The Ocean’s Microplastic Crisis

Written by Benjamin Taubman

Research and Writing Intern Learn More About Benjamin

November 3, 2022

Barbie Loves the Ocean, Hates Plastic

Last year, the toy company Mattel released a sustainable Barbie named “Barbie Loves the Ocean.” The doll aims to teach children about ocean conservation and is manufactured from 90% “ocean-bound plastic” (i.e., plastic that is likely to end up in the ocean due to a lack of proper waste management and recycling facilities). Without these facilities, plastic is improperly disposed of and can end up in rivers and other ocean-connecting waterways that eventually carry the waste out to sea [1]Mattel Launches Barbie Loves the Ocean; Its First Fashion Doll Collection Made from Recycled Ocean-Bound* Plastic | Mattel, Inc. Corporate.Mattel.com … Continue reading.

Whether you still play with Barbies or not – no judgment – the doll sheds light on the ocean’s plastic waste crisis; one that is nothing to toy about. To understand the severity of the issue, let us learn about plastic’s history.

Plastic – the Material of the Future?

The global production and use of plastics date back to the 1950s. Durable, lightweight, and versatile, plastic became a staple component of modern, manufactured goods. Nowadays, its ubiquity is rivaled only by construction materials like steel and cement [2]Geyer, R., Jambeck, J. R. & Law, K. L. Production, use, and fate of all plastics ever made. Sci. Adv. 3, e1700782 (2017)..

While most goods in the time before plastic were created to last, products in the time thereafter were more disposable. In fact, most plastics are destined to be made into single-use packaging materials. In 2015, about 42% of plastics produced were used as containers, condiment squeeze bottles, lids, grocery bags, and, most infamously, water bottles. Although many of us dispose of plastic after a single use, plastic itself is permanent. Plastic is not biodegradable, and unless it is destroyed thermally, it will exist in the environment forever. Each year, the amount of plastic completely destroyed pales compared to the amount sent to landfills. To date, 12% of plastics produced have been thermally destroyed (A still-harmful option that releases carbon dioxide and toxic gasses into the atmosphere) while 79% have been sent to accumulate in landfills [3]Geyer, R., Jambeck, J. R. & Law, K. L. Production, use, and fate of all plastics ever made. Sci. Adv. 3, e1700782 (2017)..

Putting the Plastic Problem into Perspective

In 2010, it is estimated that humans generated more than 275 million metric tons of plastic waste; between 4.8 to 12.7 million metric tons of which entered the world’s oceans[4]Jambeck, J. R. et al. Plastic waste inputs from land into the ocean. Science 347, 768–771 (2015).. It is estimated that there are over 5.45 trillion individual pieces of plastic, which collect in enormous clusters on the ocean’s surface (the most well-known of which is the infamous Great Ocean Garbage Patch). Most of this plastic is found in the Earth’s three largest ocean basins: the Pacific (44%), the Atlantic (26%), and the Indian (22%) [5]Eriksen, M. et al. Plastic Pollution in the World’s Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea. PLOS ONE 9, 1–15 (2014).. Around 80% of this plastic enters the ocean through land-based sources such as litter on beaches, industrial emissions, and discharge from storm drains. The remaining 20% comes from sea-based sources such as offshore mining and illegal dumping [6]Anderson et al. Sources, fate and effects of microplastics in the marine environment (Part 1). (98p.) http://www.gesamp.org/publications/reports-and-studies-no-90 (2015)..

Although images of floating water bottles, shopping bags, colorful straws, and single-use utensils spring to mind when picturing marine plastic waste, that is just the tip of the iceberg: millions of tons of plastic have also insidiously sunk below the waves. Plastic has even been found in some of the deepest and most untouched marine environments. This includes the Charlie-Gibbs Fracture Zone of the Mid-Atlantic Ridge, which lies over 8,000 feet beneath the ocean’s surface[7]Law, K. L. Plastics in the Marine Environment. Annu. Rev. Mar. Sci. 9, 205–229 (2017).. 

It’s clear: plastics are now ubiquitous in the ocean. What effect does it have on marine ecosystems?

Plastic in the Ocean

In 1975, Scientists from the U.S. National Research Council first published a report on the harmful effects of plastic on marine life, outlining how marine plastic waste can impair underwater navigation, lead to death by entanglement, and obstruct animal organs when ingested. Since that report was released, hundreds of publications have gone on to document how marine plastic has harmed over 700 species [8]Law, K. L. Plastics in the Marine Environment. Annu. Rev. Mar. Sci. 9, 205–229 (2017).. 

Two noteworthy studies discovered that 95% of beached seabird carcasses in the North Sea contained plastic in their stomachs and that 83% of North Atlantic right whales (Eubalaena glacialis), a critically endangered species, photographed in 29 years had evidence of at least one entanglement in rope or netting [9]Law, K. L. Plastics in the Marine Environment. Annu. Rev. Mar. Sci. 9, 205–229 (2017).. In recent years, scientists have continued to study cases like the ones above, but have begun exploring research on a more microscopic, yet still hazardous category of plastics: microplastics. 

