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Milorad Zaric
Science
in
the
Scientists Search for Extremophiles
By Ron Fridell
Most extremophiles are microbes,
organisms that are too small
to be seen with the naked eye.
Scientists are finding them in places
where we once thought life could
not exist.
The microbe Panagrolaimus davidi,
found in Antarctica, can survive with
all its body water frozen solid. No
other known living thing can do this.
Fish in Antarctic seas have their own
special way of surviving freezing
temperatures. They produce special
“antifreeze molecules” that keep
the water in their cells from freezing.
One species of extremophiles can
live almost anywhere. Tardigrades,
or water bears, grow no bigger
than 1/16 in. Their plump bodies have
eight legs that end in claws or
discs. They are named for the
way they walk, lumbering along
like bears. Tardigrades can live
in temperatures from –423°F to
+304°F! They can also survive ten
years without water. They even
survived a ten-day journey in space
and produced eggs after the
trip. To survive these extremes,
they go into a state of hibernation,
something like what many real
bears do during winter.
© Manfred Kage/Peter Arnold Images/Photolibrary
To us, all these living conditions
would be harsh, even deadly.
But to extremophiles, super-cold,
super-hot, super-dry, and super-toxic
environments are all just fine.
Tardigrades live over 20,000 ft. up on
Earth’s highest mountains and 13,000 ft.
down in Earth’s deepest oceans.
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1
Courtesy of Craig Cary/University of Delaware
Extremophiles are organisms that
inhabit Earth’s least likely places.
Some live inside rocks or glaciers.
Others live in the deepest oceans,
the saltiest lakes, the hottest
springs, or the most poisonous
ponds. Some can even survive in
the total vacuum of outer space.
The Pompeii Worm
Thousands of feet down in
the Pacific Ocean live Pompeii
(pom-PAY) worms. These 4-inchlong extremophiles make their
homes inside paper-thin tubes
next to openings in the seafloor.
Geysers of super-hot water
gush through these openings.
Scientists sent a mini-submarine
to check the temperature and
found out that the worms live
in 176°F water. How could
they possibly survive? Colonies
of bacteria that look like hair
protect the worms’ bodies from
the heat. The bacteria stay
around because the worms
produce a goo to feed them. This
is a true symbiotic relationship!
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Science in the News
Continued from page 1
Scientists Discover Poison-Loving Bacteria
NASA scientists have discovered
a new kind of life form. “What
we’ve found is a microbe doing
something new—building parts
of itself out of arsenic,” said
Felisia Wolfe-Simon.
© Learning A–Z
The GFAJ-1 in Mono Lake takes
the arsenic from the water into
its cells. It swaps the poison for a
life-giving element—phosphorus.
In doing so, this extreme microbe
turns death into life.
GFAJ-1 microbes
The poison is arsenic, a deadly
element that this microbe turns
into life. Scientists
found the microbe in
the waters of Mono
Lake, a closed-in salt
Mono Lake
lake in Northern
California.
© REUTERS/NASA/AAAS
Wolfe-Simon is an astrobiologist.
She studies life beyond Earth.
With no aliens to study yet, she
looks for new kinds of life forms
on Earth. She and her NASA team
have discovered GFAJ-1, the only
known life form that takes poison
into its cells.
When the water evaporates, it
leaves behind lots of salt and
minerals—including arsenic.
San
Francisco
Los Angeles
Mono Lake
San Diego
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CALIFORNIA
Write About This!
2
Every summer, trillions
of brine shrimp, or
sea monkeys, inhabit
the super-salty waters
of Mono Lake. Two
million migrating
birds stop by to feed
on these extremophiles.
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© Jupiterimages Corporation
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Casey Jones/ © Learning A–Z
Most
science-fiction
video
games, comics, books, and movies
portray aliens as invaders who
have come to take over Earth.
Why do you think writers and
filmmakers so often portray
space aliens as threats instead
of friends? Jot down some
reasons. Then write a short
essay to answer this question.