The Ocean as a floating rubbish dump

Ecology Today has drawn attention to the huge plastic waste dump which has grown and expanded in the Northern Pacific Ocean measuring twice the size of the continental United States. It stretches from around 500 nautical miles off the coast of California all the way to Japan to a depth of 10 metres below the surface of the sea.

Sea currents transport the waste into ocean “dead zones”, large areas of water that are slow moving circular currents which trap debris into one large constantly moving mass of plastic. This mass of plastic is slowly being broken down into a plastic dust that marine wildlife mistake for food with the result that many species in the food chain from fish through to ocean birds are being affected. The UN Environmental Program estimates that over a million seabirds, as well as more than 100 thousand marine mammals, die every year from ingesting plastic debris.

Ecology Today reports that the area is known as the Northern Pacific Gyre, one of five gyres in the world’s oceans. These gyres are areas of sea where water circulates clockwise in a very slow spiral. As winds are light the currents tend to force any floating material into the low energy centre of the gyre thus everything afloat becomes trapped in these “dead zones”.

Besides being a danger in itself, these vast areas of plastic pollution act as chemical sponge attracting other damaging pollutants, such as persistent organic pollutants (POPs), hydrocarbons and pesticides such as DDT that have leached or been released into the oceans from runoff or drainage. While this pollution contains huge amounts of plastic waste not all of it is floating on the surface as wave action and the heat of the sun degrades the plastic into smaller particles.

The need for action to reduce plastic contamination could not be greater given the scale of the existing environmental degradation.