Updated: Jan 20, 2021
By Talia Chen
Art retrieved from Bonnie Monteleone.
What are ocean garbage patches?
They’re extensive amounts of broken down trash that accumulate in gyres—systems of circulating currents like slow whirlpools. The center of a gyre is stable, and its currents will corral pollution into it, collecting bits and pieces of pollution that will endanger sea life and potentially harm traveling vessels. A common misconception is that these accumulations of trash are obvious, resembling a bob-for-apples bin: the litter is easy to spot and easy to scoop up. While this can be true, garbage patches mainly consist of a lot of partially degraded pollution a.k.a. marine debris, making it hard to gauge how large a garbage patch really is, and making it immensely difficult to clean. On average, 80% of marine debris comes from the coasts and another 20% comes from boats (varies by region). Plastics make up a large portion of pollution due to durability and malleability, as well as high usage in products. Although microplastics (pieces of plastic litter) are minuscule, they still take a long time to decompose, posing a threat to marine life.
The largest of these patches is the Great Pacific Garbage patch, located in the North Pacific Gyre in between Hawaii and California. This patch is mostly plastic debris, and is also called the Pacific Trash Vortex. Scientists predicted its existence, however it was discovered and named by racing boat captain Charles Moore, who found it while sailing from Hawaii to California after a yacht race. There is no exact size of the Pacific Trash Vortex because microplastics could fill the water for any number of miles beyond the chunkier accumulations of trash. It’s also difficult (or near impossible) to measure its size because the trash extends underwater and the gyre is huge, so it can’t be assumed that the gyre perfectly encapsulates the garbage patch. A National Geographic article stated that “oceanographers and ecologists also recently discovered that around 70% of marine debris sinks to the bottom of the ocean, creating the possibility that the Great Pacific Garbage Patch could also be an underwater accumulation of trash.” The same article also referenced a 2018 study shows that synthetic fishing nets make up about half of this specific patch due to an increase of fishing in the Pacific.
The North Pacific Gyre has another large patch of pollution: the Western Garbage Patch, located in the South Pacific. The two Pacific patches are linked together by the North Pacific Subtropical Convergence Zone, where the warm water of the South Pacific meets the cooler water from the Arctic. The convergence zone moves the trash in between patches.
Like the Pacific Trash Vortex and its southern counterpart, the largest garbage patches are located within the five most impactful gyres of the ocean: the North Atlantic Gyre, the South Atlantic Gyre, the North Pacific Gyre, the South Pacific Gyre, and the Indian Ocean Gyre. These aren’t the only garbage patches out there since any accumulation of ocean pollution forms a garbage patch, and there are minor gyres that don’t affect the currents as much, which means there are actually a lot of garbage patches in the ocean, only smaller.
Ocean debris is mostly microplastics because plastic breaks down over long periods of time. There are many types of plastic due to the existence of a variety of sources. Some start small like microbeads in face-wash but other larger pieces are just broken down over and over again by waves, storms, and other elements such as photo-degradation, which degrades plastics, releasing its chemicals into aquatic ecosystems. It is also important to differentiate between biodegradable plastics and bioplastics, and to understand that these materials won’t resolve the issue of garbage patches. A Columbia University article explains that while bioplastics are (sustainably) made from substances like vegetable oils, they act like normal fossil fuel plastics in decomposition. Biodegradable plastic breaks down faster, but a shorter degradation time doesn’t mean they’re any less dangerous for marine life since it’s still present in the ocean and releasing chemicals. Both types of plastic are a significant improvement, however they don’t actually solve the problem. A scholarly article about ocean plastic pollution solutions in the UK explained that “there is no balance of scientific proof to show that biodegradable plastics reduce the risks posed by marine litter”. A good amount of marine life consumes microplastic, which contains chemicals and could absorb other toxic chemicals that are floating in the ocean. Plastics can leach and absorb pollutants such as bisphenol A (BPA), that have been linked to health/environmental problems. Aquatic birds such as albatrosses will try to eat pollution and feed it to babies, in which the chicks will die of starvation or rupture their organs. Marine life also gets caught in discarded nets - an occurrence called ghost fishing - and mammals will drown if they are unable to escape the net.
The plastic also blocks sunlight which prevents plankton/algae from feeding and growing. This harms ecosystems because plankton and algae are the most common autotrophs (they can produce their own nutrients) in the food web. Algae and plankton are vital to food chains. In addition, drifting debris can transport species to different areas, introducing invasive species such as barnacles or mussels to different ocean habitats.
There is concern that humans are ingesting microplastics through seafood and salt, and researchers are actively exploring this topic. Marine debris also poses a potential problem for navigation and vessels, for example, pollution getting caught in a ship’s propellers. As previously mentioned, garbage patches are hard to clean up because of their size. One of NOAA’s (National Ocean and Atmospheric Administration) podcasts reported that “if you tried to clean up less than one percent of the North Pacific Ocean it would take 67 ships one year”. Even if pollution was cleared up, debris would continue entering the oceans due to the amount of plastic we use. One podcaster described beach pollution as “Bottles, bags, aerosol cans, all mixed together. In some places it's like a thick mat … For example, I was on a beach in Lanai in Hawaii and we found everything from plastic bottles to flip flops, fishing gear, we found an entire couch. And some of this debris was clearly local and some of it had clearly come from other countries around the Pacific Rim. So debris can touch even the most remote places”. Just clearing up marine debris would cost a huge amount of money, so who would pay for it? The logistics of clearing ocean pollution is up for question as well, with microplastics being the same size as small sea creatures, ruling out any form of a net. Larger debris can be picked out, but microplastics are a challenge.
It might not be possible to completely demolish patches, but prevention is a good start and a way to stop further growth. Recycling more plastic, beach cleanups, and stopping the use of plastic microbeads, are good ways to approach this with source reduction and efficient waste management being the ultimate goal. The bottom line, as stated in the National Geographic article, is that scientists and explorers agree that the best thing to do is limit/stop plastic use and use eco-friendly materials. The deterioration of oceans that is encapsulated in these huge patches of pollution adds to the list of reasons calling for sustainability on a larger scale. As individuals, we can do our part by recycling plastic when possible and looking for eco-friendliness in the products we use.
Written by writer Talia Chen