|
Our Oceans: More "Dead Zones" |
|
Written by wbnet
|
|
August 15, 2008 · A global study shows the number of "dead zones" — areas of ocean with too little oxygen for most marine life — has increased by one-third since 1995. In the latest issue of the journal Science, researchers say these polluted waters are the leading threat to life in coastal oceans. Source: NPR There are now more than 400 known dead zones in coastal waters worldwide. Low oxygen, known as hypoxia, is a significant measure of the downstream effect of chemical fertilizers used in agriculture. Air pollution is another factor. The nitrogen from the fertilizer or pollution feeds the growth of algae in coastal waters, particularly during summer. The algae dies and sinks to the bottom, where the organic matter decays in a process that robs the bottom waters of oxygen.
Hypoxia has been seen for decades in such places as the Chesapeake Bay, Lake Erie, the Gulf of Mexico and Long Island Sound,
New zones have been found in the Florida Keys, Washington state's Puget Sound and tidal creeks in the Carolinas.
Read an article on this subject: |
