Photodegradation of plastics The North Atlantic patch is one of several oceanic regions where researchers have studied the effects and impact of plastic
photodegradation in the neustonic layer of water. Unlike organic debris, which
biodegrades, plastic disintegrates into ever smaller pieces while remaining a
polymer (without changing chemically). This process continues down to the molecular level. Some plastics decompose within a year of entering the water, releasing potentially toxic chemicals such as
bisphenol A,
PCBs and derivatives of
polystyrene. As the plastic
flotsam photodegrades into smaller and smaller pieces, it concentrates in the upper water column. As it disintegrates, the pieces become small enough to be ingested by aquatic organisms that reside near the ocean's surface. Plastic may become concentrated in
neuston, thereby entering the
food chain. Disintegration means that much of the plastic is too small to be seen. Moreover, plastic exposed to sunlight and in watering environments produce
greenhouse gases, leading to further environmental impact.
Effects on marine life The
2017 United Nations Ocean Conference estimated that the oceans might contain more weight in plastics than fish by the year 2050. Some long-lasting plastics end up in the stomachs of marine animals. Plastic attracts seabirds and fish. When marine life consumes plastic allowing it to enter the food chain, this can lead to greater problems when species that have consumed plastic are then eaten by other predators. Animals can also become trapped in plastic nets and rings, which can cause death. Plastic pollution affects at least 700 marine species, including sea turtles, seals, seabirds, fish, whales, and dolphins. Cetaceans have been sighted within the patch, which poses entanglement and ingestion risks to animals using the Great Pacific Garbage Patch as a migration corridor or core habitat.
Plastic consumption that displays plastic bags in the ocean that look similar to
jellyfish. With the increased amount of plastic in the ocean, living organisms are now at a greater risk of harm from plastic consumption and entanglement. Approximately 23% of aquatic mammals, and 36% of seabirds have experienced the detriments of plastic presence in the ocean. Since as much as 70% of the trash is estimated to be on the ocean floor, and
microplastics are only millimeters wide, sealife at nearly every level of the food chain is affected. Animals who feed off of the bottom of the ocean risk sweeping microplastics into their systems while gathering food. Smaller marine life such as mussels and worms sometimes mistake plastic for their prey. Larger animals are also affected by plastic consumption because they feed on fish, and are indirectly consuming microplastics already trapped inside their prey.
Deposits on landmasses Research in 2017 reported "the highest density of plastic rubbish anywhere in the world" on remote and uninhabited
Henderson Island in South Pacific as a result of the
South Pacific Gyre. The beaches contained an estimated 37.7 million items of debris together weighing 17.6 tonnes. In a study
transect on North Beach, each day 17 to 268 new items washed up on a 10-metre section. == References ==