The enormous soup of plastic debris in the Pacific has grown rapidly to twice the size of the U.S. An ongoing voyage into the foul soup of garbage has revealed it is composed of two huge vortices one in the eastern Pacific and one in the western Pacific. The vortices are maintained by a confluence of subsurface currents and by regions of high atmospheric pressure above the subtropical Pacific Ocean.
These plastic patches have profound implications for wildlife because birds tend to eat bits of plastic and marine mammals can be strangled by them. Moreover, the plastic can accumulate in areas where currents are forcing nutrients upward - zones of high biological activity. The consequences are deadly to a wide range of species.
Continued investigation of the plastic patch has shown it is larger and more diffuse that previously reported. What was previously called an island of plastic is now being called a soup of garbage.
The vast expanse of debris – in effect the world's largest rubbish dump – is held in place by swirling underwater currents. This drifting "soup" stretches from about 500 nautical miles off the Californian coast, across the northern Pacific, past Hawaii and almost as far as Japan.
Charles Moore, an American oceanographer who discovered the "Great Pacific Garbage Patch" or "trash vortex", believes that about 100 million tons of flotsam are circulating in the region. Marcus Eriksen, a research director of the US-based Algalita Marine Research Foundation, which Mr Moore founded, said yesterday: "The original idea that people had was that it was an island of plastic garbage that you could almost walk on. It is not quite like that. It is almost like a plastic soup. It is endless for an area that is maybe twice the size as continental United States."
I have witnessed the effects of this soup when it drifts south in winter and deposits debris on Kauai's beaches. The large pieces of broken fishing nets are potentially deadly to marine mammals. After a storm the beaches can look like garbage dumps.
Curtis Ebbesmeyer, an oceanographer and leading authority on flotsam, has tracked the build-up of plastics in the seas for more than 15 years and compares the trash vortex to a living entity: "It moves around like a big animal without a leash." When that animal comes close to land, as it does at the Hawaiian archipelago, the results are dramatic. "The garbage patch barfs, and you get a beach covered with this confetti of plastic," he added.
The "soup" is actually two linked areas, either side of the islands of Hawaii, known as the Western and Eastern Pacific Garbage Patches. About one-fifth of the junk – which includes everything from footballs and kayaks to Lego blocks and carrier bags – is thrown off ships or oil platforms. The rest comes from land.
Daily reports on the voyage into plastic pollution patch by the Oceanographic Research Vessel Alguita are posted on their blog. They set out for the pacific gyre from Hilo Hawaii on January 2 and will return to port in Los Angeles. Their fall voyage showed that the area of the debris soup had grown five times larger in just ten years since it was discovered in 1997. Yesterday's report brought more alarming news.
Charles and Marcus, shown here, stood at the bow ready to net any floating debris, an activity usually resulting in a few synthetic strays here and there – bottle caps, large shards, bits of fishing line, etc. Soon however, they were pulling up large pieces every other minute. We’d happened on a Langmuir windrow , a series of circular counter currents that meet, sweeping mixed layer sub surface materials to the top, into a sort of oceanic river, visible as a slick on the ocean surface. In a perfect world, this would consist mainly of nutrients – plankton, spawn, etc. – attracting seabirds and other marine creatures to feed. This, as you may have guessed, was a waste windrow – a visible line of floating debris.
According to Charles, this was the second most dramatic windrow he’d ever seen, and the widest yet. Many of the larger pieces showed clear signs of "fouling" – covered with growth, and often gnawed to pieces. Both plastic baskets contained fish, the monofilament drift net with a dozen new banana floats was also, along with lots of pelagic crabs. A five foot piece of 3" diameter tubing that looked like PVC tubing, but was white on the outside and black on the inside and floated (PVC sinks in seawater) once removed, housed a triggerfish that came flopping out onto Jeff.
A surprising aspect of this debris is that it had been submerged for a long time and was recently driven to the surface by converging counter currents. The investigators are challenged to try to determine how deep the debris can be submerged. They know now it is not simply a floating island of garbage.
Here’s the Captain with our day’s haul, an impressive collection. By his accounts, this debris had been at sea for some time, and based on its growth, had resided at deeper levels. The bottle that was floating on the surface not in a windrow was heavily encrusted with barnacles, but the crates and float parts in the windrow had hairy growths characteristic of deeper debris. Future studies may look at ways to determine the depth at which debris has been residing.