So we see how there are polyextremophiles that can survive multiple
extremes, and by studying these microorganisms,
we can get better understandings of how
microbes tolerate the boundaries of extremes, to
find the boundaries of the earth biosphere.
Why is this of any interest to astrobiologists?
Well, there are really two reasons why we're interested in studying
microbes at extremes, and particularly those
microbes that can tolerate multiple extremes.
First of all, of course, it tells us about the boundaries of the earth's biosphere.
What are the limits
of life on earth? When do we go beyond those limits?
And how might environmental changes throughout the history
of the Earth, even if environmental changes cause
by humans, affect life on earth, and those
microorganisms that inhabit the outer boundaries of the biosphere?
But the other reasons for being interested
in studying life in extreme environments is
because it might give us better ideas
about the habitability of other worlds such as
Mars, Europa, and Enceladus and Titan and
other planetary bodies of interest to astrobiologists.
Once we know the physical conditions on those planetary bodies, we want
to be able to assess whether they are within the boundaries for life.
Whether life might be able to persist on those planetary bodies.
The only way in which we can do that is by
studying microorganisms of life in general in extreme environments, and seeing
whether extremes we observe on other planetary bodies are extremes that
can be tolerated by life forms that we know on the Earth.
So the study of life in extreme environments is essential
for assessing habitability, the ability other planetary bodies to harbor life.