The story appears on

Page A8

June 19, 2010

GET this page in PDF

Free for subscribers

View shopping cart

Related News

Home » World

New threat to Gulf ecosystem

IT is an overlooked danger in the oil spill crisis: The crude gushing from the well contains vast amounts of natural gas that could pose a serious threat to the Gulf of Mexico's fragile ecosystem.

The oil emanating from the seafloor contains about 40 percent methane, compared with about 5 percent found in typical oil deposits, said John Kessler, a Texas A&M University oceanographer who is studying the impact of methane from the spill.

That means huge quantities of methane have entered the Gulf, scientists say, potentially suffocating marine life and creating "dead zones" where oxygen is so depleted that nothing lives.

"This is the most vigorous methane eruption in modern human history," Kessler said.

Methane is a colorless, odorless and flammable substance that is a major component in the natural gas used to heat people's homes. Petroleum engineers typically burn off excess gas attached to crude before the oil is shipped off to the refinery. That's exactly what BP has done as it has captured more than 7.5 million gallons of crude from the breached well.

A BP spokesman said the company was burning about 30 million cubic feet (850,000 cubic meters) of natural gas daily from the source of the leak, adding up to about 450 million cubic feet since the containment effort started 15 days ago. That's enough gas to heat about 450,000 homes for four days.

But that figure does not account for gas that eluded containment efforts and wound up in the water, leaving behind huge amounts of methane. Scientists are still trying to gauge how much has escaped into the water and how it may damage the Gulf.

The dangerous gas has played an important role throughout the disaster and response. A bubble of methane is believed to have burst up from the seafloor and ignited the rig explosion. Methane crystals also clogged a four-story containment box that engineers earlier tried to place on top of the breached well.

Now it is being looked at as an environmental concern.

The small microbes that live in the sea have been feeding on the oil and natural gas in the water and are consuming larger quantities of oxygen, which they need to digest food.

As they draw more oxygen from the water, it creates two problems. When oxygen levels drop low enough, the breakdown of oil grinds to a halt; and as it is depleted in the water, most life can't be sustained.

The National Science Foundation funded research on methane in the Gulf amid concerns about the depths of the oil plume and questions what role natural gas was playing in keeping the oil below the surface, said David Garrison, a program director in the federal agency who specializes in biological oceanography.



 

Copyright © 1999- Shanghai Daily. All rights reserved.Preferably viewed with Internet Explorer 8 or newer browsers.

沪公网安备 31010602000204号

Email this to your friend