It is an overlooked danger in oil spillcrisis: The crude gushing from the well contains vast amounts ofnatural gas that could pose a serious threat to the Gulf ofMexico's fragile ecosystem.
The oil emanating from the seafloor contains about 40 percentmethane, compared with about 5 percent found in typical oildeposits, said John Kessler, a Texas A&M University oceanographerwho 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 humanhistory," Kessler said.
Methane is a colorless, odorless and flammable substance that isa major component in the natural gas used to heat people's homes.Petroleum engineers typically burn off excess gas attached to crudebefore 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 ofcrude from the breached well.
A BP spokesman said the company was burning about 30 millioncubic feet of natural gas daily from the source of the leak, addingup to about 450 million cubic feet since the containment effortstarted 15 days ago. That's enough gas to heat about 450,000 homesfor four days.
But that figure does not account for gas that eluded containmentefforts and wound up in the water, leaving behind huge amounts ofmethane.
BP PLC said a containment cap sitting over the leaking wellfunneled about 619,500 gallons of oil to a drillship waiting on theocean surface on Wednesday. Meanwhile, a specialized flaresiphoning oil and gas from a stack of pipes on the seafloor burnedroughly 161,700 gallons.
Thursday was focused on Capitol Hill, where lawmakers chastisedBP CEO Tony Hayward.
Testifying as oil still surged into the Gulf at between 1.47million and 2.52 million gallons a day, coating more coastal landand marshes, Hayward declared "I am so devastated with thisaccident," "deeply sorry" and "so distraught."
But he also said he was out of the loop on decisions at the welland disclaimed knowledge of any of the myriad problems on and underthe Deepwater Horizon rig before the deadly explosion. BP wasleasing the rig the Deepwater Horizon that exploded April 20,killing 11 workers and triggering the environmental disaster.
"BP blew it," said Rep. Bart Stupak, D-Mich., chairman of theHouse investigations panel that held the hearing. "You cut cornersto save money and time."
As for the methane, scientists are still trying to measure howmuch has escaped into the water and how it may damage the Gulf andit creatures.
The dangerous gas has played an important role throughout thedisaster and response. A bubble of methane is believed to haveburst up from the seafloor and ignited the rig explosion. Methanecrystals also clogged a four-story containment box that engineersearlier 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 theoil and natural gas in the water and are consuming largerquantities of oxygen, which they need to digest food. As they drawmore oxygen from the water, it creates two problems. When oxygenlevels drop low enough, the breakdown of oil grinds to a halt; andas it is depleted in the water, most life can't be sustained.
The National Science Foundation funded research on methane inthe Gulf amid concerns about the depths of the oil plume andquestions what role natural gas was playing in keeping the oilbelow the surface, said David Garrison, a program director in thefederal agency who specializes in biological oceanography.
"This has the potential to harm the ecosystem in ways that wedon't know," Garrison said. "It's a complex problem."
In early June, a research team led by Samantha Joye of theInstitute of Undersea Research and Technology at the University ofGeorgia investigated a 15-mile-long plume drifting southwest fromthe leak site. They said they found methane concentrations up to10,000 times higher than normal, and oxygen levels depleted by 40percent or more.
The scientists found that some parts of the plume had oxygenconcentrations just shy of the level that tips ocean waters intothe category of "dead zone" - a region uninhabitable to fish,crabs, shrimp and other marine creatures.
Kessler has encountered similar findings. Since he began hison-site research on Saturday, he said he has already found oxygendepletions of between 2 percent and 30 percent in waters 1,000 feetdeep.
Shallow waters are normally more susceptible to oxygendepletion. Because it is being found in such deep waters, bothKessler and Joye do not know what is causing the depletion and whatthe impact could be in the long- or short-term.
In an e-mail, Joye called her findings "the most bizarrelooking oxygen profiles I have ever seen anywhere."
Representatives of the National Oceanic and AtmosphericAdministration acknowledged that so much methane in the water coulddraw down oxygen levels and slow the breakdown of oil in the Gulf,but cautioned that research was still under way to understand theramifications.
"We haven't seen any long-term changes or trends at thispoint," said Robert Haddad, chief of the agency's assessment andrestoration division.
Haddad said early efforts to monitor the spill had focusedlargely on the more toxic components of oil. However, as new datacomes in, he said NOAA and other federal agencies will get a moreaccurate read on methane concentrations and the effects.
"The question is what's going on in the deeper, colder parts ofthe ocean," he said. "Are the (methane) concentrations going toovercome the amount of available oxygen? We want to make sure we'renot overloading the system."
BP spokesman Mark Proegler disputed Joye's suggestion that theGulf's deep waters contain large amounts of methane, noting thatwater samples taken by BP and federal agencies have shown minimalunderwater oil outside the spill's vicinity.
"The gas that escapes, what we don't flare, goes up to thesurface and is gone," he said.
Steven DiMarco, an oceanographer at Texas A&M University who hasstudied a long-known "dead zone" in the Gulf, said one example ofmarine life that could be affected by low oxygen levels in deeperwaters would be giant squid - the food of choice for the endangeredsperm whale population. Squid live primarily in deep water, andwould be disrupted by lower oxygen levels, DiMarco said.Copyright © 2014, The Baltimore Sun