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Plastic in the Oceans

Early in the movie Finding Dory, the lovable blue tang gets caught in a plastic six pack ring, a problem that she barely notices. Dory just keeps swimming. But that little piece of trash represents an estimated 5.25 trillion pieces of plastic that have found their way to the ocean (Parker 2015a).

The Accumulation of Plastic in the Ocean

Early in the movie Finding Dory, the lovable blue tang gets caught in a plastic six pack ring, a problem that she barely notices. Dory just keeps swimming. But that little piece of trash represents an estimated 5.25 trillion pieces of plastic that have found their way to the ocean (Parker 2015a). With serious implications for the health of marine life and humans and


Plastic is dangerous to ocean wildlife.

associated impacts on the fishing industry, we should all be worrying like Marlin when it comes to the accumulation of plastic in the ocean.

What is plastic?

You probably see and use plastic every day, but you may not know what it actually is. Plastics are synthetic, meaning that they are man-made; they are not found in nature. Most plastics are made from oil or natural gas which provide the organic, or carbon-based, compounds that make up each piece of plastic. The individual molecules of the organic compound are called monomers. Plastics are made of chains of monomers called polymers. The process of making plastics is called polymerization ( 2007).

Where does ocean plastic come from?

When plastic escapes collection systems, it is referred to as ‘leaking’. An estimated 32% (8 million metric tons) of plastic leaks every year and ends up in the ocean. This is the equivalent of dumping one garbage truck into the ocean every  minute  (Project  MainStream  2016).  Plastic  debris includes  household  items  like  bags,  cups,  and  bottles;  industrial products like plastic sheeting and hard hats; and   fishing gear like nets, buoys, traps, and lines. Pieces smaller than 5 mm are called Microplastics include large pieces that have broken down and items like the microbeads found in some cosmetics (NOAA 2016).

discarded fishing equipment, but by far the majority of it comes from land. Beach litter gets washed out to sea and inland litter makes its way to the ocean via streams and rivers (Parker 2014). In developing countries, illegal dumping into waterways is also a significant contributor to ocean debris because it is cheaper than regulated refuse management. These countries also often have open dumps that do not control for leaking because their infrastructure has not kept pace with economic growth (Ocean Conservancy 2015). Although ocean plastic is a global problem, the vast majority of it comes from developing nations, with 80% originating in rapidly growing Asian countries (Project MainStream 2016).

Where does ocean plastic go?

For a long time, scientists only measured the plastic that floated on top of the ocean but more recent studies have shown that this is just the tip of the proverbial iceberg. The actual amount could be as much as 20 – 2,000 times greater than what we can see (Parker 2015b). 

Large amounts of surface plastic have collected in five gyres, or swirls of ocean currents. These collections of plastic are called ‘garbage patches’ and are found in the Atlantic, Pacific, and Indian Oceans. The largest  of these is the Great  Pacific Garbage Patch (Parker 2014), although the name is misleading. The patch is not one massive island of trash, as you might imagine, but a large area of the ocean with individual pieces floating in it. Some areas have a more noticeable build-up of plastic while in others; the trash is not easily observed. Because it is dispersed and because the shape of the patch changes with wind and ocean currents, it is difficult to measure how large the Great Pacific Garbage Patch is (NOAA 2016a). However, it has been estimated that it contains 480,000 pieces of plastic per square kilometer (Parker 2014). Plastic has also been found in the deep ocean and frozen in Arctic ice, and fish eat a large amount of the debris that invades their watery homes (Parker 2015b) . But the real answer to ‘Where does ocean plastic go?’ is ‘Nowhere.’ Plastic is not biodegradable, which means that it does not decay through the actions of living organisms ( 2016). It doesn’t rot. It will remain in the same form for hundreds of years before breaking down into smaller pieces of plastic. But it never goes away. The Law of Conservation of Mass tells us that mass cannot be created or destroyed (Sterner et al. 2011). Unless the plastic is physically removed from the ocean, it’s there forever.

Negative impacts

Unfortunately, it turns out that marine life loves eating plastic. A study on perch found that even when food was abundant, the fish would eat massive quantities of plastic. Perch who had eaten plastic lost their ability to smell predators, making them very vulnerable. Widespread plastic consumption could lead to large drops in population, which would devastate not just that species but disrupt the entire ecosystem (Hanson 2016). 

Eating plastic has also been linked to liver cancer, endocrine dysfunction, and reproductive problems in fish (Ocean Conservancy 2016). The problem is only made worse by the fact that plastic soaks up other pollutants in the water, becoming even more toxic and more dangerous to the animals who eat it. And the danger extends to the animals who eat those fish, including humans. Human health is affected (Hanson 2016) as is the fishing industry, which employs 55 million people around the world (Ocean Conservancy 2016).

Possible solutions

Some steps have been taken to cut down on the amount of plastic that ends up in the oceans each year. In 2002, Bangladesh outlawed single-use plastic bags and many other countries have followed suit, including China and Rwanda in 2008 and France in January 2016. In all, more than 25 countries have either banned or started taxing single-use plastic bags (Project MainStream 2016). Beginning in 2017, microbeads will be eliminated from rinse-off cosmetics in the United States, although other products will still contain them (Hanson 2016).

However, much more will have to be done to stem the tide of plastic flowing into the world’s oceans. Human plastic consumption is expected to double in the next twenty years and if left unchecked, experts predict that by 2050, there will be more plastic than fish in the ocean (Project MainStream 2016).


Reading Comprehension Questions

  1. What are polymers?

  2. What is the process of making plastics called?

  3. How much plastic leaks into the ocean each year?

  4. What is the largest ocean garbage patch called?

  5. What does biodegradable mean? Are plastics biodegradable?

  6. How long does plastic stay in the ocean and why?

  7. Name three problems fish develop after eating plastic.

  8. How does plastic in the ocean affect humans?

  9. Which country was the first to ban single-use plastic bags?

Extension Questions

  1. One possible solution to this problem is the creation of biodegradable plastics. How and from what are they made and what problems might there be with this solution?

  2. What is bioaccumulation and how does it relate to the problem of plastic in the ocean?

  1. (2016). Biodegradable. Retrieved 26 June 2016 from:

  2. Hanson, H. (2016, June 3). Fish freaking love to eat plastic and that’s a problem. Retrieved 26 June 2016 from:

  3. National Oceanic and Atmospheric Administration. (2016a). Great Pacific garbage patch. Retrieved 24 June 2016 from:

  4. National Oceanic and Atmospheric Administration. (2016b). Plastics. Retrieved 22 June 2016 from:

  5. (2007, August 28). Plastics and polymers: Plastics have changed the world. Retrieved 26 June 2016 from:

  6. Ocean Conservancy. (2015, September). Stemming the tide: Land-based strategies for a plastic free ocean. New York: McKinsey & Company.

  7. Parker, L. (2014, April 16). The best way to deal with ocean trash. Retrieved 23 June 2016 from:

  8. Parker, L. (2015, January 11). Ocean trash: 2.52 trillion pieces and counting, but big questions remain. Retrieved 22 June 2016 from:

  9. Parker, L. (2015, February 13). Eight million tons of plastic dumped in ocean every year. Retrieved 23 June 2016 from:

  10. Project MainStream. (2016, January). The new plastics economy: Rethinking the future of plastics. Geneva, Switzerland: World Economic Forum.

  11. Sterner, R. W., Small, G. E. & Hood, J. M. (2011) The conservation of mass. Nature Education

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