe that the human now contains all of the methylmercury.
• Biomagnification: the process by which environmental contaminants are concentrated in living organisms at the top of the
food chain.
• Again, this term can be broken down into its parts: magnification, or getting bigger or more concentrated, and bio-,
or life.
