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===Sources of pollutants===
===Sources of pollutants===
An estimated 80% of the garbage comes from land-based sources, and 20% from ships. A typical 3,000 passenger cruise ship produces over eight tons of solid waste weekly, much of which ends up in the patch.<ref>Clemmitt, Marcia. "New Rules Sought for 'Floating Cities.'" Saving the Oceans 15.39 (4 Nov. 2005): n. pag. CQ Researcher Online. Web. 5 Oct. 2009. <http://library.cqpress.com/cqresearcher/document.php?id=cqresrre2005110420&type=hitlist>.</ref> Pollutants range in size from abandoned fishing nets to micro-pellets used in abrasive cleaners.<ref name="sierra">{{Citation
There is no strong scientific data concerning the origins of pelagic plastics. The figure that an estimated 80% of the garbage comes from land-based sources and 20% from ships, is derived from on an unsubstantiated estimate.<ref>See Moore 2004</ref>However, ship-generated pollution is a source of concern since a typical 3,000 passenger cruise ship produces over eight tons of solid waste weekly, much of which ends up in the patch.<ref>Clemmitt, Marcia. "New Rules Sought for 'Floating Cities.'" Saving the Oceans 15.39 (4 Nov. 2005): n. pag. CQ Researcher Online. Web. 5 Oct. 2009. <http://library.cqpress.com/cqresearcher/document.php?id=cqresrre2005110420&type=hitlist>.</ref> Pollutants range in size from abandoned fishing nets to micro-pellets used in abrasive cleaners.<ref name="sierra">{{Citation
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Revision as of 14:02, 1 April 2010

Map showing the oceans' five major gyres
The Garbage Patch is located within the North Pacific Gyre, one of the five major oceanic gyres.

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° to 155°W and 35° to 42°N.[1] Although many scientists suggest that the patch extends over a very wide area, with estimates ranging from an area the size of the state of Texas to one larger than the continental United States, the exact size is unknown.[2] Recent data collected from Pacific albatross populations suggest there may be two distinct zones of concentrated debris in the Pacific.[3]

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.[4] Despite its size and density, the patch is not visible from satellite photography since it primarily consists of suspended particulate in the upper water column. Since plastics break down to ever smaller polymers, concentrated particulate is not visible from space, nor appears 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.

Discovery

Map showing large-scale looping water movements within the Pacific. One circles west to Australia, then south and back to Latin America. Further north, water moves east to Central America, and then joins a larger movement further north which loops south, west, north and east between North America and Japan. Two smaller loops circle in the eastern and central North Pacific.
The Patch is created in the gyre of the North Pacific Subtropical Convergence Zone

The existence of the Great Pacific Garbage Patch was predicted in a 1988 paper published by the National Oceanic and Atmospheric Administration (NOAA) of the United States. The prediction was based on results obtained by several Alaska-based researchers between 1985 and 1988 that measured neustonic plastic in the North Pacific Ocean.[5] This research found high concentrations of marine debris accumulating in regions governed by particular patterns of ocean currents. Extrapolating from findings in the Sea of Japan, 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.[6]

Charles J. Moore, returning home through the North Pacific Gyre after competing in the Transpac sailing race in 1997, came upon an enormous stretch of floating debris. Moore alerted the oceanographer Curtis Ebbesmeyer, who subsequently dubbed the region the "Eastern Garbage Patch" (EGP).[7] The area is frequently featured in media reports as an exceptional example of marine pollution.[8]. Moore's claim of having discovered a large, visible debris field is, however, a mischaracterization of the polluted region overall, since it primarily consists of particles that are generally invisible to the naked eye.[9]

A similar patch of floating plastic debris is found in the Atlantic Ocean.[10][11]

Formation

Map of gyres centered near the south pole (click to enlarge)
The north Pacific Garbage Patch on a continuous ocean map

Like other areas of concentrated marine debris in the world's oceans, it is thought, the Great Pacific Garbage Patch formed gradually as a result of marine pollution gathered by oceanic currents.[12] 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 on 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".[13] Such estimates, however, are conjectural based on the complexities of sampling and the need to assess findings against other areas.

