The area of increased plastic particles is located within the North Pacific Gyre, one of the five major ocean gyres.
The Great Pacific garbage patch, also described as the Pacific trash vortex, is a gyre of marine debris particles in the north central Pacific Ocean. It is located roughly from 135°W to 155°W and 35°N to 42°N. The collection of plastic and floating trash, which comes primarily from countries in Asia, lies halfway between Hawaii and California
and extends over an indeterminate area of widely varying range,
depending on the degree of characterized by exceptionally high relative
pelagic concentrations of plastic, chemical sludge, and other debris that have been trapped by the currents of the North Pacific Gyre.
Despite the common public image of islands of floating rubbish, its low
density (4 particles per cubic meter) prevents detection by satellite imagery,
or even by casual boaters or divers in the area. It consists primarily
of an increase in suspended, often microscopic, particles in the upper water column.
The patch is not easily seen from the sky, because the plastic is dispersed over a large area. Researchers from The Ocean Cleanup
project claimed that the patch covers 1.6 million square kilometers.
The plastic concentration is estimated to be up to 100 kilograms per
square kilometer in the center, going down to 10 kilograms per square
kilometer in the outer parts of the patch. An estimated 80,000 metric
tons of plastic inhabit the patch, totaling 1.8 trillion pieces. 92% of
the mass in the patch comes from objects larger than 0.5 centimeters.
Research indicates that the patch is rapidly accumulating. A similar patch of floating plastic debris is found in the Atlantic Ocean, called the North Atlantic garbage patch.
History
The patch is created in the gyre of the North Pacific Subtropical Convergence Zone.
The patch was described in a 1988 paper published by the National Oceanic and Atmospheric Administration (NOAA). The description was based on research by several Alaska-based researchers in 1988 who measured neustonic plastic in the North Pacific Ocean.
Researchers found relatively high concentrations of marine debris
accumulating in regions governed by ocean currents. Extrapolating from
findings in the Sea of Korea,
the researchers hypothesized that similar conditions would occur in
other parts of the Pacific where prevailing currents were favorable to
the creation of relatively stable waters. They specifically indicated
the North Pacific Gyre.
Charles J. Moore, returning home through the North Pacific Gyre after competing in the Transpacific Yacht Race in 1997, claimed to have come upon an enormous stretch of floating debris. Moore alerted the oceanographer Curtis Ebbesmeyer, who subsequently dubbed the region the "Eastern Garbage Patch" (EGP). The area is frequently featured in media reports as an exceptional example of marine pollution.
The JUNK Raft Project was a 2008 trans-Pacific sailing voyage made to highlight the plastic in the patch, organized by the Algalita Marine Research Foundation.
In 2009, two project vessels from Project Kaisei, the New Horizon and the Kaisei, embarked on a voyage to research the patch and determine the feasibility of commercial scale collection and recycling. The 2009 SEAPLEX expedition also researched the patch. Researchers were also looking at the impact of plastic on mesopelagic fish, such as lanternfish.
At TEDxDelft2012, Boyan Slat unveiled a concept for removing large amounts of marine debris from oceanic gyres. Calling his project The Ocean Cleanup,
he proposed to use surface currents to let debris drift to collection
platforms. Operating costs would be relatively modest and the operation
would be so efficient that it might even be profitable. The concept
makes use of floating booms that divert rather than catch the debris.
This avoids bycatch,
while collecting even the smallest particles. According to Slat's
calculations, a gyre could be cleaned up in five years' time, amounting
to at least 7.25 million tons of plastic across all gyres. He also advocated "radical plastic pollution prevention methods" to prevent gyres from reforming. In 2015, The Ocean Cleanup project was a category winner in the Design Museum's 2015 Designs of the Year awards.
A fleet of 30 vessels, including a 32-metre (105-foot) mothership, took
part in a month-long voyage to determine how much plastic is present
using trawls and aerial surveys.
The 2012 Algalita/5 Gyres Asia Pacific Expedition began in the Marshall Islands
on 1 May, investigated the patch, collecting samples for the 5 Gyres
Institute, Algalita Marine Research Foundation and several other
institutions, including NOAA, Scripps, IPRC and Woods Hole Oceanographic Institute.
In 2012, the Sea Education Association (SEA) conducted research
expeditions in the gyre. 118 net tows were conducted and nearly 70,000
pieces of plastic were counted.
