Plastics have become a daily part of people’s lives. They are present in nearly every product that you buy or use and have replaced many other materials because of how inexpensive and versatile they are. Unfortunately while plastics have become so common in the products people use, they have also become common as debris in the ocean. It is estimated that of the almost seven billion tons of debris entering the world’s oceans, about sixty percent is plastic. The problems and contamination associated with plastic materials in the World’s oceans are quite vast and greatly affect marine life.
Plastics in the oceans
Bags, bottles, and other common objects are what people commonly think of when they hear ‘plastic debris in the oceans’. However, what some people may not know is that plastic debris is also present in many different forms and sizes. Plastic debris can be found in the oceans from as small as microscopic particles of polyethylene all the way to very large objects such as crates, floats, and even fishing lines and nets discarded from fishing ships. Regrettably, no matter what form the plastic comes in, or what types of plastic it is, it will affect the world’s oceans and the animals that live there.
Problems for ocean animals
Of the many animals present in the ocean, at least two hundred sixty seven have been known to suffer from ingestion of plastics or from entanglement in plastic materials. These animals include whales, dolphins, manatees, porpoises, sea lions, seabirds, sea turtles, and many types of fish. Animals can be injured or even die from either ingesting or being entangled by plastic materials.
Ingestion
Plastic can become ingested either by accident or through ingesting other animals that have ingested plastics. It is estimated that nearly half of all sea birds have or will mistakenly ingest plastics because they believe it to be something else. Animals have also been known to ingest floating plastic bags because they were mistaken as jellyfish. The microscopic plastic particles mentioned early have been known to be eaten by plankton, which in turn get eaten by a variety of different fish and whale species. Larger pieces of plastic up to an inch or so can also be eaten by many of the variety of different fish in the ocean. So they may unknowingly ingest amounts of plastic without realizing it. The ingestion of Plastics can cause animals to die from either drowning or suffocation. A buildup of plastic in the stomach can also cause many problems for the animal as they are unable to eat the proper amount of food to survive because the plastic will stay in the stomach and not pass through the animal. Should the plastics begin to degrade or give off any toxins, these will also be absorbed by the animal.
Entanglement
Items from discarded fishing gear such as nets and lines as well as smaller plastics like six-pack rings can be harmful to marine life. Animals can be killed or injured from becoming entangled in these kinds of plastic materials. Becoming trapped, they could suffer wounds or become mangled, starved, suffocated, or even drown as a result. The term ‘ghost fishing’ is often used to describe the phenomenon of ocean animals become trapped in discarded fishing equipment. Despite the equipment no longer being used, it is still capturing or trapping fish as it moves through the oceans by the currents. It is even possible that coral reefs can be damaged by this equipment. Estimates as high as fifty percent of all sea lion and seal species have been entangled by some form of plastic material. Reports of other species such as whales, turtles, seabirds, and dolphins becoming entangled in plastics are also common.
Decomposition of plastics
Whereas it was once thought that plastics would take possibly hundreds of years to decompose under high temperatures, recent studies show that is not the case. New information shows that plastics can break down much faster than expected at cooler temperatures, perhaps only a few years. Samples collected from waters in oceans around the world showed derivatives of several different plastics like polystyrene. These chemicals were coming from the plastic materials that have ended up in the ocean. The samples of water contained chemicals like bisphenol A (chemical used in hard plastics) and styrene trimmer (by-product of polystyrene). Both of these chemicals can cause serious problems for ocean life as styrene trimmer is a possible carcinogen while bisphenol A has been known to affect the reproductive systems of animals. The study also showed that areas with more plastic debris had higher concentrations of these compounds. These are just a few of the chemicals that result from the decomposition of plastics.
The situation in the ocean may actually be much worse as plastics are known to accumulate chemicals on their surface, so plastics that are ingested would be much more toxic to ocean animals because of this accumulation. Considering that humans are at the top of the food chain this becomes very problematic from a human health standpoint. The plastics are also not just present on the surface of the ocean. Plastic debris as small as a fifth of an inch or less may be dispersed deep into the water column (several miles deep) of the ocean and over millions of square miles of the surfaces. This effectively makes the ocean a ‘plastic soup’ of potential harmful debris that will negatively affect ocean animals and possibly even humans.
Sources
http://news.nationalgeographic.com/news/2009/08/090820-plastic-decomposes-oceans-seas.html
http://www.unep.org/regionalseas/marinelitter/publications/docs/plastic_ocean_report.pdf
http://www.eco-pros.com/humanimpact.htm
http://www.lurj.org/article.php/vol3n2/plastic.xml
