Global
warming is not the only threat that marine organisms face. In the
North-East Pacific a vortex of plastic rubbish is taking over the
ocean, swamping marine ecosystems and ultimately posing a danger
to human life. Known formally as the Great Pacific Garbage Patch
or the Eastern Garbage Patch, the phenomena arises because circulating
currents of the sub-tropical gyre naturally tend to agglomerate
floating materials in this region. Historically, floating debris
was broken down by microorganisms, but now a new class of materials
has upset this balance – in a word, plastic. Unlike naturally
occurring compounds, plastic does not photo-degrade, it simply
breaks up into ever-smaller pieces and lingers in the environment
as an invisible toxic dust.
See here for animation of the Great Pacific Garbage Patch
For the past half century plastic has been accumulating in the
central Pacific gyre. Research by Charles Moore of the Algalita
Foundation has documented that there is now 6 pounds of plastic
for every pound of phytoplankton across an area that is already
twice the size of Texas and growing every day. Around the world
100 million tones of plastic are produced each year and according
to Greenpeace 10% of it ends up in the sea. A study by the United
Nations Environmental Program estimates that in this region there
are 46,000 floating pieces of plastic for every square mile of
ocean and the trash now circulates to a depth of 30 meters. In
the Fall of 2006 the Greenpeace vessel Esperanza made a voyage
to measure the amount of debris, which exceeded even the grimmest
expectations.
When the central cell of the gyre drifts over the Hawaiian Islands,
Waimanalo Beach on Oahu is coated with blue-green plastic sand
while Midway Atoll – a major rookery for albatross – is
now a permanent trash heap. Greenpeace estimates that a million
sea birds a year die from plastic ingestion, many of them chicks
that have starved to death with bellies full of plastic cigarette
lighters, toy soldiers and bottle caps. 100,000 marine mammals
also die. Sea turtles migrating past the Garbage Patch do not know
the difference between a floating jellyfish and a floating plastic
bag and routinely chow down on the later, as do laysan and black
footed albatross. Moore has photographed transparent filter feeding
creatures, their innards laced with brightly colored plastic fragments.
And there is a darker side. Tiny fragments of plastic act as sponges
for persistent organic pollutants such as DDT and PCB’s,
oily toxins that don’t dissolve in water. Plastic pellets
in the region have been found to accumulate up to one million times
the level of these poisons – and they are entering the food
chain from the filter feeders up. One day it is we who will be
ingesting these toxins.
One of the most insidious forms of plastic pollution is nurdles,
small pellets that serve as the feedstock for all those nifty disposable
items that fill the supermarket shelves. Nurdles are manufactured
in central plastic plants then shipped around the world to factories
where they are colored and melted and poured into molds. 250 billion
pounds of nurdles are shipped each year and vast numbers of them
are spilled during transfer in and out of railroad cars. [Algalita
Foundation] Much of this spillage ends up in gutters and drains
and eventually makes its way to the ocean. One tenth of beach trash
worldwide is nurdles and they have been found as far afield as
Antarctica. When the Esperanza visited the Rubbish Vortex, every
single trawl netted nurdles. To albatross, nurdles look a lot like
clumps of roe and they are often mistaken for food and fed to infant
birds.
Scientists who study the problem say there is no solution except
to cut down on our use of plastic. Now. Of the 15 billion pounds
of plastic the US produces each year just 1 billion is recycled.
[Greenpeace] Though many plastics can be recycled in principle,
in practice sorting it into separate categories is too labor intensive
to be viable. Moreover, many complex products like cell phones
and computers have so many different plastic components that sorting
out the various types would be prohibitively expensive. Since the
1950’s plastic usage has increased tenfold every decade so
that in 2001 the average American used 223 pounds of plastic. By
the end of the decade it is estimated that our average yearly use
will be 326 pounds. [Los Angeles Times] Every hour Americans use
and discard 2.5 million plastic bottles, totaling 22 billion a year. |