Great Pacific garbage patch

The Great Pacific Garbage Patch is an area of debris in the North Pacific Gyre, and is also known as the Plastic soup, the Eastern Garbage Patch, and the Pacific Trash Vortex.

Phenomenon

The center of the North Pacific Gyre is relatively stationary region of the Pacific Ocean (the area it occupies is often referred to as the horse latitudes) and the circular rotation around it draws waste material in. This has led to the accumulation of flotsam and other debris in huge floating 'clouds' of waste. While historically this debris has biodegraded, the gyre is now accumulating vast quantities of plastic and marine debris. Rather than biodegrading, plastic photodegrades, disintegrating in the ocean into smaller and smaller pieces. These pieces, still polymers, eventually become individual molecules, which are still not easily digested. Some plastics photodegrade into other pollutants.

The gyre is discussed in Alan Weisman's The World Without Us as an example of the near-indestructibility of discarded plastic.

Impact on wildlife

The floating particles also resemble zooplankton, which can lead to them being consumed by jellyfish, thus entering the ocean food chain. In samples taken from the gyre in 2001, the mass of plastic exceeded that of zooplankton (the dominant animal life in the area) by a factor of six. Many of these long-lasting pieces end up in the stomachs of marine birds and animals.

Physical characteristics

For several years ocean researcher Charles Moore has been investigating a concentration of floating plastic debris in the North Pacific Gyre. He has reported concentrations of plastics on the order of 3,340,000 pieces/km² with a mean mass of 5.1kg/km² collected using a manta trawl with a rectangular opening of 0.9x0.15m² at the surface. Trawls at depths of 10m found less than half, consisting primarily of monofilament line fouled with diatoms and other plankton.

The size estimate of the patch varies depending on the source, from the size of Texas to twice as large as the continental United States. Researcher Dr Marcus Eriksen believes the Great Pacific Garbage Patch is in fact two massive areas of swirling rubbish that are linked. Eriksen says the gyre stretches from about 500 nautical miles off the coast of California, across the Northern Pacific to near the coast of Japan.

Sources

Moore estimates that 80% of the garbage comes from land-based sources, and the remaining 20% is from ships at sea. He says that currents carry debris from the east coast of Asia to the center of the gyre in a year or less, and debris from the west coast of North America in about five years.

Lost cargo

Occasionally, shifts in the ocean currents release flotsam lost from cargo ships into the currents around the North Pacific Gyre, leading to predictable patterns of garbage washing up on the shores around the outskirts of the gyre. The most famous was the loss of approximately 80,000 Nike sneakers and boots from the ship Hansa Carrier in 1990: the currents of the gyre distributed the shoes around the shores of British Columbia, Washington, Oregon, and Hawaii over the following three years. Similar cargo spills have involved 29,000-30,000 plastic yellow ducks, blue turtles and green frogs bathtub toys in 1992 and hockey equipment in 1994. These events have become a major source of data on global-scale ocean currents. Various institutions have asked the public to report the landfall locations of the objects (trainers, rubber ducks, etc.) that wash up as a method of tracking surface waters' response to the deeper ocean currents.

See also

• Sargasso Sea
• Spectacle Island (Massachusetts)
• Gyre

Further reading

• Oliver J. Dameron, Michael Parke, Mark A. Albins and Russell Brainard (April 2007). "Marine debris accumulation in the Northwestern Hawaiian Islands: An examination of rates and processes", Marine Pollution Bulletin 54 (4), 423-433.
• Floating plastic in the Kuroshio Current area, western North Pacific Ocean — Rei Yamashita and Atsushi Tanimura [Marine Pollution Bulletin; volume 54, issue 4, pages 485-488 (2007)]
• Movement and accumulation of floating marine debris simulated by surface currents derived from satellite data — Masahisa Kubota, Katsumi Takayama and Noriyuki Horii [School of Marine Science and Technology, Tokai University (2000)] http://www.aviso.oceanobs.com/documents/swt/posters2000/kubota.pdf
• Pelagic plastics and other seaborne persistent synthetic debris — M R Gregory and P G Ryan [Marine Debris: Sources, Impacts, Solutions; pages 49-66 — J M Coe and D B Rogers (1997)]
• 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 (1990)

External links

• Greenpeace facts about the North Pacific Gyre
• NPR: Navigating the Pacific's 'Garbage Patch'
• The Independent: The world's rubbish dump: a garbage tip that stretches from Hawaii
• The BBC: New 'battle of Midway' over plastic
• Algalita Marine Research Foundation
• "Oh, This Is Great", Thomas Morton, Vice
• Diary from the middle of nowhere BBC's environment correspondent David Shukman on the threat of plastic rubbish drifting in the North Pacific Gyre to Midway Atoll.
• Trashed: Across the Pacific Ocean, Plastics, Plastics, Everywhere; CHARLES MOORE / Natural History v.112, n.9, Nov03, accessed 2008-03-26
• Images and videos accessed 2008-03-26
• The plastic killing fields accessed 2008-03-26
• The Beagle Project blog