One of the major consequences of ecosystem dynamics relative to human influence is biomagnification. Biomagnification is the increasing concentration of persistent and toxic substances in organisms at each successive trophic level. These are fat-soluble substances that are stored in the fat reserves of every organism.
Many substances have been shown to biomagnify, including classic studies with the pesticide dichlorodiphenyltrichloroethane (DDT) described in the 1960s bestseller Silent Spring by Rachel Carson. DDT was a commonly used pesticide before its dangers to large consumers such as the bald eagle became known. Producers are absorbing DDT and other toxins and passing them on to consumers at ever-increasing rates. As bald eagles feed on contaminated fish, their DDT levels increase. DDT was found to cause bird eggshells to become brittle, which contributed to the bald eagle being classified as an endangered species under US law. The use of DDT was banned in the United States in the 1970s.
Another substance that biomagnifies is polychlorine biphenyl (PCB), which is found in It was used as a coolant in the United States in 1 until its use was banned in 1979. PCBs have been best studied in aquatic ecosystems, where predatory fish species accumulated very high levels of toxin, which is otherwise found at low levels in the environment.
For example, the main consumer, walleye, contains four times more PCBs than phytoplankton. In addition, the research found that birds eating these fish may have levels of PCBs at least 10 times higher than those found in marine fish. Other concerns have been raised regarding the biomagnification of heavy metals such as mercury and cadmium in certain species of sea animals.
The US EPA Protection Agency recommends that pregnant women and young children not consume swordfish, shark, mackerel, or tilefish because of their high mercury content. These people are advised to eat fish that are low in mercury: salmon, shrimp, pollock, and catfish. Biomagnification is a good example of how ecosystem dynamics can affect our daily lives, including affecting the food we eat.