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.[14]

Further, although the size of the patch is determined by a higher-than-normal degree of concentration of pelagic debris, there is no specific standard for determining the boundary between the "normal" and "elevated" levels of pollutants to provide a firm estimate of the affected area.

In August 2009, the Scripps Institute / 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 1,700 miles (2,700 km) path through the patch. The survey also confirmed that while the debris field does contain large pieces, it is on the whole made up of smaller items which increase in concentration towards the Gyre's centre, and these 'confetti-like' pieces are clearly visible just beneath the surface.

Sources of pollutants

There is no strong scientific data concerning the origins of pelagic plastics. The figure that an estimated 80% of the garbage comes from land-based sources and 20% from ships, is derived from on an unsubstantiated estimate.[15]However, ship-generated pollution is a source of concern since a typical 3,000 passenger cruise ship produces over eight tons of solid waste weekly, much of which ends up in the patch.[16] Pollutants range in size from abandoned fishing nets to micro-pellets used in abrasive cleaners.[17] Currents carry debris from the west coast of North America to the gyre in about five years, and debris from the east coast of Asia in a year or less.[18][19] An international research project led by Dr. Hideshige Takada of Tokyo University studying plastic pellets, or nurdles, from beaches around the world may provide further clues about the origins of pelagic plastic.[20]

Plastic photodegradation in the ocean

Main article: Photodegradation

The Great Pacific Garbage Patch has one of the highest levels known of plastic particulate suspended in the upper water column. As a result, it is one of several oceanic regions where researchers have studied the effects and impact of plastic photodegradation in the neustonic layer of water.[21] Unlike debris which biodegrades, the photodegraded plastic disintegrates into ever smaller pieces while remaining a polymer. This process continues down to the molecular level.[22]

As the plastic flotsam photodegrades into smaller and smaller pieces, it concentrates in the upper water column. As it disintegrates, the plastic ultimately becomes small enough to be ingested by aquatic organisms which reside near the ocean's surface. Plastic waste thus enters the food chain through its concentration in the neuston.

Some plastics decompose within a year of entering the water, leaching potentially toxic chemicals such as bisphenol A, PCBs and derivatives of polystyrene.[23]

Density of neustonic plastics

The patch is not a visibly dense field of floating debris. The process of disintegration means that the plastic particulate in much of the affected region is too small to be seen. Researchers must estimate the patch's overall extent and debris density from samples. In a 2001 study, researchers (including Moore) found concentrations of plastics at 334,721 pieces per km2 with a mean mass of 5,114 grams (11.27 lbs) per km2. Assuming each particle of plastic averaged 5 mm x 5 mm, this would amount to only 8m2 per km2. In many areas the overall concentration of plastics was seven-fold greater than the concentration of zooplankton. Samples collected at deeper points in the water column found much lower levels of debris (primarily monofilament fishing line), confirming earlier observations that most plastic waste concentrates in the upper water column.[24]

Effect on wildlife

The remains of a Laysan Albatross chick which was fed plastic by its parents resulting in death

Some of these long-lasting plastics end up in the stomachs of marine birds and animals, and their young,[7] including sea turtles, and the Black-footed Albatross.[25] Besides the particles' danger to wildlife, the floating debris can absorb organic pollutants from seawater, including PCBs, DDT, and PAHs.[26] Aside from toxic effects,[27] when ingested, some of these are mistaken by the endocrine system as estradiol, causing hormone disruption in the affected animal.[25] 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.[28] 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.[17]

Flotsam microhabitat

On the other hand there are certain species of algae, crustaceans and fish that thrive on the microhabitat provided by floating junk. Certain flotsam fishes, like the ocean triggerfish (Canthidermis), spend their larval or juvenile stage in the ocean and seek for flotsam thereafter.[29] Before the abundance of present-day plastic-based debris many of these organisms were associated with natural flotsam items, like floating dead trees or sargassum.[30]

