Thanks to Bob Gravino for spotting this fascinating WHOI story:
The Maritime Executive
Monday, January 23, 2011
Mysterious Flotsam in Gulf of Mexico Came from
Deepwater Horizon Rig, Study Finds
Tracking Debris from Damaged Oil Rigs
Could Help Forecast Coastal Impacts in the Future
Shortly after the Deepwater Horizon disaster,
mysterious honeycomb material was found floating
in the Gulf of Mexico and along coastal beaches.
Using state-of-the-art chemical forensics and a bit
of old-fashioned detective work, a research team
led by scientists at Woods Hole Oceanographic
Institution (WHOI) confirmed that the flotsam were
pieces of material used to maintain buoyancy of the
pipe bringing up oil from the seafloor.
The researchers also affirmed that tracking debris
from damaged offshore oil rigs could help forecast
coastal pollution impacts in future oil spills and guide
emergency response efforts-much the way the
Coast Guard has studied the speed and direction
of various floating debris to guide search and rescue
missions. The findings were published Jan. 19 in
Environmental Research Letters.
On May 5, 2010, 15 days after the Deepwater
Horizon explosion, oceanographer William Graham
and marine technicians from the Dauphin Island
Sea Lab were working from a boat about 32 miles
south of Dauphin Island, Ala., when they saw a
6-mile-long, east-west line containing more than
50 pieces of white material interspersed with
sargassum weed. The porous material was uniformly
embedded with black spheres about a centimeter
in diameter. No oil slick was in sight, but there was
a halo of oil sheen around the honeycomb clumps.
Two days later, the researchers also collected similar
samples about 25 miles south of Dauphin Island.
Nobody knew what the material was, with some
hypothesizing at first that it could be coral or other
substance made by marine plants or animals.
Graham sent samples to WHOI chemist Chris Reddy,
whose lab confirmed that the material was not
biological. But the material’s source remained
unconfirmed.
In January 2011, Reddy and WHOI researche
r Catherine Carmichael, lead author of the new study,
collected a piece of the same unknown material of
Elmer’s Beach, Grand Isle, La. In April, 2011, they
found several large pieces, ranging from 3 to 10 feet,
of the honeycomb debris on the Chandeleur Islands
off Louisiana.
Oil on all these samples was analyzed at WHOI using
comprehensive two-dimensional gas chromatography.
The technique identifies the thousands of individual
chemical compounds that comprise different oils from
different reservoirs. The chemistry of the oil on the
debris matched that of oil sampled directly from the
broken pipe from the Macondo well above the Deepwater
Horizon rig.
In addition, one piece of debris from the Chandeleur
Islands retained a weathered red sticker that read
“Cuming” with the numbers 75-1059 below it. Reddy
found a company called Cuming Corporation in Avon,
Mass., which manufactures syntactic foam flotation
equipment for the oil and gas industry. He e-mailed
photos of the specimen to the company, and within
hours, a Cuming engineer confirmed from the serial
number that the foam came from a buoyancy module
from Deepwater Horizon.
“We realized that the foam and the oil were released into
the environment at the same time,” Reddy said. “So we
had a unique tracer that was independent of the oil itself
to chronicle how oil and debris drifted out from the spill
site.”
The scientists overlaid the locations where they found
honeycomb debris on May 5 and 7 with daily forecasts
produced by the National Oceanic and Atmospheric
Administration (NOAA) of the trajectory of the spreading
oil slick. NOAA used a model that incorporated
currents and wind speeds, along with data from planes
and satellites. On both days, the debris was about
6.2 miles ahead of the spreading slick.
The explanation, the scientists said, is the principle of
leeway, a measure of how fast wind or waves push
materials. The leeway for fresh oil is 3 to 3.3 percent,
but the scientists suspected that “the protruding profile
of the buoyant material” acted acting like a sail, allowing
wind to drive it faster than and ahead of the floating oil.
In this case, the flotsam served as a harbinger for the
oncoming slick, but because different materials can have
different leeways, oil spill models may not accurately
forecast where oiled debris will head. “Even a small
deviation in leeway can, over time, results in significant
differences in surface tracks because of typical wind
fields,” the scientists wrote.
The Coast Guard has a long history of calculating the
leeway of various materials, from life jackets to bodies
of various sizes and weights, to improve forecasts of
where the materials would drift if a ship sank or a plane
crashed into the sea. But calculating leeways has not
been standard practice in oil spills.
“We never had solid data to make the case until this
study,” said Merv Fingas, who tracked oil spills for
more than 38 years for Environment Canada, which
is equivalent to the U.S. Environmental Protection
Agency.
“These results,” the study’s authors wrote, “provide
insights into the fate of debris fields deriving from
damaged marine materials and should be incorporated
into emergency response efforts and forecasting of
coastal impacts during future offshore oil spills.”
This research was funded by the National Science
Foundation.
Source: Woods Hole Oceanographic Instutuion: The
Woods Hole Oceanographic Institution is a private,
independent organization in Falmouth, Mass., dedicated
to marine research, engineering, and higher education.
Established in 1930 on a recommendation from the
National Academy of Sciences, its primary mission
is to understand the ocean and its interaction with the
Earth as a whole, and to communicate a basic
understanding of the ocean’s role in the changing global
environment.
Read more in “The Well From Hell,” see Strawberry Hill tags at the top of this page.
