Melting million-year-old ice to study ancient microbes
Organisms
that thrive in the harshest environments on the
planet, ranging from the dry, frigid desert of Antarctica
to geyser-like hydrothermal vents spewing toxic
chemicals from the ocean floor, called 'extremophiles',
have long fascinated scientists.
Now, researchers from the University of Delaware
and the University of California at Riverside
have thawed ice estimated to be at least a million
years old from above Lake Vostok, an ancient lake
that lies hidden more than two miles beneath the
frozen surface of Antarctica.
Hostile environment:
Their missions is to study
how microbes have survived in the ice and become
adapted to an environment that is eternally dark,
cold and so isolated that food and energy sources
are likely rare and hard to come by.
The Vostok water contains only between 10-100 microbes
per millitre compared to approximately 1 million
microbes per millitre for most lakes. The research,
which is sponsored by the National Science Foundation
is part of the International Polar Year. "It's
some of the coolest stuff I have ever worked on,"
said Craig Cary, professor of marine biosciences
at UD.
We are going to gain access to the genetics
of organisms isolated for possibly as long as 15
million years.
Segments of a tube-like-ice core were thawed
under meticulous, "clean lab" conditions
to prevent accidental contamination.
Join effort:
The segments of ice were cut from an 11,866-foot ice core drilled in 1998
through a joint effort involving Russia, France
and the United States. The core was taken from approximately
two miles below the surface of Antarctica and 656
feet (200 meters) above the surface of Lake Vostok.
We have no direct samples of the lake itself,
only this indirect sampling of the refrozen ice
above it because drilling into the lake without
taking extensive precautions could lead to the lake's
contamination.
The borehole made to collect the ice is filled with
a mixture of jet fuel, kerosene, and CFC's to keep
it from closing Cary noted.
Sine the lake has not hade direct contact
with the surface world for at least 15 million years,
this would be a contamination of one of the most
pristine environments on Earth, he said.
Novel whole genome amplification techniques
will be applied, which provide insight into the
genetic diversity of a community of organisms when
only small numbers of organisms are available, according
to a University of Delaware press release.
Natural furnaces:
In the case of Lake Vostok,
scientists speculate that it stays in a liquid state
under neath miles of ice due to one of the Earth's
natural furnaces-hydrothermal vents.
Superheated water erupts from these cracks in the
sea floor which from where the plates that from
the Earth's crust pull apart.
We hope that by being so isolated for millions
of years, these microorganisms from Vostok will
able to tell us about their life and conditions
through the ages, Cary said.
SOURCE:The Hindu Newspaper Dated: 29 November, 2007.
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