In search of an oil plume
Scientists using research tools in new ways to look for signs of oil spreading down below, but have turned up nothing
By HARVEY RICE
HOUSTON CHRONICLE
July 2, 2010, 12:37AM
Smiley N. Pool Chronicle
Monday's sunset as seen from an NOAA research vessel belies the turmoil beneath the Gulf's waves.
ABOARD THE THOMAS JEFFERSON — The 208-foot research vessel Thomas Jefferson slicing through swells off Florida's Gulf Coast this week has been chasing an elusive ghost hatched from the BP well blowout: oil plumes.
The prospects of these monstrous plumes emerged as a frightening character in the Macando well narrative after limited data suggested that underwater plumes might be the size of some of the Great Lakes. But until BP's well blew out April 20, no one had tried developing the technology for finding oil underwater.
For the last five weeks, scientists and the rest of Thomas Jefferson Cmdr. Shepard Smith's crew have been working to develop such a method, using the National Oceanic and Atmospheric Administration vessel designed for mapping the ocean bottom in shallow water.
Scientists haven't found a sure-fire method so far, but they are closer to doing so because of this group's research.
They have found no monster plumes of oil extending dozens or hundreds of miles, as had been feared.
Smith said new data suggest the plumes may be a few miles across. He is reluctant to use the word "plume," preferring "anomaly," because scientists are still awaiting lab results to verify their conclusions.
"I'm not aware of a single sample that shows we found oil underwater," acoustics specialist Lt. Sam Greenaway said.
[ The NOAA must be lying! We know the GOM is filled with giant oil plumes and methane, Why it could explode anytime. ]
Clues in the deep
In the commander's office, Greenaway huddles alongside Smith at computer screens showing dark blue columns turning to purple as they descend toward the ocean depths near where BP's Macando well is spewing oil.
The officers are looking for clues in sonar data gathered a week ago that will help them figure out how to find underwater oil. The Thomas Jefferson and other research ships are inventing techniques as they look for something they don't even know how to describe.
"Is it in tiny droplets?" Greenaway wondered aloud. "Is it in large droplets? Is it emulsified? Is it there at all?"
The Thomas Jefferson was two weeks into a five-month mission to chart hazards to navigation along the Gulf Coast when the Macando well erupted. Worries about underwater plumes arose as the blowout continued to spew millions of gallons of oil into the Gulf.
To confront the disaster, the NOAA converted the Thomas Jefferson into a plume hunter.
NOAA upgraded the ship's sonar and equipped it with a "fish," a device towed behind the ship that can dive and look for a fluorescent light signature given off by oil.
Lt. Denise Gruccio, the executive officer, kept watch on the bridge Wednesday. She recalled that because the ship lacked computer steering assistance, it was difficult to keep it stationary for as long as two hours when the fish was cast deep. "It was nerve-wracking," Gruccio said.
Never done before
The ship had borrowed a "rosette," tubes clustered in a circle resembling a rose. Each tube in the rosette is set to sample water at a certain depth.
Although the crew knew how to operate each one of the devices, no one had ever used them in combination to find oil plumes, Smith said.
"We don't normally do this type of work," Smith said. "Nobody ever does this type of work because this deepwater blowout is an unprecedented challenge."
During its first plume-hunting voyage, the Thomas Jefferson headed for the site of the blowout. But the ship was forced to stand off at a distance of five miles so that its sonar wouldn't interfere with equipment being used in the effort to cap the well.
Weeks later, allowed within a half mile of the blowout, they found data suggesting a wake was forming behind the oil column as it spirals to the surface. Greenaway sat at a computer Wednesday and calculated the top of the column, a blue swath on the screen, as about 3,600 feet wide. A U-shaped bump on the screen indicated the possibility of a wake formed by currents pushing against the plume.
"This tells us where to find the oil," Smith said, because any that broke off into plumes would be pushed in the direction of the wake.
Microbial mystery
He said the wake appeared to extend more than 3,000 feet from the bottom of the 5,000-foot column of oil.
The Thomas Jefferson also found data suggesting that microbes were eating the oil as it moved away from the blowout site. Smith said it appears that microbes are breaking down the oil, but it's not clear what remains after they finish dining.
The ship also discovered that, rather than a river of oil, the plumes are more like clouds of oil droplets being pushed through the depths by currents.
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