Andreas Späth

All the plastic in the sea

2014-07-21 14:13

Andreas Wilson-Späth

The fact that much of the plastic waste humanity dumps into the world’s oceans tends to accumulate in five large floating islands of garbage (two in the Atlantic and Pacific each, and one in the Indian Ocean) is common knowledge these days.

These huge vortices act as conveyor belts that accumulate the floating bits of plastic released from the continents, but exactly what happens to the plastic in them over long time periods is less well understood.

Now a new study evaluating data from an around-the-world cruise, several regional surveys and additional recent investigations has shed some light on the issue.

The researchers confirmed that the distribution pattern of floating plastic debris on the open ocean agrees with expectations, being concentrated mostly in the five known garbage patches – there is one to the east and one to the west of our own South African shoreline.

According to lead author Andrés Cózar of the University of Cádiz in Spain, “some illustrations of the plastic garbage patches in the media have not been accurate. They are enormous areas (millions of square kilometers) with dispersed but ubiquitous small plastic fragments, mainly in the order of millimeters and centimeters in size. Surface plastic concentrations in these regions are in the order of kilograms (or millions of fragments) per square kilometer”.

Cózar and his collaborators were surprised by the quantity of plastic they found. They estimate that there are currently between 7 000 and 35 000 tons of plastic floating in the worlds open oceans. But that’s much less – in the order of 100 times less – than what they expected.

Since the 1970s somewhere in the region of 100 000 tons of plastic have been released into open ocean surface waters, making for tens of thousands of tones of unaccounted for plastic. Where has it all gone?

“An unknown mechanism is removing plastic from the surface water at a fast rate,” says Cózar, ”and a large amount of plastic could be being transferred to the food chain and the ocean interior”.

We know that bits of plastic floating in the sea get broken down into ever smaller fragments as a result of exposure to sunlight and waves, but they don’t just disappear. In fact, they can last for hundreds of thousands of years.

The authors of the study believe that one possibility is that much of the plastic ends up fragmented into tiny micrometer scale particles which are not collected by conventional sampling nets and therefore remain practically invisible. Other explanations include a slow sinking of tiny plastic particles into the deeper reaches of the ocean and widespread ingestion by marine organisms, especially zooplankton and small species of fish.

The bottom line is that we really don’t know exactly what happens to a very large portion of the plastic rubbish we’re dumping into the sea (which, by the way, amounts to only about 0.1% of the annual global plastic production). There is growing evidence, however, that considerable quantities of it make their way into the marine food chain and that its ultimate destination may very well be your dinner plate.

“Marine plastic pollution has reached a planetary scale within only two to three human generations of using plastic materials,” explains Cózar. “We still don’t really know the consequences that this pollution is having on our oceans, but the effects will occur on a global scale. There are enough signs to suggest that plankton eaters, such as small fishes, are important conduits for plastic pollution and associated contaminants. If this assumption is confirmed, the impacts of sustained plastic pollution could extend to ocean predators on a large scale”.

The solution is really quite simple: let’s cut down on the vast quantities of plastic we produce, buy, use and throw away every day.

Cózar believes “that we need to tackle the problem at source. The amount of persistent plastic materials discarded globally is huge, and the global production of plastic will likely continue to increase in the coming decades. Plastic materials are key, and almost necessary, for human development in medicine, science, conservation and just about anything else, but we need to change the ways in which they are designed and used in order to improve the efficiency of usage and the recovery of plastic resources”.

- Andreas is a freelance writer with a PhD in geochemistry. Follow him on Twitter: @Andreas_Spath
 
Send your comments to Andreas

Disclaimer:

News24 encourages freedom of speech and the expression of diverse views. The views of columnists published on News24 are therefore their own and do not necessarily represent the views of News24.

NEXT ON NEWS24X

SHARE:

24.com publishes all comments posted on articles provided that they adhere to our Comments Policy. Should you wish to report a comment for editorial review, please do so by clicking the 'Report Comment' button to the right of each comment.

Comment on this story
2 comments
Comments have been closed for this article.

Inside News24

 
/News

Book flights

Compare, Book, Fly

Traffic Alerts
There are new stories on the homepage. Click here to see them.
 
English
Afrikaans
isiZulu

Hello 

Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.


Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire 24.com network.

Settings

Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.




Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.