Paleontology news

"Earth's habitable zone extends to depths of hundreds or thousands of meters," Katrina Edwards, a microbiologist at the University of Southern California, 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.

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 of 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.