1. In ice
that has sealed a salty Antarctic lake for more than 2,800 years, scientists
have found frozen bacteria and algae that returned to life after thawing. The
research may help in the search for life on Mars, which is thought to have
subsurface lakes of ice. 2. A research team led by Peter Doran
of the University of Illinois at Chicago drilled through more than 39 feet ice
to collect samples of bacteria and algae. When Doran's team brought them back
and warmed them up a bit, they sprang back to life. 3. Doran
said the microbes have been age-dated at 2,800 years old, but even older
microbes may live deeper in the ice sheet sealing the lake, and in the briny
water below the ice. That deeper ice and the water itself will be cautiously
sampled in a later expedition that will test techniques that may one day be used
on Mars. 4. Called Lake Vida, the 4.5-square-kilometer body is
one of a series of lakes located in the McMurdo Dry Valleys of Antarctica, some
2,200 kilometers due south of New Zealand. This lake has been known since the
1950s, but people ignored it because they thought it was just a big block of
ice. While at the site for other research in the 1990s, Doran and his colleagues
sent radar signals into the clear ice covering the lake and were surprised to
find that 62 feet below there was a pool of liquid water that was about seven
times more salty than seawater. 5. That prompted the
researchers to return in 1996 with equipment to drill a hole down to within a
few feet of the water layer. At the bottom of this hole, researchers harvested
specimens of algae and bacteria. 6. The searchers will return
in 2004 equipped with instruments that are sterilized. They will then drill
through the full 62 feet of ice and sample some of the briny water from the lake
for analysis. The water specimen will be cultured to see if it contains life.
Specimens from the water are expected to be even older than the life forms
extracted from the ice covering. A．Significance of Testing
Techniques for Sampling Microbes in the Deep Ice Sheet
B．Special Features of Lake Vida C．Later Expedition on
Mars D．2004 Revisit Planned for Collecting Lake Water
Specimens E．Antarctic Frozen Life Sampled and Revived
F．Accidental Discovery of Ice-sealed Lake Water in Antarctica
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A．is found to be a great deal higher than that of seawater
B．was of little scientific value
C．may be older than that collected below 39 feet of ice
D．might have come from Mars
E．is to collect some briny lake water for analysis
F．may return to life sooner than microbes frozen in the surface ice
Scientists ignored Lake Vida because they thought that a lake of ice ______.
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Scientists expect that the life, if found in deeper water below the ice sheet, ______.
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What the scientists will do in 2004 ______.
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The salt concentration in the liquid water of Lake Vida ______.