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TAMPA: Scientists have drilled 2.5 kilometres beneath the seabed and found vast underground forests of “deep life”, including microbes that persist for thousands, maybe millions of years, researchers said on Monday.

Feeding on nothing but the energy from rocks, and existing in a slow-motion, even zombie-like state, previously unknown forms of life are abundant beneath the Earth despite extreme temperatures and pressure.

About 70 percent of Earth’s bacteria and archaea — single-celled organisms with no nucleus — live underground, according to the latest findings of an international collaboration involving hundreds of experts, known as the Deep Carbon Observatory. The findings were made public at a meeting of the American Geophysical Union in Washington. This “deep life” amounts to between 15 and 23 billion tons of carbon, said the DCO, launched in 2009, as it nears the end of its 10-year mission to reveal Earth’s inner secrets.

“The deep biosphere of Earth is massive,” said Rick Colwell, who teaches astrobiology and oceanography at Oregon State University.

He described the team’s findings so far as a “very exciting, extreme ecosystem”. Among them may be Earth’s hottest living creature, Geogemma barossii, a single-celled organism found in hydrothermal vents on the seafloor.

Its microscopic cells grow and replicate at 121 Celsius. “There is genetic diversity of life below the surface that is equal to, but perhaps exceeds that which is at the surface and we don’t know much about it,” Colwell said.

Published in Dawn, December 12th, 2018