[permaculture] Scientists identify vast underground ecosystem containing billions of micro-organisms | Science | The Guardian

Lawrence London lfljvenaura at gmail.com
Mon Dec 10 18:10:58 EST 2018


https://www.theguardian.com/science/2018/dec/10/tread-softly-because-you-tread-on-23bn-tonnes-of-micro-organisms

Scientists identify vast underground ecosystem containing billions of
micro-organisms

Global team of scientists find ecosystem below earth that is twice the size
of world’s oceans

Jonathan Watts <https://www.theguardian.com/profile/jonathanwatts>

Mon 10 Dec 2018 10.00 EST Last modified on Mon 10 Dec 2018 15.20 EST

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Results
of the 10-year study suggest 70% of bacteria and archaea exist in the
subsurface of the Earth. Photograph: Rungroj Yongrit/EPA

The Earth is far more alive than previously thought, according to “deep
life” studies that reveal a rich ecosystem beneath our feet that is almost
twice the size of that found in all the world’s oceans.

Despite extreme heat, no light, minuscule nutrition and intense pressure,
scientists estimate this subterranean biosphere is teeming with between
15bn and 23bn tonnes of micro-organisms, hundreds of times the combined
weight of every human on the planet.

Researchers at the Deep Carbon Observatory say the diversity of underworld
species bears comparison to the Amazon or the Galápagos Islands, but unlike
those places the environment is still largely pristine because people have
yet to probe most of the subsurface.

“It’s like finding a whole new reservoir of life on Earth,” said Karen
Lloyd, an associate professor at the University of Tennessee in Knoxville.
“We are discovering new types of life all the time. So much of life is
within the Earth rather than on top of it.”

The team combines 1,200 scientists from 52 countries in disciplines ranging
from geology and microbiology to chemistry and physics. A year before the
conclusion of their 10-year study, they will present an amalgamation of
findings to date before the American Geophysical Union’s annual meeting
opens this week.

Samples were taken from boreholes more than 5km deep and undersea drilling
sites to construct models of the ecosystem and estimate how much living
carbon it might contain.

The results suggest 70% of Earth’s bacteria and archaea exist in the
subsurface, including barbed
<https://microbewiki.kenyon.edu/index.php/Altiarchaeales>*Altiarchaeales
<https://microbewiki.kenyon.edu/index.php/Altiarchaeales>* that live in
sulphuric springs and *Geogemma barossii
<https://microbewiki.kenyon.edu/index.php/Geogemma_barossii>*, a
single-celled organism found at 121C hydrothermal vents at the bottom of
the sea.
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One organism found 2.5km below the surface has been buried for millions of
years and may not rely at all on energy from the sun. Instead, the
methanogen has found a way to create methane in this low energy
environment, which it may not use to reproduce or divide, but to replace or
repair broken parts.

Lloyd said: “The strangest thing for me is that some organisms can exist
for millennia. They are metabolically active but in stasis, with less
energy than we thought possible of supporting life.”

Rick Colwell, a microbial ecologist at Oregon State University, said the
timescales of subterranean life were completely different. Some
microorganisms have been alive for thousands of years, barely moving except
with shifts in the tectonic plates, earthquakes or eruptions.

“We humans orientate towards relatively rapid processes – diurnal cycles
based on the sun, or lunar cycles based on the moon – but these organisms
are part of slow, persistent cycles on geological timescales.”

Underworld biospheres vary depending on geology and geography. Their
combined size is estimated to be more than 2bn cubic kilometres, but this
could be expanded further in the future.

The researchers said their discoveries were made possible by two technical
advances: drills that can penetrate far deeper below the Earth’s crust, and
improvements in microscopes that allow life to be detected at increasingly
minute levels.

The scientists have been trying to find a lower limit beyond which life
cannot exist, but the deeper they dig the more life they find. There is a
temperature maximum – currently 122C – but the researchers believe this
record will be broken if they keep exploring and developing more
sophisticated instruments.

Mysteries remain, including whether life colonises up from the depths or
down from the surface, how the microbes interact with chemical processes,
and what this might reveal about how life and the Earth co-evolved.

The scientists say some findings enter the realm of philosophy and
exobiology – the study of extraterrestrial life.

Robert Hazen, a mineralogist at the Carnegie Institution for Science, said:
“We must ask ourselves: if life on Earth can be this different from what
experience has led us to expect, then what strangeness might await as we
probe for life on other worlds?”


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