Microplastics; Primary and Secondary

Although there is no formal definition for microplastics, the term generally describes plastic particles between 5 millimeters and 1 nanometer (a billionth of a meter), although it is often used as a catch-all term for “small” pieces of plastic. Within the category of microplastics, there are two subcategories: primary and secondary microplastics [10]Anderson et al. Sources, fate and effects of microplastics in the marine environment (Part 1). (98p.) http://www.gesamp.org/publications/reports-and-studies-no-90 (2015)..

Primary microplastics are microplastics that were manufactured to be that size. Some examples of this include microfibers from synthetic fabrics, 3D printing powders, and microbeads that used to be found in rinse-off cosmetic products such as face and body wash [11]Anderson et al. Sources, fate and effects of microplastics in the marine environment (Part 1). (98p.) http://www.gesamp.org/publications/reports-and-studies-no-90 (2015).. Fortunately, these microbeads were banned in 2015 after public concern led to the passing of The Microbead-Free Waters Act. The new law completely prohibited the manufacturing, packaging, and distribution of rinse-off cosmetics containing plastic microbeads[12]Pallone, F. H.R.1321 – 114th Congress (2015-2016): Microbead-Free Waters Act of 2015. http://www.congress.gov/ (2015)..

Not all microplastics, however, begin that small. Secondary microplastics are microplastics that result from the breakdown of larger plastic objects such as water bottles, PVC construction pipes, and children’s toys. Plastics can be broken down mechanically (e.g., knocking into other objects), but plastics in the ocean are especially susceptible to breakdown from continued exposure to the sun’s ultraviolet (UV) light, a phenomenon known as photodegradation[13]Yousif, E. & Haddad, R. Photodegradation and photostabilization of polymers, especially polystyrene: review. Springerplus 2, 398 (2013)..

The Effects of Microplastics on Marine Life

Whether microplastics are the result of the breakdown of plastic or were just made that way, they are equally harmful to marine life. For example, a 2013 study found that Japanese medaka fish (Oryzias latipes) exposed to microplastics collected from marine environments suffered liver disease and toxicity [14]Rochman, C. M., Hoh, E., Kurobe, T. & Teh, S. J. Ingested plastic transfers hazardous chemicals to fish and induces hepatic stress. Sci Rep 3, 3263 (2013).. In a 2016 lab study, researchers found that the reproductive systems of Pacific oysters (Crassostrea gigas) exposed to microplastics had severe deficiencies. After two months of exposure to the plastics, the oysters had a 38% decrease in oocyte number and a 23% decrease in sperm mobility, which describes the ability of sperm to properly move through the reproductive tract [15]Sussarellu, R. et al. Oyster reproduction is affected by exposure to polystyrene microplastics. Proc. Natl. Acad. Sci. U.S.A. 113, 2430–2435 (2016)..

Microplastics aren’t only harmful to the marine animals that ingest them – their effects can be seen in the animals that eat them, too.

Microplastics Up the Food Chain

Marine microplastics not only affect marine life but also everything that eats marine life, including humans. The “food chain” is an ecological concept that many people learn early on in environmental science classes, and this simple concept has huge implications for the effects of microplastics on human health. As a refresher, the food chain simply describes how species are eaten by predators, which themselves are subsequently preyed upon other species[16]Egerton, F. N. Understanding Food Chains and Food Webs, 1700–1970. The Bulletin of the Ecological Society of America 88, 50–69 (2007).. This chain can be many linkages long and ends with an apex predator: a species with no natural predators.

Although an animal as an entity ceases to exist when it is eaten, many of the compounds inside it do not. Nutrients like proteins and carbohydrates are broken down or excreted, but things like heavy metals and microplastics, are not. Instead, they remain inside the predator, increasing in levels every time they eat [17]Miller, M. E., Hamann, M. & Kroon, F. J. Bioaccumulation and biomagnification of microplastics in marine organisms: A review and meta-analysis of current data. PLoS One 15, e0240792 (2020)..


It is important to appreciate how quickly levels of something like microplastics can accumulate as you go up the food chain. A predator might eat thousands of prey animals in its lifetime, each of which has a small amount of microplastics in it, and an apex predator may eat hundreds of that predator; every time you move up the food chain, the biomagnification of microplastics becomes more pronounced. Humans eat many animals that are high in their food chains, so we can end up getting a considerable dose of these microplastics [18]Miller, M. E., Hamann, M. & Kroon, F. J. Bioaccumulation and biomagnification of microplastics in marine organisms: A review and meta-analysis of current data. PLoS One 15, e0240792 (2020)..

