Dead in the Water

The United Nations Environment Programme reported yesterday that pollution has increased the number of oxygen-starved ‘dead zones’ in the world’s oceans and seas.

There are now about 200 of these sites—more than a third as many as there were two years ago. Nutrients such as phosphorus and nitrogen from sewage, fertilizer, animal waste, and fossil-fuel burning all trigger algal blooms. After one of these explosions, the phytoplankton die and are eaten by bacteria that use up the oxygen in the water.

Not only do dead zones affect fish stocks and oysters, they’re also a threat to people who depend upon fisheries for food and livelihoods, according to the UN.

The best known dead zone is in the Gulf of Mexico, which the Mississippi River dumps fertilizer into. Traditionally these areas have appeared in the Scandinavian fjords and the Baltic, Black and northern Adriatic seas, but now they are appearing off South America, China, Japan, south east Australia and New Zealand.

The lesson: Pollution isn’t just bad for human health—it’s no day at the beach for our marine neighbors either.


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Issue 25

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