- 4028 - UNDERGROUND LIFE - same on other planets? Water trapped below Earth's surface for billions of years could hold keys to unlocking the secrets of extraterrestrial life. It may be where we came from?
------- 4028 - UNDERGROUND LIFE - same on other planets?
- Ancient water trapped
deep within an Alpine mountain range harbors microbial life that might look
quite like that on other planets. In the
depths of this mountain range researchers are searching for life that might
look just like that on other planets.
-
The Bedretto tunnel is a disused access way to a railway tunnel
underneath the imposing Saint-Gotthard mountain range in the Swiss Alps. Deep
within the towering mass of granite, geobiologist Cara Magnabosco collects
samples of water that hasn't seen the light of day for millions of years.
-
- In those samples,
Magnabosco searches for ancient microorganisms that are quite different from
those found on Earth's surface. Unlike
most of today's life, these microorganisms don't need oxygen to survive, which
makes scientists believe that they might look quite like those that first
emerged on our planet over 3.5 billion years ago when Earth's atmosphere had
little oxygen.
-
- These inhabitants of
the wet mountain darkness could teach us about life on other bodies in the
solar system, like Mars or the ice-covered moons of Saturn and Jupiter.
What are the products of a planet when there is no life, like
water-rock reactions, and compare that to the signatures where life is
present. We can study this underground.
We can go to the point where there is no life and look at the products and then
look at how these products change when there is life.
-
-The changes may be barely noticeable. For example, scientists
know that living organisms produce methane. But so do many geological
processes. But the methane that is a byproduct of life may look different than
the purely geological gas.
-
- It may contain different
isotopes, forms of the same chemical element with a different number of
neutrons in their nucleus. Scientists reason that learning to distinguish
between those isotopic differences on Earth will help them develop tools and
techniques to do the same elsewhere in the solar system.
-
- It's not just methane
that can give out a planet's or a moon's secret. There is a whole range of
chemical elements that scientists are interested in, including carbon,
hydrogen, nitrogen, oxygen, phosphorus and sulfur,.
-
- Methane has been
extremely well studied but, for example, sulfate is also really big for
microbiology in these extreme environments.
But also things like nitrates and ammonia, those are all things that
life on Earth uses all the time, they are the key elements of the life cycle.
-
- The water in which
Magnabosco searches for the microbes may at first glance appear just like the
water running from the tap or raining from the sky. But sensitive scientific
instruments reveal that the liquid is, in fact, very different. Trapped miles
below the planet's surface by geological faults and fractures, the ancient
water is saltier and has less oxygen dissolved in it than waters far
above. Scientists can detect more
hydrogen and traces of methane in these subterranean samples.
-
- The water that drips
from the walls of the Bedretto tunnel is no more than 300 million years old,
but elsewhere in the world such as in Canada and South Africa, deeper deposits
have been found that are up to a billion years old. Microbes trapped in such
waters have evolved without contact with the planet's surface for more than a
quarter of the time for which life has existed on Earth.
-
- What we see in this
water as it gets older is that the cell numbers are going down. The microbial
population sizes are decreasing. In
this old water, the amount of living cells per milliliter can be tens of thousands
times lower than what we see in the ocean.
-
- Since conditions on
other bodies in the solar system are unlikely to make it easy for any lifeforms
to survive, geobiologists hope that learning how life operates on the edge of
survivability under Earth's crust will tell them where and how to look for its
traces elsewhere.
-
- The researchers have
found that those creatures dwelling in the depths are not completely different
from the everyday daylight-savoring microbes, however. They are made of similar
types of proteins, and their DNA is so similar to their aboveground
counterparts, in fact, that scientists are quite certain the underground
creatures must be distant cousins of the surface microbes.
-
- The underground
residents are much more similar to those distant ancestors than the much busier
life forms on the planet's surface. While the world underground has barely
changed for billions of years, allowing the microbes to relax into a
predictable existence, conditions on the surface have shifted many times,
forcing organisms to adapt and evolve.
-
- The conditions and the
reactions that are taking place there and driving the organisms living there
are relatively consistent over really long time scales, which is a lot
different than the surface of our planet where we have seen huge changes in
concentrations of oxygen over the billions of years but also changes in ocean
chemistry and the nutrient supply on the surface.
-
- Microbial life may
indeed be waiting to be discovered elsewhere in the solar system. In the
meantime, it turns out we have also had some very alien neighbors right under
our noses this whole time.
May 23, 2023 Underground
Life 4028
-------- Comments
appreciated and Pass it on to whomever is interested. ---
--- Some reviews are
at: -------------- http://jdetrick.blogspot.com -----
-- email feedback,
corrections, request for copies or Index of all reviews
--- to: ------
jamesdetrick@comcast.net
------ “Jim Detrick” -----------
--------------------- ---
Sunday, May 28, 2023
---------------------------------
-
No comments:
Post a Comment