Sunday, December 21, 2014

The Great Pacific Garbage Chowder

The Great Pacific Garbage Patch: it's flashy, disturbing, simple, a great band name, and... is completely misleading. That name was given to an area in the Pacific ocean by Curtis Ebbesmeyer when a colleague reported on the amount of floating plastic in the area. Because the name is so catchy it stuck, and has been used extensively in popular media reports ever since. So what's it look like? Well prepare yourself, below you're going to see a picture from the very heart of this trash zone that's been described as having a surface area twice the size of Texas.

Where's all the garbage?
Courtesy:  ---=XEON=--- via Panoramio

The problem with the term patch is that it suggests a covering, like in a patch of grass; or a lot of big pieces, like in a cabbage patch. Neither of these is what you see in these areas. Really what's happening is that giant ocean currents, called gyres, are concentrating tiny bits of plastic (called microplastic) in their middles. The gyres are more like plastic chowder than a plastic patch. And just like in a chowder the chunks aren't evenly distributed. Different types of plastic have different densities, so they float at different heights in the water column or even sink to the bottom.

This is the North Pacific Gyre. There are two major gyres in the Atlantic and Pacfic,
 and one in the Indian Ocean
Courtesy: NOAA Ocean Service's Making Waves podcast

So why isn't the plastic more evenly distributed, or at the very least why isn't it close to land? Well it has to do with the fact that the gyres are circular currents. When particles sit in water they are partly held up by how fast the water is moving. In swirling water, like the gyres or a cup of tea being stirred, the water at the center is moving slower than the water at the edge. Particles catch on the slow water and are pulled into the center where they stay more or less still.

 Red sprinkles in water before, during, and after stirring: Some sprinkles float, others sink; all concentrate into the center; just like pieces of plastic caught in the ocean gyres.

There are a number of issues associated with plastic in the ocean, and all originate with the fact that plastic doesn't biodegrade. Plastics are designed to last forever; they're stable, cheap, and sturdy. When we throw out plastic it never turns back into the minerals that it came from. Plastics just continually degrade into smaller and smaller pieces, but they stay plastic for functionally forever.
The first problem is that plastic takes up space. Several studies over many years have led to calculations of about 35,000 tons of microplastic and 250,000 tons of larger plastics in the oceans. All of those bits can easily lead to entangled marine animals.

The other big issue is that act of breaking down. As plastics break into smaller and smaller shards they're inadvertently gobbled up by smaller and smaller organisms, entering the food chain at more levels. While they're breaking apart and mixing around in the ocean, the chemically raggedy edges of the plastic grab onto many of the toxins commonly found in sea water. This takes those chemicals from their spread out, and therefore less dangerous, state to concentrated on one of these bits. Some of these toxins are hormone disruptors and there's a growing body of evidence that they can and will affect fish by changing their reproductive organs to those of the opposite sex.

Lastly, when plastic breaks down it becomes much harder to clean up. Imagine trying to separate all the parts out of real chowder, including the spices. Some of it can be picked out pretty easily, but others not so much. The microplastics are so small that we can't go out and grab it all because we'd have to screen the water with nets with really tiny holes. Nets with tiny holes are also how you catch plankton, so to catch the estimated 5 trillion bits of plastic out there we would probably decimate plankton populations.

"A few billion more of these and we can save and destroy the ocean at the same time"
Courtesy: NOAA Photo Library via Flickr

There's also the problem of some plastic sinking. For years surveys of ocean plastics weren't finding as much as researchers expected, but we knew that our waste was making into the ocean, so where was it all going? Well it turns out, straight to the bottom. A three ocean study of deep sea sediments has found significant amounts of microplastic fibers in the depths. A lot of these fibers were rayon and acrylic, materials found in synthetic clothing that probably got into the water from particles coming off as the clothes were washed.

Alright if we can't clean up everything then what do we do? Well the beautiful thing about this issue is that it's entirely in our hands. There isn't a single company or government that has caused all this pollution, so there's no one to fight with to make it stop. We are so powerful in this situation it's unprecedented. The most important thing is to stop using plastic like it has a short life. That tupperware you or your parents bought in the 70's and is still in your kitchen; that's how plastic should be used. Keep that sucker around forever and hand it down to your kids too. Those Legos that have been dropped, washed, stepped on, pummeled, and still haven't broken. Hell yeah that's my kind of plastic. Where you can, eliminate single-use products, and when you're out walking pick up a piece of litter each time. If we do these things we can make a dent in the 30% of all plastic that gets thrown away within a year.

I have to give credit to Edward Humes, author of Garbology for the term "plastic chowder" it really is a perfect metaphor.


Cozar et al., "Plastic Debris in the Open Ocean", Proceedings of the National Academy of Sciences, Vol. 11 No. 28, 2013, DOI 10.1073/pnas1314705111

Ericksen et al. "Plastic Pollution in the World's Oceans: 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea", PLOS ONE, 2014, DOI 10.1371/journal.pone.0111913

Woodall et al, 2014, "The Deep Sea is a Major Sink for Microplastic Debris", Royal Society Open Science, 1:140317,

Rochman, Chelsea, "A Story About Fish, Plastic Debris, and Sex", Deep Sea News, 2014,

Humes, Edward, "Garbology", Ch. 5-6, Penguin Books, 2013

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