Research and cleanup

Plastics harvesting nets mounted on a vessel

In April 2008, Richard Sundance Owen, a building contractor and scuba dive instructor, formed the Environmental Cleanup Coalition to address the issue of North Pacific pollution. ECC collaborates with other groups to identify methods to safely remove plastic and persistent organic pollutants from the oceans.[31][32]

The JUNK raft project was a trans-Pacific sailing voyage from June to August 2008 made to highlight the plastic in the patch, organized by the Algalita Marine Research Foundation.[33][34][35]

Project Kaisei is a project to study and clean up the garbage patch launched in March 2009. In August 2009 two project vessels, the New Horizon and the Kaisei, embarked on a voyage to research the patch and determine the feasibility of commercial scale collection and recycling.[36]

The SEAPLEX expedition, a group of researchers from Scripps Institution of Oceanography, spent 19 days on the ocean in August, 2009 researching the patch. They took samples and spread awareness; two steps essential to the cleaning-up process.[37]

The Plastiki is a boat-building project by David Mayer de Rothschild of the Rothschild banking family of England. It hopes to highlight cleanup issues and sustainable plastic technologies.[38] The turbine-powered catamaran was constructed from 12,000 plastic bottles full of carbon dioxide and has a garden area for food growth.[39] The Plastiki set sail on 20 March 2010 upon a three-month voyage of 11,000 nautical miles from San Francisco to Sydney via the Great Pacific Garbage Patch.[39] Rothschild has used Twitter to update followers on how the voyage is progressing.[39]