In 2012, researchers Goldstein, Rosenberg and Cheng found that
microplastic concentrations in the gyre had increased by two orders of
magnitude in the prior four decades.
On 11 April 2013, artist Maria Cristina Finucci founded The Garbage Patch State at UNESCO—Paris in front of Director General Irina Bokova.
In 2015, a study published in the journal Science
sought to discover where exactly all of this garbage is coming from.
According to the researchers, the discarded plastics and other debris
floats eastward out of countries in Asia from six primary sources:
China, Indonesia, the Philippines, Vietnam, Sri Lanka and Thailand.
On 9 September 2018, the first collection system was deployed to the gyre to begin the collection task. This initial trial run of the Ocean Cleanup Project started towing its "Ocean Cleanup System 001" from San Francisco to a trial site some 240 nautical miles (260 miles) away.
Constitution
The north Pacific Garbage Patch on a continuous ocean map
The Great Pacific garbage patch formed gradually as a result of ocean or marine pollution gathered by ocean currents. It occupies a relatively stationary region of the North Pacific Ocean bounded by the North Pacific Gyre in the horse latitudes.
The gyre's rotational pattern draws in waste material from across the
North Pacific, including coastal waters off North America and Japan. As
material is captured in the currents, wind-driven surface currents
gradually move debris toward the center, trapping it.
No strong scientific data concerning the origins of pelagic plastics exists. In a 2014 study
researchers sampled 1571 locations throughout the world's oceans, and
determined that discarded fishing gear such as buoys, lines and nets
accounted for more than 60% of the mass of plastic marine debris. According to a 2011 EPA
report, "The primary source of marine debris is the improper waste
disposal or management of trash and manufacturing products, including
plastics (e.g., littering, illegal dumping) ... Debris is generated on
land at marinas, ports, rivers, harbors, docks, and storm drains. Debris
is generated at sea from fishing vessels, stationary platforms, and
cargo ships." Constituents range in size from miles-long abandoned fishing nets to micro-pellets used in cosmetics and abrasive cleaners. Currents carry debris from the west coast of North America to the gyre in about six years, and from the east coast of Asia in a year or less.
A 2017 study concluded that of the 9.1 billion tons of plastic
produced since 1950, close to 7 billion tons are no longer in use. The authors estimate that 9% was recycled, 12% was incinerated, and the remaining 5.5 billion tons remains in the oceans and land.
Size estimates
The size of the patch is indefinite, as is the precise distribution of debris, because large items are uncommon.
Most debris consists of small plastic particles suspended at or just
below the surface, evading detection 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)
(about the size of Texas) to more than 15,000,000 square kilometres
(5,800,000 sq mi) (about the size of Russia). Such estimates, however,
are conjectural given the complexities of sampling and the need to
assess findings against other areas. Further, although the size of the
patch is determined by a higher-than-normal degree of concentration of
pelagic debris, there is no standard for determining the boundary
between "normal" and "elevated" levels of pollutants to provide a firm
estimate of the affected area.
Net-based surveys are less subjective than direct observations but are limited regarding the area that can be sampled (net apertures 1–2 m and ships typically have to slow down to deploy nets, requiring dedicated ship's time). The plastic debris sampled is determined by net mesh size, with similar mesh sizes required to make meaningful comparisons among studies. Floating debris typically is sampled with a neuston or manta trawl net lined with 0.33 mm mesh. Given the very high level of spatial clumping in marine litter, large numbers of net tows are required to adequately characterize the average abundance of litter at sea. Long-term changes in plastic meso-litter have been reported using surface net tows: in the North Pacific Subtropical Gyre in 1999, plastic abundance was 335,000 items/km2 and 5.1 kg/km2, roughly an order of magnitude greater than samples collected in the 1980s. Similar dramatic increases in plastic debris have been reported off Japan. However, caution is needed in interpreting such findings, because of the problems of extreme spatial heterogeneity, and the need to compare samples from equivalent water masses, which is to say that, if an examination of the same parcel of water a week apart is conducted, an order of magnitude change in plastic concentration could be observed.
— Ryan et al
In August 2009, the Scripps Institution of Oceanography/Project Kaisei
SEAPLEX survey mission of the Gyre found that plastic debris was
present in 100 consecutive samples taken at varying depths and net sizes
along a path of 1,700 miles (2,700 km) through the patch. The survey
found that, although the patch contains large pieces, it is on the whole
made up of smaller items that increase in concentration toward the
gyre's centre, and these 'confetti-like' pieces that are visible just beneath the surface suggests the affected area may be much smaller. 2009 data collected from Pacific albatross populations suggest the presence of two distinct debris zones.
