BIOLOGICAL BIOLOGICAL MAGNIFICATIONMAGNIFICATION

By:

Matt and Kristi

What Is Biological Magnification?• A trophic process in

which retained substances(ex: pesticides or heavy metals) become more concentrated with each link in the food chain

• Similar to bioaccumulants: Toxic substance (ex:heavy metals and polychlorinated biphenyls) that slowly builds up in concentration in living organisms (including bacteria, algae, fungi, and plants).

Why Does It Happen?

• Because the biomass at any given trophic level is produced from a much larger biomass ingested from the level below, thus meaning the top carnivores are most affected

Examples• Biological magnification of chlorinated

hydrocarbons, which includes many pesticides, such as DDT and PCB (polychlorinated biphenyls)

• PCB in Great Lakes affect food chain with affecting the herring gull eggs nearly 5,000 times greater than in phytoplankton

• DDT (1950s) travels in water to places, and first sign was when populations of pelicans, ospreys, and eagles, and birds at the top of the food chain, were decreasing

• Build up of DDT in the bird’s tissue interfered with the deposition of calcium in their eggs, thus making the eggs to weak to be incubated by the parents, they just break