By Bart King
This week marks the 20th anniversary of the Exxon Valdez oil spill, which released between 11 and 30 million gallons of oil into Alaska's Prince William Sound, causing an estimated $15 billion dollars worth of damages and lingering ecological effects along 1,300 miles of coastline.
And though oil spills continue to occur with increasing frequency--the most recent happened off the coast of Australia just two weeks ago--oil is not the biggest polluting threat to the world's oceans, at least not in its liquid form. Plastic is.
I was shocked to learn there is an area in the Pacific Ocean called the Great Pacific Garbage Patch that contains an estimated 4 million tons of floating plastic waste. A circulation of ocean currents causes trash discarded along the Pacific Rim to gather in this area, known as the North Pacific Gyre.
The most densely polluted area is roughly twice the size of Texas and is alternately called the Eighth Continent, the Plastic Vortex or Garbage Island.
Although floating plastic bags, bottles and foam can be seen in every direction, it's the plastic that has broken down into much smaller pieces that is the greatest cause for concern. Plastic does not biodegrade into raw minerals that can be reused by microorganisms. Rather, it photodegrades, as sunlight causes it to become brittle and break into ever smaller pieces.
Eventually these tiny pieces resemble plankton, the primary organism on the marine food chain. Researchers say random water samplings taken from the Garbage Patch contain hundreds or even thousands of plastic pieces for each actual plankton. These pieces, which don't exactly float or sink, are suspended in the top 30 meters of water, according to reports. One researcher said the underwater scene is like being inside an enormous snow globe.
Strangely enough, this soupy mess of plastic was only discovered ten years ago and studies are just beginning to evaluate its impact on the ecosystem. Early estimates suggest that on average, for every single plankton in the earth's oceans, there are six similarly sized bits of plastic. Each speck of plastic serves as a collection point for what are called persistent organic pollutants--chemical toxins like DDT and other pesticides that are already prevalent in the ocean and cling to the plastic. As a result, it's not just the plastic itself that enters the food supply.
