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Images: How Does Nature Deal with Persistent Pollutants?

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)

>MIT/WHOI graduate student Kristin Pangallo started her research with blubber saved from whales that died after being stranded on beaches. She puts the blubber through an elaborate process to produce samples of whale extract Subsequently, she has examined animals further down the food chain. Above is a flask of squid extract. (Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)

MIT/WHOI graduate student Kristin Pangallo then purifies her marine animal extracts further to extract biomagnifiying chemicals, including naturally occuring ones that have existed for eons. Those chemicals could help us learn how to deal with more recently introduced man-made pollutants that are accumulating in marine life. (Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)