You may have heard about it…the giant patch of plastic in the Pacific Ocean.
I first got to know about this through a guest-lecture at my university in Wageningen (in the Netherlands). To be honest I don’t remember much of what he talked about, it was 6 or 7 years ago, but it did make an impression. He showed pictures of birds (dead) with their stomachs full of plastic bits, giant patches of plastic bottles floating about in the ocean, pretty shocking stuff for a biologist (or anyone else I guess).
So, what’s up with this plastic garbage patch?
The garbage patch I am talking about here, is located in the Pacific Ocean. Or actually, there are two garbage patches. One is located east of Japan (the Eastern Garbage Patch), and the other one is located just north of Hawaii (the Western Garbage Patch). Each patch is double the size of the state Texas, and is about 10 metres deep. The Pacific Ocean might be big, but this is more plastic than it can handle!
How does all this plastic end up in these specific places, you’re thinking?
A bit of basic oceanography. In all the oceans you will find currents. There are big currents that connect all the oceans together, and from these big currents spring smaller currents within each ocean. These currents are called gyres, and they are caused by differences in pressure, temperature and salinity of the water, and the wind. When the wind makes contact with the ocean surface, the water is set in motion. If the wind persists for long enough, this motion descends through the water column, causing a spiralling current (called the Ekman spiral) (Pinet, P.R., 2009). And it is these Ekman spirals and gyres that cause the plastic to collect in these garbage patches. See the yellow dots in the map? That’s plastic. Now the plastic starts moving, following the white arrows on the right and the blue ones on the left, and the Ekman currents and winds keep it all in place (click the map to go to the website for an animated version).
Plastic is an anthropogenic (man-made) kind of garbage. It is estimated that 80% of plastic in the oceans comes from sources on land, and the other 20% come from activities on sea, such as fisheries, cruises, and shipping (Lebreton et al, 2012). The debris consists of pretty much anything plastic you can think of. Bottlecaps, toothbrushes, floating fishnets, bottles, and tiny bits of plastic (Hoshaw, L. 2009). Just try to think of how much plastic you deal with every day…your food is wrapped in it (lots of it for some reason), your computer has plastic in it, your phone, cars. And plastics are not easily biodegradable, which is why all that plastic is floating there in the Pacific Ocean, and why the patches keep growing.
When we have a closer look at what plastics the patch consists of, there are the macro-plastics (the bottles, toothbrushes, bottlecaps etc) and the micro-plastics (tiny particles of plastic). What we see in all the pictures are mainly the macro-plastics. The birds with their stomachs full of plastic bits, a turtle with a plastic ring around its shell, littered beaches full of plastic.
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| Photo by Chris Jordan |
But it's the micro-plastics that are the major constituent of the garbage soup. And despite them being so small, they are dangerous! Because of their size the particles are mistaken for food by marine organisms, and they get ingested by the animals. The composition of the particles makes it easy for pollutants in the water to attach onto these mini-plastics (Cole et al, 2011). This is chemics, and I am not good at that, so I am going to take the scientists word for it here...A lot of the pollutants are toxic for animals (and humans), so by ingesting the plastic bits, fish, dolphins, and us humans, accumulate the toxins in their bodies, which is obviously not a very healthy business to be doing.
Why does this garbage patch get so little attention? First of all, until not too long ago we were simply not aware of its existence. The Pacific Ocean is immense. Until captain Charles Moore came across it with his crew in 1997. 'It seemed unbelievable, but I never found a clear spot. In the week it took to cross the subtropical high, no matter what time of day I looked, plastic debris was floating everywhere.' (Moore, 2003). Secondly, because it's so far away. If a problem is not directly on your doorstep, it is quite easy to think: this is not my concern. But it is! Since the discovery, efforts to raise awareness have increased. But still, you don't hear much about it, until you start looking for information. The problem certainly has not become any less since captain Moore discovered it...we keep producing more plastic every day, and it won't break down or disappear by itself.
So is there anything we can do? Fishing out all the macro-plastics seems like an idea...but men, that would take ages! What would you do with all the plastic? And who would pay for it? Even if all this works, there is still the issue of the micro-plastics. Much more difficult to target...then I remembered a Tedx Talks video that appeared on my facebook feed a while back. I am impressed! This guy (he is quite young) has some really interesting ideas. It's still a project of massive proportions, but he makes it sound like there might be a solution. We're not there yet. His concept is promising, but they are still studying the feasibility of it. I hope it works, and that there will be enough investors to make it happen once he gets to that point.
In the mean time: put your garbage in the bin. Just like that, we already help.
References:
Hoshaw, L. (2009, November 10). Afloat in the ocean, expanding islands of trash. New York Times
Lebreton, L.C.-M., Greer, S.D., and Borrero, J.C. (2012) Numerical modelling of floating debris in the world’s oceans. Marine Pollution Bulletin, 64, 653-661.
Moore, C. (2003) http://www.fvrd.bc.ca/InsidetheFVRD/MeetingsAgendasMinutes/AirQualityandEnvironmentManagement/Archived%20Agendas/2010%2003%2002%20Environment%20Committee/item%206.2%20-3%20Email%20re%20Recycling.pdf
Pinet, P.R. (2009) Invitation to Oceanography (5th ed.). Sudbury, MA: Jones and Bartlett Publishers.
Other websites:
http://www.greenpeace.org/international/en/campaigns/oceans/pollution/trash-vortex/
http://response.restoration.noaa.gov/about/media/where-are-pacific-garbage-patches.html
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