The Great Pacific Garbage Patch is a massive clump of plastic waste floating in the world’s largest ocean, but it isn’t the only one, and scientists are working to figure out how to clean it up.
Reach’s Penaflor is a man on a mission. Since 2009, he has worked with the River Warriors, an organization dedicated to cleaning up estuaries that feed into the Pasig River, which runs through the Philippines’ largest urban area, Metro Manila, and is notorious for its foul odors. The Pasig River, according to scientists, is the most responsible for polluting the marine environment.
When the clean-up first started, so much solid waste sat on top of the water that it had to be removed by hand; women volunteers waded into the polluted waters with little to no protective gear before dredging could begin. “They needed to dig deep to get things out, wearing nothing but gloves for protection,” Penaflor recalls. “I decided to work with them and could only last half a day. I couldn’t stop itching and I couldn’t get rid of the stench.”
Penaflor and those he works with are well aware of the Pasig River’s bad reputation, as well as the Sisyphean task of trying to change things. The Philippines generates more marine pollution than many other Asian countries, and, perhaps surprisingly, the majority of that garbage remains close to shore.
According to Britta Denise Hardesty, senior principal research scientist of the oceans and atmosphere for Australia’s national research body, the Commonwealth Scientific and Industrial Research Organisation (CSIRO), there are numerous misconceptions about the waste we see in the ocean. While we can see it floating in some places, ocean currents can sweep it out to sea, causing it to accumulate in distant plastic soups like the “Great Pacific Garbage Patch,” which sits between Hawaii and the west coast of the United States.
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The highly publicised Pacific Patch is only one of the gyres, or circulating ocean currents, that move in a never-ending circle around the world’s oceans. The gyres are part of the “ocean conveyor belt,” which is propelled by currents flowing across the ocean’s surface in a clockwise direction in the north and a counter-clockwise direction in the south. Because the currents behave like massive whirlpools, they end up pushing debris closer to the centre, where it can accumulate in greater concentrations due to reduced wind and wave action.
Plastic debris that does find its way into the open oceans can drift for years if it remains buoyant and can become a form of shelter for some sealife (Credit: Alamy)
According to Britta Baechler, senior manager of ocean plastic research at the environmental advocacy organisation Ocean Conservancy: “There are five major oceanic gyres in total. All five gyres are large systems of circular ocean currents that collect floating objects such as plastics; however, the North Pacific Gyre is the most studied of the oceanic gyres, with little known about the other four.” Others can be found in the South Pacific, North and South Atlantic, Indian Ocean, and a variety of smaller gyres.
“What is important to know or to note is that the majority of the plastic or waste that is lost into the environment does not end up in these garbage patches,” Hardesty says. “It does not go all the way out to sea. The majority of our debris ends up trapped in back shore vegetation on land.”
Indeed, the majority of the debris found in the ocean is already there; at least half of it comes from fishing trawlers passing through international waters, and includes lost or abandoned nets and fishing gear. Then there are items that were once part of ocean cargo but were lost at sea. The World Shipping Council estimates that an average of 1,382 containers are lost each year due to strong winds and high seas, but the number could be much higher because container losses aren’t reported unless the steel boxes that have been swept overboard are known to be transporting hazardous materials.
The gyres have become floating, soupy masses of microplastics as a result of ocean pollution.
More than 29,000 bathtub toys, including plastic ducks, turtles, frogs, and beavers, fell off the back of a cargo ship bound for the United States from China in 1992, becoming one of the most widely reported container losses of the twentieth century. These ducks later became famous after they began washing up on beaches across the United States, and they did so for more than two decades after the incident.
While this may appear to be good news, it is not entirely accurate. Hardesty adds that even if hundreds of tonnes of garbage end up in the ocean, buoyant items can still break through the littoral zone, which extends about 8km (5 miles) from the shore. From there, a combination of wind, current, and waves can break down garbage and transport it thousands of miles from its original location.
“We know, for example, that items moved from Japan to the west coast of the United States in less than a year after the  tsunami blew large objects like motorcycles and floating docks across the Pacific Ocean in a year, or two years,” she says.
The most buoyant objects caught up in ocean currents can eventually end up in the Great Pacific Garbage Patch, which was first proposed in 1997 by oceanographer Curtis Ebbesmeyer. He had spent decades researching and tracking ocean debris, and he was the one who called the patch one of the planet’s “most important geological features.”
Drifting plastics degrade into smaller microplastics, which have been found in sand on beaches worldwide.
Because of ocean pollution, the gyres have turned into floating, soupy masses of microplastics, the result of the physical breakdown that begins as soon as plastic enters the sea. While heavier organic materials like wood and metal may eventually degrade or sink to the bottom, plastic degrades near the surface as a physical reaction to abrasion, prolonged UV exposure, and degradation from prolonged contact with water. Microplastics are created when larger pieces of plastic break down into smaller chunks or pieces as a result of exposure to physical forces such as wind or waves. According to studies, these pieces can be as small as a third of a millimetre in size and account for up to 60% of the floating plastic debris in the North Pacific Gyre.
However, it is unknown how much plastic ends up accumulating within the gyres’ centres. The Algalita Marine Research Foundation explored the South Pacific between 2016 and 2017, collecting samples from the South Pacific Subtropical Gyre and discovering what they thought were high concentrations of plastic fragments, but the quantities were not disclosed. However, they could not be certain that these concentrations were above normal levels; they have requested additional data to address what could be significant errors in estimates of the amount of global plastic now found in the ocean. Prior to that study, in 2014, it was thought that the gyres only had 200 to 600g (7 to 21 oz) of plastic litter per square kilometre.