Niet alle olie komt gelijk boven drijven

[Cees Binkhorst]

REPLY TO: D66 at nic.surfnet.nl

Een nieuwe complicatie: niet alle olie die lekt uit de Deepwater well
komt gelijk naar boven. Er vormen zich ook enorme slierten onder water.

Hoe gaan die slierten gelokaliseerd en opgevangen worden?

Zijn die slierten emulsies, gevormd door de combinatie van olie met
chemicaliën, die hun eigen gang gaan volgen?

Groet / Cees

May 28, 2010
Scientists Build Case for Undersea Plumes
http://www.nytimes.com/2010/05/29/science/earth/29plume.html
By JUSTIN GILLIS

IN THE GULF OF MEXICO — The ocean caught fire.

As it blazed, a dense column of black smoke rose toward the sky. Oily
water, the color of strong tea, slopped up the sides of boats. The
breeze carried an acrid smell, like gasoline fumes.

Aboard the research vessel F.G. Walton Smith, anxiety was growing.

Five scientists and six students had come to study the oil leak and its
effect on the sea. They brought flasks and gloves, refrigerators and
freezers, tiny tools and huge cylinders of gas.

They were not looking for oil on the surface, where it was so thick in
places that it was being burned off, but for plumes of fine oil droplets
far beneath the waves.

The stakes were high. Two weeks earlier, when some of these scientists
had disclosed evidence of undersea oil plumes, their claim had been
greeted skeptically by the government. The scientists’ credibility was
on the line.

If the plumes did exist, much of the wisdom about combating oil spills
might need to be reconsidered. The plumes would suggest that any future
oil leak in deep water could be expected to do much of its damage in the
sea, not on shore.

But where were the plumes?

After a slow start, American science is finally beginning to tackle the
oil disaster in earnest. The National Oceanic and Atmospheric
Administration, the federal agency charged with monitoring the health of
the oceans, is sending multiple boats into the gulf. The National
Science Foundation, another arm of the government, is issuing rapid
grants to finance academic teams, including the one aboard the Walton
Smith. BP, the oil company responsible for the spill, has pledged $500
million for research. And scientists like those aboard the Walton Smith
are getting emergency financing from the government for their studies.

This stepped-up effort is starting to bear fruit. This week, another
research vessel confirmed the existence of a huge undersea plume. And on
Thursday, a team of scientists appointed by the Obama administration
offered a more credible estimate of the flow rate at the broken well,
putting it at two to four times the previous calculation.

That higher estimate only added to the sense among academic scientists
that much of the oil must be hovering in the deep sea, instead of
surfacing. The goal of the researchers aboard the Walton Smith was to
nail the existence of such deep-sea plumes beyond any doubt.

They sailed early this week from Gulfport, Miss., and went back to the
spot where they had originally discovered a large plume. It was no
longer there.

All one afternoon, the Walton Smith hopscotched across the gulf. The top
scientists on board, Samantha Joye of the University of Georgia and
Vernon Asper of the University of Southern Mississippi, peered intently
at instrument readouts, hoping for a signal.

Down to the bottom of the sea went a huge apparatus designed to test the
water and grab samples of it. The results kept coming up clean.

Then, late in the afternoon of the second day at sea, the entire
scientific crew suddenly leapt to attention.

The boat had arrived at a new sampling site, west of the oil leak, and
the instruments were traveling once again to the bottom. In a clean
ocean, they would be expected to produce fairly straight lines on a graph.

Instead, wild squiggles were showing up. The display looked like one of
those seismograph readings taken in the throes of an earthquake. At
three different depths, the instruments picked up plumes of material
drifting through the deep ocean.

Dr. Asper stood back, arms crossed, watching the squiggles appear. “To
see something like this is a once-in-a-lifetime thing,” he said. “It’s
really remarkable.”

Soon, a giant winch on the rear of the boat hauled special bottles back
from the deep, carrying water samples. The younger researchers rushed to
the rear deck.

Working quickly in a daisy chain, circling the bottles, they filled
small vials and other containers, then hustled back to their makeshift
laboratory on the main deck of the Walton Smith.

Over the next few hours, they filtered some of the water. They shook
some samples. They stirred some. They pickled some. They bubbled gases
through the water. They refrigerated some vials. They froze some more.

Then they got ready to do it all again.

Within a day, word would come that a separate university vessel, the
Weatherbird II, had discovered a giant plume stretching in the other
direction from the broken well, toward Mobile Bay. That one threatens
some of the finest fishing territory in the gulf.

It will take weeks of laboratory work to confirm with certainty that the
plumes are made of oil droplets, or more likely, some complex mixture of
oil and natural gas. If that idea holds up, the existence of these
undersea plumes may well turn out to be the major scientific discovery
of the great oil spill of 2010.

It could take years for scientists to assess the deep-sea damage fully,
if that is even possible. Among other problems, gulf researchers have
long been hobbled by a critical shortage of vessels equipped for
oceanography.

Only a handful of such ships ply the Gulf of Mexico, and the
best-outfitted boats tend to work for the oil industry. Exploring and
protecting the gulf has simply not been as high a national priority as
drilling it for oil.

Still uncertain are the fates of deep coral reefs that live in the gulf,
as well as the condition of a unique cluster of bottom-dwelling
organisms only nine miles from the damaged well. The ultimate impact the
spill will have on commercially important fish like tuna and snapper is
anyone’s guess.

As the week wore on, the Joye-Asper team found more and more evidence
for the existence of the plumes.

The water samples they pulled up suggested that any oil in the plumes
was highly diffuse — not even visible to the naked eye. But when several
gallons of the water were forced through a fine filter, tiny black oil
droplets appeared.

Even in that diffuse form, the plumes were having a drastic impact on
the chemistry of the ocean, with dissolved oxygen levels plunging as
each plume drifted through the sea.

That, Dr. Joye said, was most likely because bacteria were ramping up to
consume the oil and gas — a good thing, over all, but it was creating a
heavy demand for oxygen and other nutrients. Aside from the toxic effect
of the oil, the declining oxygen was a potential threat to sea life.

Slowly, as the Walton Smith and other boats worked the gulf this past
week, the weird physics of a deep-water well blowout came into better
focus. The idea that oil rises quickly to the surface of an ocean may be
one of the casualties of this disaster.

“Nothing really makes sense out here,” Dr. Joye said as her ship plowed
through orange slicks of oil. “I don’t know that you can necessarily
trust your intuition.”

 From the bridge of the ship, Capt. Shawn Lake made an announcement.
Everyone rushed to the outside decks.

Once again, in the middle distance, the ocean was burning.

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