Friday, 27 December 2013

The Great Pacific Garbage Patch

In 1997, Charles Moore, a Californian racing boat captain, discovered the Garbage Patch, an ocean area of millions of square kilometers containing excessive floating plastic, on his way home from Hawaii (Grant 2009). The Patch is located in the northern Pacific Ocean and is caused by the North Pacific Subtropical Gyre, which is the clockwise spiral of currents created by a high-pressure air system between East Asia and North America (Silverman). The air in the gyre center is very calm and stable, and the inward motion draws in debris at the convergence zone, eventually making its way to the gyre center, where it accumulates (NatGeo). According to Marcus Erikson, director at Algatita Marine Research Foundation, it is the ‘perfect environment for trapping’ debris (Reid).

Figure 1. Location of the Garbage Patch relatively to the Subtropical Convergence Zone.
Source: NOAA 
 
The Garbage Patch is an oceanic desert that contains phytoplankton and few big fish and mammals (Silverman). The ratio of plastic to plankton is 6:1 (Grant 2009). The plastic weighs three million tons (Reid), 80% of which comes from land (Grant 2009). Contrary to popular belief, the debris mostly consists of microplastics, which cannot be seen by the naked eye (NatGeo).   

The Great Patch is divided into two masses: the Eastern and Western Patch, with Hawaii separating the two (Reid). In total, it is twice the size of France (Grant 2009) and has tripled since the 1990s (Reid). The debris is continuously mixed by wind and wave action, and disperses over a wide area and through the top of the water column. The Patch collects trash mainly from North America and Asia (NatGeo). In 2004, EPA reported that the USA released 850 billion gallons of untreated sewage per year, including cotton buds, condoms, and dental floss (Hohn 2008).

According to UNEP, there are 46,000 floating plastic pieces per square mile of the Patch. Plastic doesn’t biodegrade; it photodegrades by long exposure to sunlight, fragmenting into smaller pieces without breaking into simpler compounds. The manufactured 2mm pellets (nurdles) concentrate toxic hydrophobic chemicals such as POPS, dioxin and D.D.T, to around one million times the normal value (Reid). Plastic becomes ‘poison pills’, and once they enter filter feeders, they move up the food chain (Hohn 2008). Each year, more than one million birds and marine animals die from entanglement or ingestion of plastic (NOAA). The most famous victim is the Laysan albatross:


 Figure 2. Greenpeace ad 'how to starve to death on a full stomach' to raise awareness on wildlife destruction in the Garbage Patch. The photo on the right displays the plastic content found in this albatross.
Source: Greenpeace

No nation is taking responsibility to fund the cleanup (NatGeo). Trying to remove the garbage will cost billions, as it is widespread over a large area and to ~30m depth. The first crucial step is to decrease plastic reliance (Reid). Environmentalist David de Rothschild says that the annual budget for the United Nations Environmental Programme last year was $190 million. And the budget for the latest James Bond movie was $205 million (Grant 2009).

So, future geologists, get ready to see plastic-coated strata marking the 20th and 21st centuries. 


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