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By Robert S. Boyd, McClatchy Newspapers Robert S. Boyd, Mcclatchy Newspapers
Mon Mar 8, 3:15 pm ET
WASHINGTON While astronomers scour the skies for signs of life in outer
space, biologists are exploring an enormous living world buried below the
surface of the Earth.
Scientists estimate that nearly half the living material on our planet is
hidden in or beneath the ocean or in rocks, soil, tree roots, mines, oil wells,
lakes and aquifers on the continents.
They call it the "subsurface biosphere," a dark world where the sun and stars
don't shine. Some call it Earth's basement.
"Earth's habitable zone extends to depths of hundreds or thousands of meters,"
Katrina Edwards , a microbiologist at the University of Southern California ,
Los Angeles , told a December conference of the American Geophysical Union in
San Francisco . "The organisms that live in this environment may collectively
have a mass equivalent to that of all of Earth's surface dwellers and may
provide keys to solving major environmental, agricultural and industrial
problems."
For example, geologists are considering whether to store some of the world's
excess carbon dioxide, a major greenhouse gas, in a worldwide network of
crevices below the seafloor.
Scientists say research on "intraterrestrial life" complements astronomers'
hunt for "extraterrestrial life" around other stars and planets. The search for
E.T. starts at home.
"Much that we do in our work to discover and understand the deep biosphere has
relevance to the origin and search for life elsewhere in the universe," Edwards
said by e-mail. "Fundamentally, this is all about life detection. ...Our inner
space is a natural testing ground for outer space."
To advance their understanding of subsurface life, marine geologists are about
to launch three drill ship expeditions to punch holes in the seafloor and
implant long-term scientific "observatories'' linked by cable and satellite to
onshore laboratories.
"We'll be sitting in front of a fire hose of data,'' said Andrew Fisher , a
geophysicist at the University of California in Santa Cruz .
In July, the international Integrated Ocean Drilling Program will send its
high-tech drill ship, the JOIDES Resolution, to the Juan de Fuca Ridge off the
Canadian coast in the Northeast Pacific. In October, the ship will head for the
South Pacific Gyre, a vast rotating pool of water between New Zealand and
Hawaii . Next year, it will pass through the Panama Canal to drill in North
Pond , an undersea valley on the Mid-Atlantic Ridge , a chain of seamounts
between North America and Africa .
Fisher, the chief scientist on the Juan de Fuca expedition, said this summer's
drilling would complete a network of six observatories under the North Pacific
seafloor.
Dyed fluids will be pumped into selected places so scientists can follow the
flow of water and microbes through a maze of subsurface "plumbing." These deep
oceanic aquifers are thought to contain as much water as all the rivers on
Earth.
"It'll be like determining how your home plumbing works by sampling the water
at the taps," Fisher said.
Subsurface biosphere research may shed light on the origin on life on Earth and
the possibility of life on other planets.
"The conditions we see in the sub-seafloor are similar to what conditions may
have been on the early Earth," Fisher said. Similar conditions may exist or
have existed on Mars or the moons of Jupiter.
"It is highly likely that if Mars supports life, it will also be in a deep
biosphere where temperatures are high enough to allow liquid water," John
Parnell , a geologist at the University of Aberdeen, Scotland , told a
conference of planetary scientists last week in The Woodlands, Texas .
Steven D'Hondt, an oceanographer at the University of Rhode Island , will lead
the expedition to the South Pacific Gyre. The JOIDES Resolution will drive
seven holes in the seafloor to study microbial life there.
One objective will be to determine whether deep sea chemicals, such as hydrogen
and sulfur, that don't depend on energy from the sun on Earth's surface can
nourish subsurface microbes.