References

  1. ^ See the relevant sections below for specific references concerning the discovery and history of the patch. A general overview is provided in Dautel, Susan L. "Transoceanic Trash: International and United States Strategies for the Great Pacific Garbage Patch," 3 Golden Gate U. Envtl. L.J. 181 (2009)
  2. ^ For a discussion of the problems in determining the exact size based on current sampling techniques, see Peter Ryan, Charles Moore et al., Monitoring the abundance of plastic debris in the marine environment. Phil. Trans. R. Soc. B 27 July 2009 vol. 364 no. 1526 1999-2012, doi: 10.1098/rstb.2008.0207
  3. ^ Young LC, Vanderlip C, Duffy DC, Afanasyev V, Shaffer SA (2009) Bringing Home the Trash: Do Colony-Based Differences in Foraging Distribution Lead to Increased Plastic Ingestion in Laysan Albatrosses? PLoS ONE 4(10): e7623. doi:10.1371/journal.pone.0007623
  4. ^ For this and what follows, see Moore (2004) and Moore (2009), which includes photographs taken from the patch,
  5. ^ Day, Robert H.; Shaw, David G.; Ignell, Steven E. (4), Quantitative distribution and characteristics of neustonic plastic in the North Pacific Ocean. Final Report to US Department of Commerce, National Marine Fisheries Service, Auke Bay Laboratory. Auke Bay, AK (PDF) (published 1988), pp. 247–266 {{citation}}: Check date values in: |date= and |year= / |date= mismatch (help)
  6. ^ "After entering the ocean, however, neuston plastic is redistributed by currents and winds. For example, plastic entering the ocean in Japan is moved eastward by the Subarctic Current (in Subarctic Water) and the Kuroshio (in Transitional Water, Kawai 1972; Favorite et al. 1976; Nagata et al. 1986). In this way, the plastic is transported from high-density areas to low-density areas. In addition to this eastward movement, Ekman stress from winds tends to move surface waters from the subarctic and the subtropics toward the Transitional Water mass as a whole (see Roden 1970: fig. 5). Because of the convergent nature of this Ekman flow, densities tend to be high in Transitional Water. In addition, the generally convergent nature of water in the North Pacific Central Gyre (Masuzawa 1972) should result in high densities there also." Day, etc... 1988, p. 261 (Emphasis added)
  7. ^ a b Moore, Charles (November 2003), Across the Pacific Ocean, plastics, plastics, everywhere, Natural History Magazine
  8. ^ Berton, Justin (October 19, 2007), "Continent-size toxic stew of plastic trash fouling swath of Pacific Ocean", San Francisco Chronicle, San Francisco: Hearst (published Friday, October 19), pp. W–8, retrieved 2007-10-22 {{citation}}: Check date values in: |publication-date= (help)
  9. ^ See introduction, above
  10. ^ Lovett, Richard A. (2 March 2010). "Huge Garbage Patch Found in Atlantic Too". National Geographic News. National Geographic Society.
  11. ^ Victoria Gill (24 February 2010). "Plastic rubbish blights Atlantic Ocean". BBC. Retrieved 16 March 2010.
  12. ^ For this and what follows, see David M. Karl, "A Sea of Change: Biogeochemical Variability in the North Pacific Subtropical Gyre," Ecosystems, Vol. 2, No. 3 (May - Jun., 1999), pp. 181-214 and, for gyres generally, Sverdrup HU, Johnson MW, Fleming RH. 1946. The oceans, their physics, chemistry and general biology. New York: Prentice-Hall.
  13. ^ http://www.independent.co.uk/environment/the-worlds-rubbish-dump-a-garbage-tip-that-stretches-from-hawaii-to-japan-778016.html
  14. ^ Ryan, Moore et al (2009)
  15. ^ See Moore 2004
  16. ^ Clemmitt, Marcia. "New Rules Sought for 'Floating Cities.'" Saving the Oceans 15.39 (4 Nov. 2005): n. pag. CQ Researcher Online. Web. 5 Oct. 2009. <http://library.cqpress.com/cqresearcher/document.php?id=cqresrre2005110420&type=hitlist>.
  17. ^ a b Ferris, David (May/June 2009), "Message in a bootttttllleeee", Sierra, San Francisco: Sierra Club, retrieved August 13, 2009 {{citation}}: Check date values in: |date= (help)
  18. ^ Faris, J. and Hart, K. (1994), Seas of Debris: A Summary of the Third International Conference on Marine Debris, N.C. Sea Grant College Program and NOAA{{citation}}: CS1 maint: multiple names: authors list (link)
  19. ^ Garbage Mass Is Growing in the Pacific, National Public Radio, 2008-03-28
  20. ^ "International Pellet Watch". Laboratory of Organic Geochemistry, Dr. Hideshige Takada. Retrieved 2009-05-27.
  21. ^ Thompson, Richard C. (2004-05-07). "Lost at Sea: Where Is All the Plastic?,". Science. 304 (5672): 843. doi:10.1126/science.1094559. Retrieved 2008-07-19. {{cite journal}}: More than one of |periodical= and |journal= specified (help)
  22. ^ For this and what follows, see the references provided at Photodegradation. Also, D.K.A. Barnes et al., Accumulation and fragmentation of plastic debris in global environments, Phil. Trans. R. Soc. B 27 July 2009 vol. 364 no.1526, 1985-1998 doi: 10.1098/rstb.2008.0205
  23. ^ Barry, Carolyn (2009-08-20). "Plastic Breaks Down in Ocean, After All -- And Fast". National Geographic News. National Geographic Society. Retrieved 2009-08-30.
  24. ^ Moore, Charles; Moore, S. L.; Leecaster, M. K.; Weisberg, S. B. (4), "A Comparison of Plastic and Plankton in the North Pacific Central Gyre" (PDF), Marine Pollution Bulletin, 42 (12) (published 2001-12-01): 1297–1300, doi:10.1016/S0025-326X(01)00114-X {{citation}}: Check date values in: |date= and |year= / |date= mismatch (help); More than one of |periodical= and |journal= specified (help)
  25. ^ a b Moore, Charles (2002-10-02), Great Pacific Garbage Patch, Santa Barbara News-Press
  26. ^ Rios, L.M. (2007), "Persistent organic pollutants carried by Synthetic polymers in the ocean environment", Marine Pollution Bulletin, 54: 1230–1237, doi:10.1016/j.marpolbul.2007.03.022 {{citation}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  27. ^ Tanabe, S. (2004), "PCDDs, PCDFs, and coplanar PCBs in albatross from the North Pacific and Southern Oceans: Levels, patterns, and toxicological implications", Environmental Science & Technology, 38: 403–413, doi:10.1021/es034966x {{citation}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  28. ^ Rogers, Paul. "'Pacific Garbage Patch' expedition finds plastic, plastic everywhere." The Contra Costa Times [Walnut Creek, CA] 1 Sept. 2009: n. pag. Web. 4 Oct. 2009. <http://www.contracostatimes.com/search/ ci_13258216?nclick_check=1>.
  29. ^ Flotsam Ichthyofauna in the Tropical Waters of the West Pacific Ocean
  30. ^ Fedoryako, B.I. 1980 The Ichthyofauna of the surface waters of Sargasso sea south-west of Bermuda. J.Ichthyol. 20(4):1-9.
  31. ^ Bradshaw, Kate (January 29, 2009), "The Great Garbage Swirl", Maui Time Weekly, Maui: Linear Publishing, retrieved April 26, 2009
  32. ^ The Environmental Cleanup Coalition's "Gyre Cleanup" plan
  33. ^ "A raft made of junk crosses Pacific in 3 months". USA Today. 2008-08-28. Archived from the original on 2009-09-30. Retrieved 2009-09-30.
  34. ^ "Raft made of junk bottles crosses Pacific". msnbc. 2008-08-28. Archived from the original on 2009-09-30. Retrieved 2009-09-30.
  35. ^ "Mid-ocean dinner date saves rower". BBC News. 2008-08-20. Archived from the original on 2009-09-30. Retrieved 2009-09-30.
  36. ^ Walsh, Bryan (1 August 2009). "Expedition Sets Sail to the Great Plastic Vortex". Time. Retrieved 2 August 2009.
  37. ^ Staff Writers. "Scientists Find 'Great Pacific Ocean Garbage Patch.'" Space Daily 2 Sept. 2009: n. pag. Gale. Web. 12 Oct. 2009. <http://find.galegroup.com>.
  38. ^ Maria L. La Ganga "Trash floats eco-warrior's boat" Los Angeles Times 21 Feb 2010 http://www.latimes.com/news/local/la-me-plastiki21-2010feb21,0,728915.story.
  39. ^ a b c "Boat made of plastic bottles sets sail across Pacific". BBC. 21 March 2010. Retrieved 28 March 2010.

