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:
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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.
References:
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