POLLUTION OF THE OCEANS
The large zone of waste in the Pacific, also known as the "Pacific Trash Vortex" is comprised of 100 million tons of trash concentrated in the Northern Pacific Ocean. The zone stretches out over an enormous surface area, estimated to be more than twice the size of the United States (??).
Recent research has shown that vortexes of trash also exist in the Atlantic Ocean and the Mediterranean Sea.
Although this includes waste of all kinds, like fishing nets or plastic bottles, the largest part of these vortexes consists of microscopic plastic debris that are difficult to see with the naked eye. These small particles, which measure less than five millimeters in size, come from larger pieces of plastic debris that disintegrate over time, because of the waves and photodegradation (the degradation of certain kinds of plastics through ultraviolet light).
THE IMPACT OF PLASTIC WASTE ON THE MARINE ECOSYSTEM
The worldwide production of plastic has increased by more than 500% over the past 30 years. In North America and Europe, each individual uses about 100kg of plastic a year – a number which should be around 140kg by 2015. In contrast, each individual in Asia's developing countries uses about 20kg of plastic a year – a number which should be around 36kg in 2015. The impact this increased consumption of plastics has on the ecosystem was discovered by the oceanographer Charles Moore, during his voyage in the Pacific Ocean in 1997. He was navigating the intertropical convergence zone – an area that is usually avoided by navigators because of the lack of wind – when he found himself in what he later described as "the Pacific's large zone of trash."
Following his discovery, a number of scientists and cartographers, including Moore, started to measure the extent of the impact these plastic debris have on the oceans. The United Nations Environment Program (UNEP) established in its 2011 annual report that more than 260 species were thought to have been trapped by the debris, or have swallowed it. A recent study on plankton-eating fish in the Northern Pacific Ocean showed that each of them had swallowed an average of 2.1 plastic objects. Plastic waste causes the death of more than one and a half million ocean birds and more than one hundred thousand marine mammals every year.
The UNEP's report also mentions a study showing that as plastic waste decomposes, it releases chemicals that may be toxic to both humans and the marine ecosystem, like bisphenol A (BPA) and a polymer called PS oligomer.
The Great Pacific Garbage Patch, also described as the Pacific Trash Vortex and the “8th Continent”, is a gyre of about 100 million tons of marine litter in the central North Pacific Ocean. The patch extends over a very wide area, which some scientists estimate to be more than twice the size of the continental United States. Recent researches have also identified plastic gyres in the Atlantic Ocean and in the Mediterranean Sea.
While larger items can be found in these areas, along with other debris such as abandoned fishing nets, much of the litter is actually small bits of floating plastic debris – microplastics - that are difficult to see with the naked eye. These tiny pieces of plastic, smaller than five millimeters in length, are formed as a consequence of bigger pieces of plastic broken down over time by things like waves and sunlight.
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