Trash Islands

Garbage Patches in the Atlantic and Pacific Oceans

Trash on a beach in Thailand.
Utopia_88 / Getty Images

As our global population expands, so does the amount of trash we produce, and a large portion of that trash ends up in the world's oceans. Due to oceanic currents, much of the trash is carried to areas where the currents meet, and these collections of trash have recently been referred to as marine trash islands.

Contrary to common belief, most of these trash islands are almost invisible to the eye. There are a few patches around the world where trash accumulates into platforms of 15-300 feet large, often near certain coasts, but they are minuscule compared to the vast garbage patches located in the middle of oceans.

These are predominantly composed of microscopic plastic particles and not easily spotted. In order to identify their actual size and density, a lot of research and testing needs to be done.

The Great Pacific Garbage Patch

The Great Pacific Garbage Patch—sometimes called the Eastern Garbage Patch or Eastern Pacific Trash Vortex—is an area with an intense concentration of marine trash located between Hawaii and California. The exact size of the patch is unknown, however, because it is constantly growing and moving.

The patch developed in this area because of the North Pacific Subtropical Gyre—one of many oceanic gyres caused by a convergence of ocean currents and wind. As the currents meet, the earth’s Coriolis Effect (the deflection of moving objects caused by the Earth’s rotation) causes the water to slowly rotate, creating a funnel for anything in the water.

Because this is a subtropical gyre in the northern hemisphere, it rotates clockwise. It’s also a high-pressure zone with hot equatorial air and comprises much of the area known as the horse latitudes (area with weak winds).

Due to the tendency of items to collect in oceanic gyres, the existence of a garbage patch was predicted in 1988 by the National Oceanic and Atmospheric Association (NOAA) after years of monitoring the amount of trash being dumped into the world's oceans.

The patch was not officially discovered until 1997, though, because of its remote location and harsh conditions for navigation. That year, Captain Charles Moore passed through the area after competing in a sailing race and discovered debris floating over the entire area he was crossing.

Atlantic and Other Oceanic Trash Islands

Though the Great Pacific Garbage Patch is the most widely publicized of the so-called trash islands, the Atlantic Ocean has one as well in the Sargasso Sea.

The Sargasso Sea is located in the North Atlantic Ocean between 70 and 40 degrees west longitude and 25 and 35 degrees north latitude. It is bounded by the Gulf Stream, the North Atlantic Current, the Canary Current, and the North Atlantic Equatorial current.

Like the currents carrying trash into the Great Pacific Garbage Patch, these four currents carry a portion of the world's trash to the middle of the Sargasso Sea where it becomes trapped.

In addition to the Great Pacific Garbage Patch and the Sargasso Sea, there are three other major tropical oceanic gyres in the world—all with conditions similar to those found in these first two.

Components of Trash Islands

After studying the trash found in the Great Pacific Garbage Patch, Moore learned that 90% of the trash found there was plastic. His research group, as well as NOAA, has studied the Sargasso Sea and other patches around the world and their studies in those locations have had the same findings.

It is typically thought that 80% of the plastic in the ocean comes from land sources while 20% comes from ships at sea. A 2019 study contests that "there is little evidence to support this assumption." Instead, it is more likely that most of the trash comes from merchant ships.

The plastics in the patches consist of all sorts of plastic items—not only water bottles, cups, bottle caps, toothbrushes, or plastic bags, but also materials used on cargo ships and fishing fleets—nets, buoys, ropes, crates, barrels, or fish netting (which alone constitute up to 50% of the entire ocean plastic).


It’s not just large plastic items that make up the trash islands, however. In his studies, Moore found that the majority of the plastic in the world's oceans is made up of billions of pounds of microplastic—raw plastic pellets called nurdles. These pellets are a byproduct of plastics manufacturing and of photodegradation—process during which materials (in this case plastic) break apart into smaller pieces due to sunlight and air (but don't disappear).

It is significant that most of the trash is plastic because plastic does not break down easily—especially in water. When plastic is on land, it is more easily heated and breaks down faster. In the ocean, the plastic is cooled by the water and becomes coated with algae which shield it from sunlight.

Because of these factors, the plastic in the world’s oceans will last well into the future. For example, the oldest plastic container found during the 2019 expedition turned out to be from 1971—48 years old.

What is also significant is the microscopic size of the majority of the plastic in the waters. Because of its invisibility to the naked eye, it is very complicated to measure the actual amount of plastic in the oceans, and it is even more difficult to find non-invasive ways of cleaning it up. This is why the most frequent strategies of caring for our oceans involve prevention.

Another major issue with the ocean trash being mainly microscopic is the effect it has on wildlife and consequently on humans.

Garbage Islands' Impact on Wildlife and Humans

The presence of the plastic in the garbage patches is having a significant impact on wildlife in a number of ways. Whales, seabirds, and other animals can easily be snared in the nylon nets and six-pack rings prevalent in the garbage patches. They are also in danger of choking on things like balloons, straws, and sandwich wrap.

Additionally, fish, seabirds, jellyfish, and oceanic filter feeders easily mistake brightly colored plastic pellets for fish eggs and krill. Research has shown that over time, the plastic pellets can concentrate toxins which are passed on to sea animals when they eat them. This could poison them or cause genetic problems.

Once the toxins are concentrated in the tissue of one animal, they can magnify across the food chain similar to the pesticide DDT and eventually reach humans as well. It is likely that shellfish and dried fish will be the first major carriers of microplastics (and the toxins associated with them) into humans.

Finally, the floating trash can also aid in the spread of species to new habitats. Take, for instance, a type of barnacle. It can attach to a floating plastic bottle, grow, and move to an area where it is not naturally found. The arrival of the new barnacle could then possibly cause problems for the area's native species.

The Future for the Trash Islands

Research conducted by Moore, NOAA, and other agencies show that trash islands are continuing to grow. Attempts have been made to clean them up but there is simply too much material over too large of an area to make any significant impact.

Ocean cleanup is similar to invasive surgery, as microplastic blends so easily with marine life. Even if thorough cleanup was possible, many species and their habitats would be deeply affected, and this is highly controversial.

Therefore, some of the best ways to aid in the cleanup of these islands are to suppress their growth by changing our relationship with plastic. It means enacting stronger recycling and disposal policies, cleaning up the world's beaches, and reducing the amount of trash going into the world's oceans.

Algalita, the organization founded by Captain Charles Moore, strives to make the change through vast educational programs all over the world. Their motto is: "Refuse, Reduce, Reuse, Repurpose, Recycle. In that order!"


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Briney, Amanda. "Trash Islands." ThoughtCo, Dec. 6, 2021, Briney, Amanda. (2021, December 6). Trash Islands. Retrieved from Briney, Amanda. "Trash Islands." ThoughtCo. (accessed February 6, 2023).