In March 2018, The Ocean Cleanup
published a paper summarizing their findings from the Mega- (2015) and
Aerial Expedition (2016). In 2015, the organization crossed the Great
Pacific garbage patch with 30 vessels, to make observations and take
samples with 652 survey nets. They collected a total of 1.2 million
pieces, which they counted and categorized into their respective size
classes. In order to also account for the larger, but more rare larger
debris, they also overflew the patch in 2016 with a C-130 Hercules aircraft, equipped with LiDAR sensors.
The findings from the two expeditions, found that the patch covers 1.6
million square kilometers with a concentration of 10–100 kg per square
kilometer. They estimate an 80,000 metric tons in the patch, with 1.8
trillion plastic pieces, out of which 92% of the mass is to be found in
objects larger than 0.5 centimeters.
NOAA stated:
While "Great Pacific Garbage Patch" is a term often used by the media, it does not paint an accurate picture of the marine debris problem in the North Pacific Ocean. The name "Pacific Garbage Patch" has led many to believe that this area is a large and continuous patch of easily visible marine debris items such as bottles and other litter—akin to a literal island of trash that should be visible with satellite or aerial photographs. This is not the case.
— Ocean Facts, National Ocean Service
Photodegradation of plastics
Washed-up plastic waste on a beach in Singapore
The patch is one of several oceanic regions where researchers have studied the effects and impact of plastic photodegradation in the neustonic layer of water. Unlike organic debris, which biodegrades, plastic disintegrates into ever smaller pieces while remaining a polymer (without changing chemically). This process continues down to the molecular level. Some plastics decompose within a year of entering the water, releasing potentially toxic chemicals such as bisphenol A, PCBs and derivatives of polystyrene. As the plastic flotsam
photodegrades into smaller and smaller pieces, it concentrates in the
upper water column. As it disintegrates, the pieces become small enough
to be ingested by aquatic organisms that reside near the ocean's
surface. Plastic may become concentrated in neuston, thereby entering the food chain.
Disintegration means that much of the plastic is too small to be seen. In a 2001 study, researchers found concentrations of plastic particles at 334,721 pieces per km2 with a mean mass of 5.1 kg (11.3 lbs) per km2, in the neuston. The overall concentration of plastics was seven times greater than the concentration of zooplankton
in many of the sampled areas. Samples collected deeper in the water
column found much lower concentrations of plastic particles (primarily monofilament fishing line pieces).
Effect on marine life and humans
NOAA's marine debris removal in 2014
The United Nations Ocean Conference estimated that the oceans might contain more weight in plastics than fish by the year 2050. Some long-lasting plastics end up in the stomachs of marine animals.
Plastic attracts seabirds and fish. When marine life consumes plastic
allowing it to enter the food chain, this can lead to greater problems
when species that have consumed plastic are then eaten by other
predators.
Animals can also become trapped in plastic nets and rings, which can cause death. Sea turtles are most affected by this. Cetaceans
have been sighted within the patch, which poses entanglement and
ingestion risks to animals using the Great Pacific garbage patch as a
migration corridor or core habitat.
Affected species include sea turtles and the black-footed albatross. Midway Atoll receives substantial amounts of marine debris from the patch.
Direct harm to species
Of the 1.5 million Laysan albatrosses that inhabit Midway Atoll, nearly all are likely to have plastic in their gastrointestinal tract.
Approximately one-third of their chicks die, and many of those deaths
are from plastic unwittingly fed to them by their parents. Twenty tons of plastic debris washes up on Midway every year with five tons ending up in the bellies of albatross chicks. Fish and whales may also mistake the plastic as a food source.
Indirect harm via the food chain
On the microscopic level, debris can absorb organic pollutants from seawater, including PCBs, DDT and PAHs. Aside from toxic effects, some of these are mistaken by the endocrine system as estradiol, disrupting hormone levels in affected animals. These toxin-containing plastic pieces are also eaten by jellyfish, which are then eaten by fish and then by humans.
Spreading invasive species
Marine
plastics facilitate the spread of invasive species that attach to
floating plastic in one region and drift long distances to colonize
other ecosystems. Debris affects at least 267 species worldwide.
Increasing microplastic concentrations has released the insect Halob
