U.N.: Number of Ocean ‘Dead Zones’ RiseOctober 19, 2006
U.N.: Number of Ocean ‘Dead Zones’ Rise
By THE ASSOCIATED PRESS
Filed at 1:50 p.m. ET
WASHINGTON (AP) — The number of oxygen-starved ”dead zones” in the
world’s seas and oceans has risen more than a third in the past two
years because of fertilizer, sewage, animal waste and fossil-fuel
burning, United Nations experts said Thursday
Their number has jumped to about 200, according to new estimates
released by U.N. marine experts meeting in Beijing. In 2004, U.N.
experts put the estimate at 149 globally.
The damage is caused by explosive blooms of tiny plants known as
phytoplankton, which die and sink to the bottom, and then are eaten by
bacteria which use up the oxygen in the water. Those blooms are
triggered by too many nutrients — particularly phosphorous and
The U.N. report estimates there will be a 14 percent rise in the amount
of nitrogen that rivers are pumping into seas and oceans globally over a
period from when the levels were measured in the mid-1990s to 2030.
Oxygen starvation robs the seas and oceans of many fish, oysters, sea
grass beds and other marine life — and the number of such dead zones
has grown every decade since the 1970s.
Not all of them persist year-round, as they do in the Gulf of Mexico,
where the Mississippi River pours its fertilizers and other nutrients.
Some dead zones return each summer, depending on winds that generate
upwelling, in which nutrient-rich water is brought to the surface from
But all the dead zones pose a danger to global fish stocks, which many
marine scientists say are increasingly hammered by overfishing and
Dead zones first were reported in the United States’ Chesapeake Bay; the
Baltic Sea; the Kattegat bay in the North Sea; the Black Sea; the
northern Adriatic Sea; and some Scandinavian fjords.
Others have appeared off South America, China, Japan, southeast
Australia and New Zealand, according to U.N. research led by Robert
Diaz, a marine scientist at Virginia’s College of William & Mary.
Diaz and his team reported finding new dead zones in Finland’s
Archipelago Sea; Ghana’s Fosu Lagoon; China’s Pearl River estuary and
Changjiang River; Britain’s Mersey River estuary; Greece’s Elefsis Bay
and Aegean Sea; Peru’s Paracas Bay; Portugal’s Mondego River; Uruguay’s
Montevideo Bay; and the Western Indian Shelf.
United Nations report: