Dead Zone Count Rises to About 250 Worldwide

August 15, 2007

It's the time of year when dead zones are prominent all over the northern hemisphere. Their causes are varied: massive runoff of fertilizer from agricultural fields and other lands; extreme rainfall that flushes more pollutants than normal; extreme drought that reduces inflows, concentrating harmful substances in certain water bodies; ocean current shifts suspected to be linked to global climate change; and combinations of these.

Whatever the cause, the result is large swaths of oceans or lakes that are sharply depleted in or completely devoid of oxygen, ruining their normal ability to support much life. The death traps can last for weeks or months, and can result in major biological changes that may endure for years.

The number of documented dead zones around the world is climbing quickly, rising from about 150 sites three years ago to about 250 anticipated by the end of this year. They are occurring off extensive stretches of the US Atlantic, Gulf, and Pacific coasts, and in the Caribbean, Central and South America, Europe, the Middle East, Africa, India, China, Japan, Korea, Australia, and New Zealand. Often they occur near the mouths of major rivers. For a map and more information, contact Robert Diaz of the Virginia Institute of Marine Science, 804-684-7364.

Some starting points for background on, and people who can talk about, a few of the more prominent US dead zones include:

GULF COAST

CHESAPEAKE BAY

PACIFIC NORTHWEST

LAKE ERIE

GENERAL INFORMATION