Friday, July 16, 2004

The Dead Zone

'Dead zone' a threat to Chesapeake Bay

Like the bill city residents get for sewage disposal, the dead zone reflects the cost of pollution to the bay's natural environment.

Scientists have known for at least 20 years that the bay suffers from too much nitrogen and phosphorous. Sewage effluent, malfunctioning septic tanks and animal waste and fertilizers that wash off the land furnish the nutrients. The nutrients feed algae and phytoplankton in the bay and its rivers. Those organisms die and the bacteria present during their decomposition use vast quantities of oxygen.

Dead zones caused by nutrient over-enrichment are a problem the world over. A low-oxygen zone in the Gulf of Mexico created serious problems with fisheries there.

Click, click, click. What channel was that program on?

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