The concerns of the biomagnification of microplastics are supported by the research: In a 2015 study, scientists purchased commonly consumed fish species, such as tilapia and albacore tuna (Thunnus alalunga), from seafood markets in both California and Indonesia. In the 64 Californian fish purchased, the researchers found that 16 (25%) had microplastics in their GI tract. Of the 76 Indonesian fish purchased, 21 (28%) had microplastics in their GI tract[19]Rochman, C. M., Hoh, E., Kurobe, T. & Teh, S. J. Ingested plastic transfers hazardous chemicals to fish and induces hepatic stress. Sci Rep 3, 3263 (2013).. When someone buys these potentially contaminated fish to serve for commercial consumption in a restaurant, or to feed their family, the microplastics end up being ingested into the human body.

Upon consumption, the human body’s excretory system eliminates more than 90% of microplastics via stool excretion. The remaining microplastics can cause inflammatory responses, transfers of chemical pollutants into cells, and disruption of the gut microbiome, an important colony of bacteria and microorganisms that help the human digestive system absorb nutrients. Altogether, the ingested microplastics shift the microorganism structure of the gut, affecting overall digestive health [20]Blackburn, K. & Green, D. The potential effects of microplastics on human health: What is known and what is unknown. Ambio 51, 518–530 (2022)..Research also suggests that microplastics cause toxicity to the lungs and liver, and can pass the blood-brain barrier into brain cells.

Additionally, Microplastics also contain dangerous endocrine-disrupting chemicals. 2019 research found that microplastics harvested from marine environments contained high concentrations of estrogen, an endocrine-disrupting chemical that can cause adverse effects to organisms. Although microplastics already have demonstrated toxicity to humans, research on their dangerous effects is still in the early stages and not yet fully realized.

The Plasticene Epoch

The production and distribution of plastics in the world have become so widespread and extreme that scientists have defined this plastic society as a new historical age: The Plasticene Epoch. Our society’s plastic problem is larger than life itself and there is no magic solution that will make it go away. 

However, there are avenues to mitigate the problem. Protest and press the government and large corporations to limit the manufacture of single-use plastics, reduce the use of single-use plastics at an individual level, buy goods that are produced with recycled plastics, and donate to organizations that promote oceanic sustainability such as The Ocean Cleanup or the Surfrider Foundation. Barbie loves the ocean – so should everyone else.

Benjamin Taubman
Benjamin Taubman

Research and Writing Intern

Learn More About Benjamin

References

References
1 Mattel Launches Barbie Loves the Ocean; Its First Fashion Doll Collection Made from Recycled Ocean-Bound* Plastic | Mattel, Inc. Corporate.Mattel.com https://corporate.mattel.com/news/mattel-launches-barbie-loves-the-ocean-its-first-fashion-doll-collection-made-from-recycled-ocean-bound-plastic (2021).
2, 3 Geyer, R., Jambeck, J. R. & Law, K. L. Production, use, and fate of all plastics ever made. Sci. Adv. 3, e1700782 (2017).
4 Jambeck, J. R. et al. Plastic waste inputs from land into the ocean. Science 347, 768–771 (2015).
5 Eriksen, M. et al. Plastic Pollution in the World’s Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea. PLOS ONE 9, 1–15 (2014).
6, 10, 11 Anderson et al. Sources, fate and effects of microplastics in the marine environment (Part 1). (98p.) http://www.gesamp.org/publications/reports-and-studies-no-90 (2015).
7, 8, 9 Law, K. L. Plastics in the Marine Environment. Annu. Rev. Mar. Sci. 9, 205–229 (2017).
12 Pallone, F. H.R.1321 – 114th Congress (2015-2016): Microbead-Free Waters Act of 2015. http://www.congress.gov/ (2015).
13 Yousif, E. & Haddad, R. Photodegradation and photostabilization of polymers, especially polystyrene: review. Springerplus 2, 398 (2013).
14, 19 Rochman, C. M., Hoh, E., Kurobe, T. & Teh, S. J. Ingested plastic transfers hazardous chemicals to fish and induces hepatic stress. Sci Rep 3, 3263 (2013).
15 Sussarellu, R. et al. Oyster reproduction is affected by exposure to polystyrene microplastics. Proc. Natl. Acad. Sci. U.S.A. 113, 2430–2435 (2016).
16 Egerton, F. N. Understanding Food Chains and Food Webs, 1700–1970. The Bulletin of the Ecological Society of America 88, 50–69 (2007).
17, 18 Miller, M. E., Hamann, M. & Kroon, F. J. Bioaccumulation and biomagnification of microplastics in marine organisms: A review and meta-analysis of current data. PLoS One 15, e0240792 (2020).
20 Blackburn, K. & Green, D. The potential effects of microplastics on human health: What is known and what is unknown. Ambio 51, 518–530 (2022).

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