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Gulf oil leak causing upheaval in marine ecology

Von: Johnny Asia (baying46584@mypacks.net) [Profil]
Datum: 08.06.2010 23:09
Message-ID: <gact06dlba07p54pbf4ra0ivfvk9l423mn@4ax.com>
Newsgroup: alt.rush-limbaugh alt.politics.usa alt.politics alt.fan.rush-limbaugh alt.politics.liberalismtalk.politics.misc
http://www.newscientist.com/article/dn19021-gulf-oil-leak-causing-upheaval-in-marine-ecolo
gy.html?DCMP=OTC-rss&nsref=environment

Gulf oil leak causing upheaval in marine ecology

*   08 June 2010 by Phil McKenna

As oil continues to leak out of the collapsed Deepwater Horizon well
head, researchers are beginning to collect data on how it is changing
life in the Gulf of Mexico.

Earlier today, Samantha Joye of the University of Georgia in Athens
spoke of what they are finding. She said that methane concentrations
in a giant underwater plume emanating from the well head are as much
as 10,000 times higher than background levels. The consequences of
this for life in the gulf are unknown.

Joye was one of the first scientists to discover deep-water plumes
emanating from the ongoing spill and recently returned from a two-week
research expedition on board the research vessel F. G. Walton Smith.
"It's an infusion of oil and gas that has never been seen before,
certainly not in human history," she said earlier today, as she
described her preliminary findings.

The plume is more than 24 kilometres long, 8 kilometres wide and 90
metres thick, and stretches from 700 to 1300 metres below the surface
south-south-west of the collapsed Deepwater Horizon well head.
Busy bacteria

Joye's team measured oxygen levels throughout the water column near
the plume and found them to be lower than normal, all the way from the
sea floor to the surface. She says this is a result of increased
activity from bacteria that are digesting the oil.

The Gulf of Mexico is no stranger to decreased oxygen levels: every
year, fertilisers pouring off the US coast boost algal growth, which
sucks oxygen out of the water and stifles other life forms, creating
one of the world's largest known dead zones.

Joye said she did not think the extra microbial activity would be
significant enough to create additional dead zones in the gulf,
because microbes need nutrients that do not exist in high enough
concentrations at depth. But she cautions that the environmental
implications are unknown.

"The system as a whole has been substantially perturbed by this
event," says Joye. "When you interfere with the natural system, it's
likely that problems will cascade up the food web."
No end in sight

One big unknown, she says, is how chemical dispersants that are being
injected into the leaking oil to break it up will affect phytoplankton
and other organisms at the bottom of the food chain. In fact, it's
possible  but difficult to prove at this point  that the dispersants
and oil are already killing phytoplankton, which could account for low
oxygen levels recorded in near-surface waters.

And the oil and dispersants are likely to be around for a while yet: a
seasonal change in surface current flows  from north-east to
south-west  that takes effect in August means the mix will continue
sloshing around the gulf rather than be pushed out into the open
ocean.



+

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Johnny Asia, Guitarist from the Future


http://johnnyasia.com


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