Archive for Ocean Sciences Meeting

Welcome to Plastic Island

Posted in Environment, Modern World, Toxic Waste with tags , , , , , , , , on 26/02/2010 by floroy1942

Have you ever wondered what happened to the plastic bottle that drifted away after you dropped it in the sea during your last visit to the beach? Well, I can’t tell you exactly where it is now, but I can make a fairly good guess as to where it will end up. If you were on the North American continent east coast or anywhere on the west coast of Europe or North African it will eventually end up some 1,000 miles SSW of the Azores.

If you were on the east coast of South America or the west coast of Central/Southern Africa it will end up some 1,100 miles SW of the island of St. Helena. Now how could he know that I hear you gasp???

Yesterday the report of a 22 year study was released by a group called the Sea Education Association (SEA) at the Ocean Sciences Meeting in Portland USA. In 1997 oceanographers discovered a huge island sized patch of floating plastic debris half way between Hawaii and the American west coast. They gave their discovery the name ‘gyre’ due to its location and how it is formed, and have now found a similar ‘gyre’ in the Atlantic.

After a study of ocean currents, scientists believe there is now a minimum of five floating conglomerations of plastic in all the world’s oceans. Apart from the one in the Pacific and the recently discovered one in the North Atlantic, there is thought to be one in the South Atlantic and one in the Indian Ocean. It seems a fair bet there will be more.

We drop a piece of plastic into the sea or local river and forget about it, but that plastic will travel thousands of miles before it reaches its final destination. It travels down rivers to the sea, and is then caught by the currents that carry it out to the deep ocean where eventually it is caught in a place where currents are weaker but surrounded by strong ones. It then moves into a circular motion from where it cannot escape.

During the study period, scientists retrieved 64,000 pieces of plastic rubbish during 6,100 sweeps of the North Atlantic. They consisted of everything from bottle caps and toothbrushes to crates plus a conglomeration of unidentifiable bits.

The maximum density of rubbish they found was 200,000 pieces per square kilometre. Because a large amount drifts just below the surface of the sea it was impossible to get an accurate measurement of the size of these plastic islands.

Trapped In Our Plastic Waste

Trapped In Our Plastic Waste

We have known for decades that our carelessness with plastic waste has had a major environmental impact, but in regard to the sea, the extent has only recently become known. Evidence has been found to confirm that many marine birds have ingested pieces of plastic thinking it was food, or swallowed it accidentally when the plastic became entangled in seaweed. They subsequently died. Large samples of fish sent for stomach analysis have confirmed that more than a third had ingested plastic. The reason is, after prolonged exposure the plastic is reduced in size by a process called photo-degradation, until it becomes about 1 centimetre across.

Relevant YouTube video:

There is little doubt that we are contaminating the seas daily with tens of thousands of tons of plastic garbage that has to go somewhere. The magnitude of this contamination has until now not been fully understood. The one remaining question is; What do we do about it? It would be prudent to clear it up, especially as nature has provided part of the answer by bringing it all together, but I fear international agreement for such a project will be a long time coming.

Next time, hang on to the bottle!

Roy.

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