Further reading

  • Oliver J. Dameron (2007). "Marine debris accumulation in the Northwestern Hawaiian Islands: An examination of rates and processes". Marine Pollution Bulletin. 54 (4): 423–433. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  • Rei Yamashita (2007). "Floating plastic in the Kuroshio Current area, western North Pacific Ocean". Marine Pollution Bulletin. 54 (4): 485–488. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  • Masahisa Kubota (2000). "Movement and accumulation of floating marine debris simulated by surface currents derived from satellite data" (pdf). School of Marine Science and Technology, Tokai University. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  • Gregory, M.R. (1997). "Pelagic plastics and other seaborne persistent synthetic debris: a review of Southern Hemisphere perspectives". In Coe, J.M., Rogers, D.B. (ed.). Marine Debris: Sources, Impacts, Solutions. New York: Springer-Verlag. pp. 49–66. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)CS1 maint: multiple names: editors list (link)
  • A comparison of plastic and plankton in the North Pacific Central Gyre — Charles J Moore, Shelly L Moore, Molly K Leecaster and Stephen B Weisberg
  • Density of plastic particles found in zooplankton trawls from coastal waters of California to the North Pacific Central Gyre — Charles J Moore, Gwen L Lattin and Ann F Zellers
  • The quantitative distribution and characteristics of neuston plastic in the North Pacific Ocean, 1984-1988 — R H Day, D G Shaw and S E Ignell (1988)
  • Thomas Morton, ‘Oh, This is Great, Humans Have Finally Ruined the Ocean’, Vice Magazine, Vol. 6, No. 2 (2007), pp. 78–81.
  • Hoshaw, Lindsey (2009-11-09). "Afloat in the Ocean, Expanding Islands of Trash". New York Times. Retrieved 2009-11-10.

External links

38°N 145°W / 38°N 145°W / 38; -145

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