Massive dead zone may be intensified by oil

By by Katie Moore / Eyewitness News
12 October 2010

NEW ORLEANS — One of the greatest fears of the BP oil spill was that the oil would cause massive dead zones in the Gulf of Mexico. Right now, just off Louisiana’s coast, two dead zones are in place, including one in an area hit hardest by the oil, Chandeleur Sound. And although the oil may have helped intensify this year’s dead zones, researchers say the spill didn’t cause them.

Images of oil globing up on Louisiana’s coast are crystal clear in most minds. What’s much more muddy is the long-term impact of the oil on Louisiana’s coast.

Long before the spill, scientists began studying a massive dead zone in the Gulf of Mexico that stretches from Texas to the mouth of the Mississippi. It’s an area of low oxygen deep in the water column and it affects organisms’ ability to breathe.

“They flee the area and if they can’t they usually suffocate and die,” said Nancy Rabalais, executive director of the Louisiana Universities Marine Consortium.

Her team of scientists has been studying the dead zone for more than 20 years. This year, she predicted the dead zone would set records.

“We predicted to have a large area of dead zone on the Louisiana shore, about 20,000 square kilometers," Rabalais said. "And that’s exactly what it turned out to be. However, we would’ve had more if it weren’t for Tropical Storm Bonnie.”

Bonnie churned up the water, spreading the oxygen around in some areas.

Also this year, John Lopez with the Lake Pontchartrain Basin Foundation, discovered a recurring dead zone east of the Mississippi in the Chandeleur Sound.

“That data that we see in 2008, it looks very similar to what we’re seeing now. We think in 2008, there was the same dead zone that was present,” Lopez said.

This year, Lopez said it’s larger, possibly because of the oil spill.

“We know that the oil was in the water. That may have made it larger, its ecologic effects. So, we can’t really rule out that it was affected by the oil spill,” he said.

But both scientists said both dead zones likely have more to do with the Mississippi River than they do the oil spill.

“We have seen oil and we have not seen lower oxygen values than you would normally get,” Rabalais said.

To keep oil away from the river, the Army Corps of Engineers opened some of the river’s fresh water diversions, pushing more river water east of the mouth.

Scientists’ biggest concern now is whether this will continue to happen in the future, and how long dead zones could affect marine life, like crabs and clams.