Pollutants can make their way into the oceans from a variety of sources, including litter, oil spills, and toxic chemicals and metals from factories, communities, and households. These contaminants greatly affect the health of animals and plants of ocean organisms, and the entire ecosystems in which they live.

An example of a major ocean catastrophe occurred in 1989, when the Exxon Valdez spilled almost 11 million gallons of oil into Prince William Sound off the coast of Alaska. Clean-up efforts began approximately 12 hours after the spill occurred, with the placing of containment booms around spill to prevent it from spreading. Despite the remediation efforts, many animal populations were still not fully recovered years after the oil spill. One troublesome problem has been bioaccumulation, the process by which contaminants and pollutants accumulate in the tissues of organisms and become concentrated as they are passed up the food chain. This has been linked to the declining health and reproduction of organisms that live in Prince William Sound's ecosystems.