Ingestion: Marine animals can mistake plastic debris for food, leading to ingestion. Some plastics resemble plankton, small fish, or other prey, making them attractive to marine species. Ingesting plastic can cause damage to the animal's digestive system and can even lead to starvation if the plastic becomes lodged in the digestive tract.
Blockage: Plastic can also cause physical blockages in marine animals. For example, plastic bags can block the blowholes of whales and dolphins, leading to death by suffocation. Turtles can become entangled in plastic fishing line or strapping bands, restricting their movement and causing injury or even death.
Entanglement: Many marine species can become entangled in plastic debris. This can occur when they swim through plastic waste or when they become trapped in discarded fishing gear, known as "ghost nets." Entanglement can restrict an animal's movement and feeding, causing injury, infection, and eventually leading to death.
Toxic Chemicals: Plastic contains various toxic chemicals used in its production, such as phthalates, bisphenol A (BPA), and heavy metals. These substances can leach into the water and accumulate in the bodies of marine organisms, potentially affecting their health and reproduction. Some plastic additives can also alter the animals' behavior and immune system.
Habitat Disruption: Plastic debris can alter or damage marine habitats. Large plastic items like bottles or discarded fishing nets can smother coral reefs, hindering their growth and reducing habitat complexity for fish and other marine life. Microplastics can accumulate on the seafloor, altering the composition and structure of the marine environment.
Food Chain Impact: Plastic ingestion and entanglement can have severe consequences throughout the marine food chain. As predators consume smaller animals that have ingested plastic, they accumulate plastic in their bodies as well. This can cause health issues and eventually affect top predators, including species that are important to human fisheries.
Additionally, plastic pollution can introduce invasive species. Non-native species can attach to plastic debris and be transported to new areas, where they may outcompete native species and disrupt the local ecosystem.
Given these risks, reducing plastic pollution and managing plastic waste effectively are critical to protecting marine life and preserving the health of our oceans.