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Ocean garbage patches are not growing, so where is all that plastic going?

The views expressed are those of the author and are not necessarily those of Scientific American.

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Atlantic, Pacific,SEAResearchers have been visiting locations in the western North Atlantic Ocean and Caribbean Sea for more than two decades to better understand the large patches of plastic that have formed there. Although the mysteries surrounding exactly how the plastic gets to these locations, where it comes from and what impact it’s having on marine life remain unanswered, a team of scientists has now published perhaps the most analytical study of the patches to date based on data collected by research vessels over a 22-year period, between 1986 and 2008.

The researchers from Sea Education Association (SEA), Woods Hole Oceanographic Institution (WHOI) and the University of Hawaii (UH) found, among other things, that the amount of plastic picked up by the researchers’ nets remained pretty stable over the years, despite society’s increased production and consumption of plastic, according to research published in Thursday’s issue of Science Express.

More than 64,000 individual plastic pieces were collected at 6,100 locations that were sampled yearly over the course of the study. To collect these data, ships towed nets along the water’s surface at each location, and researchers used tweezers to pick the small plastic bits out of the algae and other collected material. More than 60 percent of the surface plankton net tows collected buoyant plastic pieces that were typically millimeters in size. The highest concentrations of plastic were observed in a region centered at roughly the latitude of Atlanta.

By combining their measurements with a computer model of ocean circulation, the researchers report that this concentration of plastic occurred in an area where wind-driven surface currents were converging. The researchers think this helps explain why the debris accumulates in this particular region, so far away from land. The authors propose a handful of possible explanations for why the patch hasn’t grown rapidly since its discovery. The plastic there may break up into pieces too small to be collected by the nets, or it might be sinking beneath the surface. Or, it might be consumed by marine organisms. More research will be necessary to determine the likelihood of each scenario, the researchers conclude.

Several expeditions launched over the past year indicate that the Pacific Ocean is likewise afflicted by large islands of floating garbage. The plastic trash that makes up the Great Pacific Garbage Patch has become a become a popular snack bar for the local Laysan albatross (Phoebastria immutabilis) population, a team of researchers led by the University of Hawaii reported in October 2009. The researchers found that colonies of the birds living near two different garbage patches were eating lighters, fishing line and oyster spacers likely discarded at sea by those in the fishing industry as well as more commonplace trash. One Kure Atoll chick that died was found to have 306 pieces of plastic inside of it, according to the researchers.

Project Kaisei—a team of scientists, sailors, journalists and government officials funded in part by international recycling companies—likewise visited the Great Pacific Garbage Patch a year ago. The crews of the Kaisei and a second ship (the New Horizon, launched from San Diego’s Scripps Institution of Oceanography) looked at how decomposing plastic over the past few decades has mixed with phytoplankton and zooplankton and investigated whether netting techniques might be used to clean it up. These researchers noted another reason why a plastic patch may not appear to grow over time: much of the plastic is broken down in a soupy mix that tends to move around as ocean currents and storms produce swells and wind over the course of a given year.

A team of researchers from the Algalita Marine Research Foundation in Long Beach, Calif., returned from its own two-month voyage to study the garbage patch last August humbled and disheartened by what they saw. Project videographer Drew Wheeler concluded: "We must stop this from getting worse by reducing or eliminating the use of non biodegradable plastic for disposable products and product packaging. If the increasing rate of plastic in the ocean does not change, then I do not see how we can avoid catastrophic changes in the health of our marine ecosystem and, as a result, to human life itself."

Image of surface plankton net being towed through the water to collect microscopic organisms and plastic marine debris courtesy of SEA/Gloria Proskurowski

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  1. 1. frgough 11:01 am 08/20/2010

    So, the entire article talks about how the plastic is NOT getting worse, but the last paragraph, goes on an hysterical rant about how all life is doomed because even though we can’t find any more plastic, we know that it MUST be there. Because, well, capitalism sucks.

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  2. 2. rhodinsthinker 11:40 am 08/20/2010

    Apparently, some of the plastic is ging into the animals who eat it.

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  3. 3. Texxas 12:17 pm 08/20/2010

    These plastic patches seem like they’d be ideal places to harvest plastic for recycling. Skim the plastic off the surface, grind it up by the ton, transport it, and recycle it. Even if it didn’t recoup the full costs of the program, it seems like there could be some international fund to pay for restoring the oceans.

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  4. 4. katesisco 12:54 pm 08/20/2010

    Perhaps, again, as the second to last paragraph notes, the smaller particles don’t stay in place, they move with the wind across the seas. Curtis Ebbersmeyer’s book: Flotsametrics is a great read & records years of information gleaned from our floating junk plastic in the ocean gyres.

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  5. 5. katesisco 12:57 pm 08/20/2010

    perhaps, as the second to last paragraph states, the small particles move across the surface of the sea with the wind. Curtis Ebbersmeyer’s book: Flotsametrics documents years of our floating junk plastic circling the ocean’s gyres.

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  6. 6. brynn217 1:19 pm 08/20/2010

    Umm if you read, they believe the majority of the plastic is degrading into a "soupy mix" this may be a way of the plastic breaking down.. and if anyone knows what makes plastic.. it’s OIL… and do we really want THAT Much oil foating around in the underwater jet streams? It may actually be more oil then BP has already dumped in our oceans…

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  7. 7. brynn217 1:21 pm 08/20/2010

    the "Soupy mix" refered too is what the majority of the plastic seems to be disolving into.. if anyone knows what the major component of plastic it, its oil…. A hasnt BP already dumped enough oil into our Oceans…. this much plastic could actually be more Oil then BP’s.. and it includes other containament as well… so just be aware of where your trash ends up.

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  8. 8. Squish 1:33 am 08/23/2010

    frgough: "Because, well, capitalism sucks" –> Because, well, [unregulated] capitalism sucks. Important difference.

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  9. 9. Chemluo 8:28 am 08/23/2010

    Humans are always trying to find the adverse effects of what we have done, even though we’ve already know they are somewhere around us.

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  10. 10. mpease46 1:44 pm 08/23/2010

    With our luck we’ll go the way of Larry Niven’s Ringworld Engineers: their civilization collapsed when bacteria evolved that ate the plastic insulation on all their electronics.

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  11. 11. Debris Researcher 2:00 pm 08/25/2010

    The findings from the SEA/WHOI cruise analyses are very specific. The data reported states that there was no significant increase in the amount of debris between 1986 and 2008. Concurrent with this research is another paper detailing beach debris collected from 1997-2007 in the same geographic region along the East Coast recently published in Marine Pollution Bulletin by C.A. Ribic, et al. That research also produced the same findings regarding the amount of marine debris documented along East Coast beaches — no significant increase from 1997-2007. Those researchers propose that other factors such as improvements in solid waste management during this same period may have influenced the results. To propose that any trash not collected on land has to end up in the ocean is unrealistic and is not substantiated by reliable data. This assumption needs to be tested and involve solid waste management experts in providing the missing information from SEA’s statistics. More research is needed in sampling for smaller components in the ocean, but do not make assumptions that increased recycling efforts and changes in behavior by the public in how they handle their solid waste have not also occurred during this same time period.

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  12. 12. 4:43 pm 05/25/2011

    The print version of this story spends some time reporting that researchers have found holes in the plastic indicating that some marine microbes may have evolved with an ability to digest plastic and gain nourishment from it. However, I no longer have my copy of the magazine. Can’t find anything like that in the online version. So what happened to those most interesting observations?

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