Sewage And Fertilizer Creating Ocean 'Dead Zones'

The United Nations Environment Programme report calls on nations to decrease the amount of untreated sewage they dispel into the oceans. Agricultural fertilizer is also a major cause of the oxygen depletion. The Mississippi River delta outflow is a major U.S. source.

"The latest figures reveal some 200 dead zones worldwide, up from 149 since 2004. The affected waters are robbed of fish, oysters, sea grasses, and other marine life, damaging food supplies for millions of people worldwide, the report warns."

" 'There's no mistaking the consistent upward trend over the last 50 years,' said marine biologist Robert Diaz. It is difficult to estimate the total area affected worldwide, but he believes the total is 'on the order of' 300,000 square kilometers. About 80% of the zones occur every summer and autumn, he says. Some, such as the Baltic Sea's 80,000-square-kilometer zone, even persist year-round."