World's Most Alkaline Life Forms Found Near Chicago

http://www.geosociety.org/news/pr/03-38.htm

The Geological Society of America
Contact: Ann Cairns
Phone: 303-357-1056; Fax: 303-357-1074


FOR IMMEDIATE RELEASE
TUESDAY, NOVEMBER 4, 2003

World's Most Alkaline Life Forms Found Near Chicago

Sometimes the most extreme environment for life isn't at the bottom of the
ocean or inside a volcano. It's just south of Chicago.

Illinois groundwater scientists have found microbial communities thriving in
the slag dumps of the Lake Calumet region of southeast Chicago where the
water can reach extraordinary alkalinity of pH 12.8. That's comparable to
caustic soda and floor strippers - far beyond known naturally occurring
alkaline environments.

The closest known relatives of some of the microbes are in South Africa,
Greenland and the alkaline waters of Mono Lake, California.

"Other alkaline communities have been found at pHs up to 11," says Illinois
State Water Survey hydrogeologist George Roadcap. "That's sort of the high
end of known natural communities."

Roadcap and his colleagues at the University of Illinois Champaign Urbana
came upon the microbes while studying contaminated groundwater created by
more than a century of industrial iron slag dumping in southern Illinois and
northern Indiana. Roadcap will present details of what appear to be the most
alkaline-tolerant life known to date on Tuesday, Nov. 4 at the annual
meeting of the Geological Society of America in Seattle, WA.

Genetic analyses at one site revealed bacteria related to Clostridium and
Bacillus species. These are found in highly alkaline waters of Mono Lake,
tufa columns in Greenland, and cement-contaminated groundwater in a deep
gold mine in Africa. Some RNA sequences appeared most closely related to
thermophilic, or "heat loving," bacteria found in other parts of the world.
The temperatures of the slag dumps are not extraordinary at all, of course.
In fact they get pretty cold in the winter, driving the pH even higher, says
Roadcap.

At five other sites the dominant microbes belonged to the Proteobacteria
class including a large number from the Comamonadacea family of the beta
subclass. "In high-pH microcosms experiments, one of these microbes is
closely related to a hydrogen oxidizer," said Roadcap. That means the
bacteria exploits the hydrogen given off from the corrosion of metallic iron
slag in water.

Just how the unusual bacteria got to the slag dumps is currently a mystery,
says Roadcap. "I'd hate to hazard a guess," he said, regarding their
origins. One possibility is that local bacteria adapted to the extreme
environment over the last century. Another possibility is that they somehow
got imported.

As for whether the unexpected microbial community has any effect on the
extensive groundwater contamination problem in the slag dumps, "We have not
come to any conclusion about that," says Roadcap. Among the possible harmful
things microbes could do is collect and distribute hazardous materials to
nearby lakes and wetlands. But so far that has not been documented.

Alkaline groundwater in the Lake Calumet region was created when steel slag
was dumped and used to fill in wetlands and lakes. Water and air reacts with
the slag to create lime (calcium hydroxide), driving up the pH. There is an
estimated 21 trillion cubic feet of contaminated industrial fill dumped in
southeast Illinois and northeast Indiana, about half of which is thought to
be slag, Roadcap noted. The slag dumps where the microbial communities were
found resembled filled wetlands and are often devoid of surface vegetation,
he explained.

Microbial Community Found Thriving in Very Alkaline (pH 12-13) Groundwater
Tuesday, November 4, 10:25-10:40 a.m., WSCTC: 602/603/604
Abstract may be viewed at:
gsa.confex.com/gsa/2003AM/finalprogram/abstract_61015.htm

CONTACT INFORMATION

George Roadcap
Illinois State Water Survey
217-333-2210


During the GSA Annual Meeting, Nov. 2-5, contact Ann Cairns at the GSA
Newsroom, Washington State Convention Center and Trade Center, Seattle, for
assistance and to arrange for interviews: 206-219-4615.