Billion-year-old water could hold clues to life on Earth and Mars
A
UK-Canadian team of scientists has discovered ancient pockets of water, which
have been isolated deep underground for billions of years and contain abundant
chemicals known to support life.
This
water could be some of the oldest on the planet and may even contain life. Not
just that, but the similarity between the rocks that trapped it and those on
Mars raises the hope that comparable life-sustaining water could lie buried
beneath the red planet’s surface.
The
findings, published in Nature today, may force us to rethink which parts of our
planet are fit for life, and could reveal clues about how microbes evolve in
isolation.
Researchers
from the universities of Manchester, Lancaster, Toronto and McMaster analysed
water pouring out of boreholes from a mine 2.4 kilometres beneath Ontario,
Canada.
They
found that the water is rich in dissolved gases like hydrogen, methane and
different forms – called isotopes – of noble gases such as helium, neon, argon
and xenon. Indeed, there is as much hydrogen in the water as around
hydrothermal vents in the deep ocean, many of which teem with microscopic life.
The
hydrogen and methane come from the interaction between the rock and water, as
well as natural radioactive elements in the rock reacting with the water. These
gases could provide energy for microbes that may not have been exposed to the
sun for billions of years.
The
crystalline rocks surrounding the water are thought to be around 2.7 billion
years old. But no-one thought the water could be the same age, until now.
Using
ground-breaking techniques developed at the University of Manchester, the
researchers show that the fluid is at least 1.5 billion years old, but could be
significantly older.
NERC-funded
Professor Chris Ballentine of the University of Manchester, co-author of the
study, and project director, says:
‘We’ve
found an interconnected fluid system in the deep Canadian crystalline basement
that is billions of years old, and capable of supporting life. Our finding is
of huge interest to researchers who want to understand how microbes evolve in
isolation, and is central to the whole question of the origin of life, the
sustainability of life, and life in extreme environments and on other planets.’
Before
this finding, the only water of this age was found trapped in tiny bubbles in
rock and is incapable of supporting life. But the water found in the Canadian
mine pours from the rock at a rate of nearly two litres per minute. It has
similar characteristics to far younger water flowing from a mine 2.8 kilometres
below ground in South Africa that was previously found to support microbes.
Ballentine
and his colleagues don’t yet know if the underground system in Canada sustains
life, but Dr Greg Holland of Lancaster University, lead author of the study
says:
‘Our Canadian colleagues are trying to find out if the water contains life right now. What we can be sure of is that we have identified a way in which planets can create and preserve an environment friendly to microbial life for billions of years. This is regardless of how inhospitable the surface might be, opening up the possibility of similar environments in the subsurface of Mars.‘
Professor
Ballentine, based in Manchester’s School of Earth, Atmospheric and
Environmental Sciences, adds:
‘While
the questions about life on Mars raised by our work are incredibly exciting,
the ground-breaking techniques we have developed at Manchester to date ancient
waters also provide a way to calculate how fast methane gas is produced in
ancient rock systems globally. The same new techniques can be applied to
characterise old, deep groundwater that may be a safe place to inject carbon
dioxide.’
David
Willetts, Minister for Universities and Science, says:
‘This
is excellent pioneering research. It gives new insight into our planet. It
has also developed new technology for carbon capture and storage projects.
These have the potential for growth, job creation and our environment.’
This work was funded by NSERC Discovery and CRC grants, a NERC grant and Deep Carbon Observatory (DCO) support.