Marine Debris - Environmental Impact

Environmental Impact

Many animals that live on or in the sea consume flotsam by mistake, as it often looks similar to their natural prey. Bulky plastic debris may become permanently lodged in the digestive tracts of these animals, blocking the passage of food and causing death through starvation or infection. Tiny floating plastic particles also resemble zooplankton, which can lead filter feeders to consume them and cause them to enter the ocean food chain. In samples taken from the North Pacific Gyre in 1999 by the Algalita Marine Research Foundation, the mass of plastic exceeded that of zooplankton by a factor of six.

Toxic additives used in plastic manufacturing can leach into their surroundings when exposed to water. Waterborne hydrophobic pollutants collect and magnify on the surface of plastic debris, thus making plastic more deadly in the ocean than it would be on land. Hydrophobic contaminants bioaccumulate in fatty tissues, biomagnifying up the food chain and pressuring apex predators. Some plastic additives disrupt the endocrine system when consumed; others can suppress the immune system or decrease reproductive rates.

Not all anthropogenic artifacts in the oceans are harmful. Iron and concrete typically do little damage to the environment as they generally sink to the bottom and become immobile, and can even provide scaffolding for artificial reefs. Ships and subway cars have been deliberately sunk for that purpose. Some organisms have adapted to live on floating plastic debris, allowing them to disperse all over the world and become invasive species in remote ecosystems.