Giant Plumes of Oil Forming Under the Gulf

[Cees Binkhorst]

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Olie '10 miles long, 3 miles wide and 300 feet thick in spots' en andere
bronnen spreken van een Exxon Valdez per 4 dagen.
Lijkt toch wel op een zéééér grote ramp?

Groet / Cees

May 15, 2010
Giant Plumes of Oil Forming Under the Gulf
http://www.nytimes.com/2010/05/16/us/16oil.html
By JUSTIN GILLIS

Scientists are finding enormous oil plumes in the deep waters of the
Gulf of Mexico, including one as large as 10 miles long, 3 miles wide
and 300 feet thick in spots. The discovery is fresh evidence that the
leak from the broken undersea well could be substantially worse than
estimates that the government and BP have given.

“There’s a shocking amount of oil in the deep water, relative to what
you see in the surface water,” said Samantha Joye, a researcher at the
University of Georgia who is involved in one of the first scientific
missions to gather details about what is happening in the gulf. “There’s
a tremendous amount of oil in multiple layers, three or four or five
layers deep in the water column.”

The plumes are depleting the oxygen dissolved in the gulf, worrying
scientists, who fear that the oxygen level could eventually fall so low
as to kill off much of the sea life near the plumes.

Dr. Joye said the oxygen had already dropped 30 percent near some of the
plumes in the month that the broken oil well had been flowing. “If you
keep those kinds of rates up, you could draw the oxygen down to very low
levels that are dangerous to animals in a couple of months,” she said
Saturday. “That is alarming.”

The plumes were discovered by scientists from several universities
working aboard the research vessel Pelican, which sailed from Cocodrie,
La., on May 3 and has gathered extensive samples and information about
the disaster in the gulf.

Scientists studying video of the gushing oil well have tentatively
calculated that it could be flowing at a rate of 25,000 to 80,000
barrels of oil a day. The latter figure would be 3.4 million gallons a
day. But the government, working from satellite images of the ocean
surface, has calculated a flow rate of only 5,000 barrels a day.

BP has resisted entreaties from scientists that they be allowed to use
sophisticated instruments at the ocean floor that would give a far more
accurate picture of how much oil is really gushing from the well.

“The answer is no to that,” a BP spokesman, Tom Mueller, said on
Saturday. “We’re not going to take any extra efforts now to calculate
flow there at this point. It’s not relevant to the response effort, and
it might even detract from the response effort.”

The undersea plumes may go a long way toward explaining the discrepancy
between the flow estimates, suggesting that much of the oil emerging
from the well could be lingering far below the sea surface.

The scientists on the Pelican mission, which is backed by the National
Oceanic and Atmospheric Administration, the federal agency that monitors
the health of the oceans, are not certain why that would be. They say
they suspect the heavy use of chemical dispersants, which BP has
injected into the stream of oil emerging from the well, may have broken
the oil up into droplets too small to rise rapidly.

BP said Saturday at a briefing in Robert, La., that it had resumed
undersea application of dispersants, after winning Environmental
Protection Agency approval the day before.

“It appears that the application of the subsea dispersant is actually
working,” Doug Suttles, BP’s chief operating officer for exploration and
production, said Saturday. “The oil in the immediate vicinity of the
well and the ships and rigs working in the area is diminished from
previous observations.”

Many scientists had hoped the dispersants would cause oil droplets to
spread so widely that they would be less of a problem in any one place.
If it turns out that is not happening, the strategy could come under
greater scrutiny. Dispersants have never been used in an oil leak of
this size a mile under the ocean, and their effects at such depth are
largely unknown.

Much about the situation below the water is unclear, and the scientists
stressed that their results were preliminary. After the April 20
explosion of the Deepwater Horizon, they altered a previously scheduled
research mission to focus on the effects of the leak.

Interviewed on Saturday by satellite phone, one researcher aboard the
Pelican, Vernon Asper of the University of Southern Mississippi, said
the shallowest oil plume the group had detected was at about 2,300 feet,
while the deepest was near the seafloor at about 4,200 feet.

“We’re trying to map them, but it’s a tedious process,” Dr. Asper said.
“Right now it looks like the oil is moving southwest, not all that rapidly.”

He said they had taken water samples from areas that oil had not yet
reached, and would compare those with later samples to judge the impact
on the chemistry and biology of the ocean.

While they have detected the plumes and their effects with several types
of instruments, the researchers are still not sure about their density,
nor do they have a very good fix on the dimensions.

Given their size, the plumes cannot possibly be made of pure oil, but
more likely consist of fine droplets of oil suspended in a far greater
quantity of water, Dr. Joye said. She added that in places, at least,
the plumes might be the consistency of a thin salad dressing.

Dr. Joye is serving as a coordinator of the mission from her laboratory
in Athens, Ga. Researchers from the University of Mississippi and the
University of Southern Mississippi are aboard the boat taking samples
and running instruments.

Dr. Joye said the findings about declining oxygen levels were especially
worrisome, since oxygen is so slow to move from the surface of the ocean
to the bottom. She suspects that oil-eating bacteria are consuming the
oxygen at a feverish clip as they work to break down the plumes.

While the oxygen depletion so far is not enough to kill off sea life,
the possibility looms that oxygen levels could fall so low as to create
large dead zones, especially at the seafloor. “That’s the big worry,”
said Ray Highsmith, head of the Mississippi center that sponsored the
mission, known as the National Institute for Undersea Science and
Technology.

The Pelican mission is due to end Sunday, but the scientists are seeking
federal support to resume it soon.

“This is a new type of event, and it’s critically important that we
really understand it, because of the incredible number of oil platforms
not only in the Gulf of Mexico but all over the world now,” Dr.
Highsmith said. “We need to know what these events are like, and what
their outcomes can be, and what can be done to deal with the next one.”

Shaila Dewan contributed reporting from Robert, La.

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