'Dead zone' in the Gulf of Mexico is the size of Connecticut

ORLANDO Fla. Tue Aug 5, 2014 2:12pm EDT

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ORLANDO Fla. (Reuters) - Scientists say a man-made "dead zone" in the Gulf of Mexico is as big as the state of Connecticut.

The zone, which at about 5,000 square miles (13,000 sq km) is the second largest in the world but still smaller than in previous years, is so named because it contains no oxygen, or too little, at the Gulf floor to support bottom-dwelling fish and shrimp.

The primary cause of the annual phenomenon is excess nutrient runoff from farms along the Mississippi River, which empties into the Gulf, said Gene Turner, a researcher at Louisiana State University's Coastal Ecology Institute.

The nutrients feed algae growth, which consumes oxygen when it works its way to the Gulf bottom, he said.

"It's a poster child for how we are using and abusing our natural resources," Turner said.

Turner said the zone has at least twice in recent years reached the size of Massachusetts, about 8,200 square miles (21,000 sq km).

The Gulf dead zone, which fluctuates in size but measured 5,052 square miles this summer, is exceeded only by a similar zone in the Baltic Sea around Finland, Turner said.

The number of dead zones worldwide currently totals more than 550 and has been increasing for decades, according to a report by Turner and Nancy Rabalais from the Louisiana Universities Marine Consortium.

The elongated Gulf zone typically hugs the Louisiana coastline from the Mississippi River Delta to the state's border with Texas, and some years extending offshore of Texas and Mississippi, Rabalais said.

The scientists said a growth in farmed land along the Mississippi River in the 1960s began increasing pollution. In the 1970s, levels of oxygen in parts of the Gulf fell below the needs of bottom-dwelling fish. The zone has been generally growing ever since.

Floods, droughts, storms and other factors affect the volume of nutrients flowing into the Gulf and account for year-over-year fluctuations, Turner said.

"It seems to have leveled out in size, but it could get worse" depending on changes in pollution levels, Rabalais said.

The report said federal farm policy impacts the amount of pollution in the river. Turner said corn fields, which lay bare most of the year and leach nutrients, are one of the biggest contributors to the problem.

A federal task force organized with river states in 2001 to reduce nutrient runoff has had no substantial success, he said.

(Editing by Karen Brooks and Sandra Maler)

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Comments (7)
LiberalGuy43 wrote:
I would be interested to know what effect the oil spill and the surfactants pumped into the gulf by BP had to exacerbate the damage. The report seems to avoid even discussing this possible interaction. Oil has a high BOD and should not be left out of the contributing factors.

Aug 05, 2014 7:55pm EDT  --  Report as abuse
The BOD associated with oil is high in the Gulf because of the native oil metabolizing organisms. The high BOD also comes with a low duration. Oil from years ago is not a likely suspect. The Article explaned that there was an algae bloom. The Algae oxygenates the water and other organisms multiply rapidly. That area is naturally rich in nutrients from the coastal swamps. It is also relatively stagnant and has no abropt depth changes. The absence of river flowing into the gulf in that area also sets the stage for this kind of bloom. The major man made contribution to this is the Corps of Engineers keeping the Mississippi from re routing the main channel to the Atchafalaya River basin. Allowing that shift would be a disaster for New Orleans and Baton Rouge. Those ports would no longer have deep enough water to host shipping. Fresh water would be scarce and Billions in infrastructure would be made obsolete.

Aug 06, 2014 10:23am EDT  --  Report as abuse
michaelryan wrote:
another instance of humankind affecting the environment..

Aug 06, 2014 10:57am EDT  --  Report as abuse
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