[Marxism] Additional arguments against Gulf of Mexico optimism
lnp3 at panix.com
Fri Jul 30 07:49:24 MDT 2010
Scientists Find Evidence That Oil And Dispersant Mix Is Making Its
Way Into The Foodchain
by Dan Froomkin
Scientists have found signs of an oil-and-dispersant mix under the
shells of tiny blue crab larvae in the Gulf of Mexico, the first
clear indication that the unprecedented use of dispersants in the
BP oil spill has broken up the oil into toxic droplets so tiny
that they can easily enter the foodchain.
Marine biologists started finding orange blobs under the
translucent shells of crab larvae in May, and have continued to
find them "in almost all" of the larvae they collect, all the way
from Grand Isle, Louisiana, to Pensacola, Fla. -- more than 300
miles of coastline -- said Harriet Perry, a biologist with the
University of Southern Mississippi's Gulf Coast Research Laboratory.
And now, a team of researchers from Tulane University using
infrared spectrometry to determine the chemical makeup of the
blobs has detected the signature for Corexit, the dispersant BP
used so widely in the Deepwater Horizon
"It does appear that there is a Corexit sort of fingerprint in the
blob samples that we ran," Erin Gray, a Tulane biologist, told the
Huffington Post Thursday. Two independent tests are being run to
confirm those findings, "so don't say that we're 100 percent sure
yet," Gray said.
"The chemistry test is still not completely conclusive," said
Tulane biology professor Caz Taylor, the team's leader. "But that
seems the most likely thing."
With BP's well possibly capped for good, and the surface slick
shrinking, some observers of the Gulf disaster are starting to let
down their guard, with some journalists even asking: Where is the oil?
But the answer is clear: In part due to the1.8 million gallons of
dispersant that BP used, a lot of the estimated 200 million or
more gallons of oil that spewed out of the blown well remains
under the surface of the Gulf in plumes of tiny toxic droplets.
And it's short- and long-term effects could be profound.
BP sprayed dispersant onto the surface of the slick and into the
jet of oil and gas as it erupted out of the wellhead a mile
beneath the surface. As a result, less oil reached the surface and
the Gulf's fragile coastline. But more remained under the surface.
Fish, shrimp and crab larvae, which float around in the open seas,
are considered the most likely to die on account of exposure to
the subsea oil plumes. There are fears, for instance, that an
entire year's worth of bluefin tuna larvae may have perished.
But this latest discovery suggests that it's not just larvae at
risk from the subsurface droplets. It's also the animals that feed
"There are so many animals that eat those little larvae," said
Robert J. Diaz, a marine scientist at the College of William and Mary.
Oil itself is of course toxic, especially over long exposure. But
some scientists worry that the mixture of oil with dispersants
will actually prove more toxic, in part because of the still not
entirely understood ingredients of Corexit, and in part because of
the reduction in droplet size.
"Corexit is in the water column, just as we thought, and it is
entering the bodies of animals. And it's probably having a lethal
impact there," said Susan Shaw, director of the Marine
Environmental Research Institute. The dispersant, she said, is
like " a delivery system" for the oil.
Although a large group of marine scientists meeting in late May
reached a consensus that the application of dispersants was a
legitimate element of the spill response, another group, organized
by Shaw, more recently concluded "that Corexit dispersants, in
combination with crude oil, pose grave health risks to marine life
and human health and threaten to deplete critical niches in the
Gulf food web that may never recover."
One particular concern: "The properties that facilitate the
movement of dispersants through oil also make it easier for them
to move through cell walls, skin barriers, and membranes that
protect vital organs, underlying layers of skin, the surfaces of
eyes, mouths, and other structures."
Perry told the Huffington Post that the small size of the droplets
was clearly a factor in how the oil made its way under the crab
larvae shells. Perry said the oil droplets in the water "are just
the right size that probably in the process of swimming or
respiring, they're brought into that cavity."
That would not happen if the droplets were larger, she said.
The oil droplet washes off when the larvae molt, she said -- but
that's assuming they live that long. Larvae are a major food
source for fish and other blue crabs -- "their siblings are their
favorite meal," Perry explained. Fish are generally able to
excrete ingested oil, but inverterbrates such as crabs don't have
Perry said the discovery of the oil and dispersant blobs is very
troubling -- but not, she made clear, because it has any impact on
the safety of seafood in the short run. "Unlike heavy metals that
biomagnify as they go up the foodchain, oil doesn't seem to do
that," she said. Rather, she said, "we're looking at long-term
ecological effects of having this oil in contact with marine
Diaz, the marine scientist from William and Mary, spoke at a
lunchtime briefing about dispersants on Capitol Hill on Thursday.
Dispersant, he explained, "doesn't make the oil go away, it just
puts it from one part of the ecosystem into another."
In this case, he said, "the decision was to keep as much of the
oil subsurface as possible." As a result, the immediate impact on
coastal wildlife was mitigated. But the effects on ocean life, he
said, are less clear -- in part because there's less known about
ocean ecosystems than coastal ones.
"As we go further offshore, as the oil industry has gone offshore,
we find that we know less," he said. "We haven't really been using
oceanic species to assess the risks, and this is a key issue."
(Similar concerns have been expressed about the lack of important
data that would allow scientists to accurately assess the effects
of the spill on the Gulf's sea turtles, whose plight is emerging
as particularly poignant.)
Diaz warned of the danger posed to bluefin tuna -- and also to
"the signature resident species in the Gulf, the shrimp." He noted
that all three species of Gulf shrimp spawn offshore before moving
back into shallow estuaries.
Diaz also expressed concern that dispersed oil droplets could end
up doing great damage to the Gulf's many undersea coral reefs. "If
the droplets agglomerate with sediment," he said, "they could even
settle to the bottom."
Nancy Kinner, co-director of the Coastal Response Center at the
University of New Hampshire, said the use of dispersants in this
spill raises many issues that scientists need to explore, starting
with the effects of long-term exposure. She also noted that
scientists have never studied the effects of dispersants when
they're injected directly into the turbulence of the plume, as
they were here, or at such depth, or at such low temperatures, or
under such pressure.
She also said it will be essential for the federal government to
accurately determine how much oil made it out of the blown well. A
key data point for scientists is the ratio of dispersant to oil,
she said, and "if you don't know the flow rate of the oil, you
don't know what you dispersant to oil ratio is."
After a series of ludicrous estimates, the federal government
settled last month on an official estimate of about 20,000 to
40,000 barrels a day, but BP is widely expected to contest that
figure and some scientists think it is still a low-ball estimate.
There seems to be no doubt that history will record that the use
of dispersants was good for BP, making it harder to tell how much
oil was spilled, and reducing the short-term visible impact. But
what's less clear is whether it will turn out to have been good
for the Gulf.
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