When Plastic Outnumbers Plankton: Insights into the Great Pacific Garbage Patch

“As I gazed from the deck at the surface of what ought to have been a pristine ocean, I was confronted, as far as the eye could see, with the sight of plastic.”

–          Capt. Charles Moore, discoverer of the Great Pacific Garbage Patch

 

Moving along with the ocean currents are hundreds of pieces of plastic that have washed out to sea. The ocean’s currents collide to form rotating vortexes that deposit the traveling refuse and form huge swirling islands of trash known collectively as the Great Pacific Garbage Patch. Despite its name, the Great Pacific Garbage Patch is actually composed of two smaller patches connected by stream of debris jockeying between them along the North Pacific Subtropical Convergence Zone [1]. The Western Garbage Patch is located near Japan and the Eastern Garbage Patch is located between Hawaii and California. These patches are not static masses of solid garbage; they are constantly moving and growing. New waste is unfortunately constantly added to the oceans; a 2014 study indicated that 8 million metric tons of plastic trash enter the sea every year [2].

Plastic bottles, bags, and other debris are not biodegradable, but they are also not indestructible. Over time, the plastics break down into smaller and smaller pieces, ultimately becoming small particles known as micro-plastics. Micro-plastics are small pieces of plastic (less than 5mm) that transform the clear ocean water into thick, garbage slurry. Although micro-plastics may be small, their presence is causing a major concern about the current health of our marine ecosystems.

Micro-plastics are becoming ubiquitous in the ocean. Recent estimates place the number of plastic particles circulating in the ocean near 5.25 trillion particles [3]! Near the North Pacific Gyre of the Pacific Garbage patch, researchers found that micro-plastics were six times more abundant than zooplankton [3]. Of the micro-plastics that are found in the ocean, nylon and acrylic microfibers represent the largest constituent of man-made debris. These fibers originate from synthetic clothing: researchers estimate that as many as 1,900 individual fibers can be rinsed off from a single synthetic garment and eventually end up in our oceans. Not all of the micro-plastics in our ocean start out as part of a larger, macroscopic item. Tiny, non-degradable pieces of plastic are produced for many commercial products such as exfoliating face and body washes and for industrial manufacturing where they are used for plastic molding [3,4].

Micro-plastics are infiltrating every part of our ocean, even outside of the Great Pacific Garbage Patch. Coastal regions, in particular, are accumulating high levels of micro-plastics in the sand and waters. The impact of this accumulation is two-fold: micro-plastics deliriously impact the health of the marine ecosystems and our own health.

Microplastics collected in the United States on top of a penny. Photo Courtesy of the Associated Press.

So far, more than 180 species of animals are known to have ingested plastic debris from the ocean, including birds, fish, turtles and marine mammals, and much of this is micro-plastic. In fact, near ASEAN, in Australia’s Great Barrier Reef, corals were found to be consuming micro-plastics at high rates, most likely after mistaking the small particles for plankton [1]. Closer investigation showed that the consumed plastic remained wrapped in tissues around the coral gut, forming potentially hazardous polyps [1]. Physically, macro- and micro-plastic can harm sea life by physically obstructing or embedding within the digestive track. Chemically, these plastics also pose a serious risk; microplastics are offering dangerous chemicals a free ride into the bodies of marine animals.

The popular media coverage of Bisphenol A (BPA), a chemical believed to disrupt the human endocrine system, in water bottles highlighted the issue that plastic manufacturing relies on a number of hazardous components. Others include flame-retardants, antimicrobials, and polychlorinated biphenyls (PCBs), just to name a few. Once these plastics hit the ocean, their toxicity is actually likely to increase. Both plastics and other organic chemicals circulating in the environment such as polycyclic aromatic hydrocarbons (PAHs), dioxins, and pesticides like DDT are lipophilic, meaning that they have a high affinity for fats and oils [3]. These similar chemical properties facilitate the binding of these dangerous chemicals to sea plastics, and then the subsequent accumulation of these chemicals in the fats and oils in marine animals.

