[Coral-List] Corexit 9500 and corals

Bill Allison allison.billiam at gmail.com
Thu May 20 09:51:04 EDT 2010

Insofar as accurate assessment of the magnitude and nature of oil masses
adrift in the Gulf have consequences for coral reef systems this, abstracted
from todays NY Times (link at end) seems relevant:

Rick Steiner, a marine biologist and a veteran of the 1989 Exxon
.... said the likelihood of extensive undersea plumes of oil
droplets should have been anticipated from the moment the spill began, given
that such an effect from deepwater blowouts had been predicted in the
scientific literature for more than a decade, and confirmed in a test off
the coast of Norway. An extensive sampling program to map and characterize
those plumes should have been put in place from the first days of the spill,
he said.

Ian MacDonald of Florida State
an oceanographer who was among the first to question the official estimate
of 210,000 gallons a day, said he had come to the conclusion that the oil
company was bent on obstructing any accurate calculation. “They want to hide
the body,” he said.

Scientists have long theorized that a shallow spill and a spill in the deep
ocean — this one is a mile down — would behave quite differently. A 2003
report by the National Research
that the oil in a deepwater blowout could break into fine
droplets, forming plumes of oil mixed with water that would not quickly rise
to the surface.

That prediction appeared to be confirmed Saturday when the researchers
aboard the Pelican reported that they had detected immense plumes that they
believed were made of oil particles. The results were not final, and came as
a surprise to the government. They raise a major concern, that sea life in
concentrated areas could be exposed to a heavy load of toxic materials as
the plumes drift through the sea.


Also check this weeks Nature for two articles on the topic.


On Thu, May 20, 2010 at 12:30 AM, Carys Mitchelmore <mitchelm at umces.edu>wrote:

> Hi,
> I havn't been following very many of the threads lately. But I see
> some people are asking about dispersant toxicity to corals. I would be
> happy to provide my 2 pennies worth on dispersants to corals generally
> (I co-wrote the NRC dispersant effect book in 2005 and wrote the
> section on corals!).
> In addition I carried out a 2 year study (yet to be published although
> the interim reports are available from the funding agency; CRRC UNH)
> specifically on Corexit 9500 on the soft coral Xenia. Bottom line is
> at levels that may be environmentally relevant they were acutely
> toxic, they stopped pulsing (nearly instantly), they lost algae,
> ulcerated (not sure in which order) and with time (or higher doses)
> simply dissolved. Short-time low dose exposures showed delayed effects
> and much reduced growth after one month in recovery. Dispersed oil was
> worse (affected by the dissolved and droplet phases).
> I'd be happy to help with any questions. I would also like to ask
> about the hydrous oxide stated to be in the dispersant? How did you
> find this information?
> Best wishes,
> Carys
> --
> Carys Mitchelmore
> Associate Professor
> University of Maryland Center for Environmental Science
> Chesapeake Biological Laboratory
> PO Box 38
> (1 Williams Street)
> Solomons
> MD 20688
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"reality leaves a lot to the imagination..."  John Lennon

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