Biomagnification occurs when contaminants that don’t easily degrade increase with each link of a food chain. In seawater, these persistent molecules stick to small particles and
phytoplankton. Small fish eat the phytoplankton, but the contaminants
can’t be broken down and are absorbed, intact, by the fish. When small
fish are eaten by larger predators, the process repeats—again and
again, up the food chain. Each subsequent predator receives a higher
dose than the previous one. Animals at the top of the food chain, such
as dolphins, receive the most concentrated dose of these contaminants
with every meal. MIT/WHOI graduate student Kristin Pangallo is studying naturally produced, persistent molecules—a halogenated 1' -methyl-1,2' -bipyrrole, or MBP (above)—found in marine mammal blubbler to help learn more about what happens to man-made persistent chemicals in the environment.
(Illustration by E. Paul Oberlander, Woods Hole Oceanographic Institution)[back]
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