The fat-seeking nature of these plastics and chemicals also sadly means that instead of being carried safely out of the digestive track after being ingested, these chemicals accumulate in the body. The more plastic ingested, the more toxic chemicals, remain in that animal. This poses a serious risk for human health too, as we are near the top of the marine food chain. As smaller animals are consumed by larger ones, the concentration of these chemicals reaches their highest concentrations in large marine mammals and humans. Exposure to PCBs, pesticides, and other chemicals linked with micro-plastics is associated with cancer, developmental issues, impaired reproduction, and altered immune responses in animals and humans.

New research underscores the seriousness of the bio-accumulation of these chemicals. While it had previously been known that up to 70% of the marine garbage, including the highly common polyester fibers are denser than water and settle near bottom feeders like clams and muscles [4], this new research shows that the settled micro-plastics can enter bivalve mollusks and circulate in their blood stream. This is causing alarm because mollusks are at the bottom of the marine food chain [3], so it is now clear that micro-plastics have infiltrated every level of the marine ecosystem. Ultimately, this puts humans at an even a greater risk than ever before of ingesting high concentrations of pollutants in seafood.

Removing the plastic that already exists in the ocean is a massive technological challenge that needs to be addressed. For now, however, preventing the addition of new plastic in the ocean can serve as a significant and easier step protect the environment and spare humans from further chemical exposure. There are already a number of strategies in place to help limit the addition of more plastic to the Pacific Ocean. At the commercial level, products with micro-beads, particularly cosmetic, can be removed from the market. An international campaign composed of 69 non-governmental organizations across 33 countries, including ASEAN’s close neighbors of Australia and the Republic of Korean, is moving to ban micro-beads to protect the environment [7].

On the individual and national levels, we need to adopt the slogan of The International Pellet Watch, which monitors micro-plastics globally: No single-use plastic! [4]. Plastic consumption and waste need to decrease and the reuse and recycling of plastic needs to increase.

Within ASEAN, we already have global leaders in revolutionizing recycling. Singapore, for example, has taken an aggressive stance to prevent waste and to creatively reuse plastics. As a nation, Singapore is aiming to recycle 60% of their waste. Strategies to prevent plastic pollution can also extend beyond the government. One innovative example is Singapore and Indonesia-based Nevhouse. Nevhouse collects plastic wastes, recycles it into molded panels, which are then used to builds efficient, low-cost, prefab houses out of recycled plastic waste. The structures can be assembled in two to three days and are therefore ideal for use in poor or disaster-affected areas. Moreover, the final structures are fire and earthquake resistant.

ASEAN’s innovative strengths have already started to limit the damage we are doing to our oceans by preventing the addition of some plastics into the ocean. The need for more technical innovations to both prevent more plastic being added to the Giant Pacific Garbage Patch and to remove the plastic that is already putting our oceans in peril remains present.

 

Works Cited
[1] National Geographic Education. (2015, June) Great Pacific Garbage Patch. [Online]. http://education.nationalgeographic.com/education/encyclopedia/great-pacific-garbage-patch/?ar_a=1
[2] Smithsonian Institution. (2015, May) Ocean Trash Plaguing Our Sea. [Online]. http://ocean.si.edu/ocean-news/ocean-trash-plaguing-our-sea
[3] Nate Seltenrich, “New Link in the Food Chain? Marine Plastic Pollution and Seafood Safety,” Environmental Health Perspectives, vol. 123, no. 2, February 2015.
[4] Hideshige Takada. (2013, May) Microplastics and the Threat to Our Seafood. [Online]. http://www.oceanhealthindex.org/News/Microplastics
[5] Clare Leschin-Hoar, “Fleeced Again: How Microplastic Causes Macro Problems For the Ocean,” Grist, December 2011.
[6] N.M. Hall, K.L.E. Berry, L. Rintoul, and M.O. Hoogenboom, “Microplastic ingestion by scleractinian corals,” Marine Biology, vol. 162, no. 3, pp. 725-732, January 2015.
[7] International Campaign Against Microbeads in Cosmetics. (2015) International Campaign Against Microbeads in Cosmetics. [Online]. http://www.beatthemicrobead.org/en/in-short

 

 

About the Author: Holly Lauridsen is a graduate student in biomedical engineering at Yale University, where she is conducting research on inflammation and vascular health. She is participating in the United States Virtual Foreign Service internship with the US Mission to ASEAN. She is originally from Portland, Oregon. Follow Holly on Twitter @HollysSciFinds to learn more about exciting new science!