8th Continent: The Great Pacific Garbage Patch

The Great Pacific Garbage Patch, also described as the Pacific Trash Vortex, is a gyre of marine litter in the central North Pacific Ocean located roughly between 135°W to 155°W and 35°N and 42°N.The patch extends over an indeterminate area, with estimates ranging very widely depending on the degree of plastic concentration used to define the affected area.

The Patch is characterized by exceptionally high concentrations of pelagic plastics, chemical sludge, and other debris that have been trapped by the currents of the North Pacific Gyre. Despite its size and density, the patch is not visible from satellite photography, since it consists primarily of suspended particulates in the upper water column. Since plastics break down to even smaller polymers, concentrations of submerged particles are not visible from space, nor do they appear as a continuous debris field. Instead, the patch is defined as an area in which the mass of plastic debris in the upper water column is significantly higher than average.


It is thought that, like other areas of concentrated marine debris in the world's oceans, the Great Pacific Garbage Patch formed gradually as a result of marine pollution gathered by oceanic currents. The garbage patch occupies a large and relatively stationary region of the North Pacific Ocean bound by the North Pacific Gyre (a remote area commonly referred to as the horse latitudes). The gyre's rotational pattern draws in waste material from across the North Pacific Ocean, including coastal waters off North America and Japan. As material is captured in the currents, wind-driven surface currents gradually move floating debris toward the center, trapping it in the region.

The size of the patch is unknown, as large items readily visible from a boat deck are uncommon. Most debris consists of small plastic particles suspended at or just below the surface, making it impossible to detect by aircraft or satellite. Instead, the size of the patch is determined by sampling. Estimates of size range from 700,000 square kilometres (270,000 sq mi) to more than 15,000,000 square kilometres (5,800,000 sq mi) (0.41% to 8.1% of the size of the Pacific Ocean), or, in some media reports, up to "twice the size of the continental United States".Such estimates, however, are conjectural based on the complexities of sampling and the need to assess findings against other areas.

Some of these long-lasting plastics end up in the stomachs of marine birds and animals, and their young,including sea turtles and the Black-footed Albatross. Midway Atoll receives substantial amounts of marine debris from the Great Pacific Garbage Patch. Of the 1.5 million Laysan Albatrosses that inhabit Midway, nearly all are found to have plastic in their digestive system.Of the approximately one-third of the chicks that die, many of them are due to being fed plastic from their parents.

Besides the particles' danger to wildlife, on the microscopic level the floating debris can absorb organic pollutants from seawater, including PCBs, DDT, and PAHs. Aside from toxic effects,when ingested, some of these are mistaken by the endocrine system as estradiol, causing hormone disruption in the affected animal. These toxin-containing plastic pieces are also eaten by jellyfish, which are then eaten by larger fish.

Many of these fish are then consumed by humans, resulting in their ingestion of toxic chemicals.Marine plastics also facilitate the spread of invasive species that attach to floating plastic in one region and drift long distances to colonize other ecosystems.

On the macroscopic level, the physical size of the plastic kills birds and turtles as the animals' digestion can not break down the plastic inside their stomachs. A second effect of the macroscopic plastic is to make it much more difficult for animals to see and detect their normal sources of food.Research has shown that this plastic marine debris affects at least 267 species worldwide and a few of the 267 species reside in the North Pacific Gyre.

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