Re: 500 million year old poo and Oxygen

"Paul Ciszek" <nospam@xxxxxxxxxx> wrote in message
news:e65lso$6n8$1@xxxxxxxxxxxxxxxxxxxx
2) A sort of related question: They have found another sealed
underground ecosystem, in Israel this time, with bacteria as
the "primary producers". Where do such ecosystems get their
oxygen? So far as I know, photosynthesis is the only autotrophic
process that produces free oxygen. Last time I tried to ask
this question, I tried to find an appropriate biology newsgroup
and none of them seemed to fit.

Simply put, very little oxygen is required for some ecosystems. There
are some organisms that survive quite well with no oxygen at all. And, for
many "lower" life forms, oxygen in the 2%-4% range can be enough. In the
process, water can be split, donating hydrogen to biological processes and
releasing oxygen. Of course, plants do this but there are chemical systems
that some bacteria can use to power the chemistry.
Many years back, NASA experimented with raising turtles in 1.5 psi and
found that they adapted quite nicely. There are more organisms that we
suspect that can survive in very low oxygen settings. but some life forms
can exists with none and do well enough because of other methods of
metabolizing.
There are two chemically powered ecosystems I can think of right now
here on Earth. In the first, bacteria survive deep underground in the rock
itself by metabolizing petroleum. Magnetite is the energy donor and
breaking it down provides an electron that goes to the metabolic processes.
Oilmen look for fine grained magnetite as a sign that there is
petroleum, because these organisms live near it underground. No oxygen ever
gets down there and no sunlight ever contributes to the process. it is a
strictly chemically driven ecosystem. We might expect such organisms to
live in the bulk of the rock in planets all through the universe,
considering how hardy these things are. That might be the single most
common form of life anywhere.
The other system that comes to mind is the deep oceanic trenches where
"black smokers" inject energy rich chemicals into the water and feed
colonies of bacteria. These are in turn metabolized by tube worms, shrimp,
and other organisms and little or no oxygen is required to keep some of
these things alive. They are pretty complex to live anaerobic existences
but they manage.
Black smokers, as you may know, are the vents from geothermal heat and
chemicals (like from volcanic processes) where dissolved sulfides and
minerals are brought into solution and create what looks like plumes of
black smoke in the water.
So there is more than one way to skin a cat.


.

Relevant Pages

  • Re: 500 million year old poo and Oxygen
    ... are some organisms that survive quite well with no oxygen at all. ... bacteria survive deep underground in the rock ... itself by metabolizing petroleum. ... "black smokers" inject energy rich chemicals into the water and feed ...
    (sci.geo.geology)
  • Re: Lifes complexity: self-organization, evolution or both?
    ... I don't think one should completely dismiss the idea of ecosystems ... composed of a large number of organisms. ... It seems to me instead that succession as well as such ... communities, ...
    (talk.origins)
  • Re: Lifes complexity: self-organization, evolution or both?
    ... One doesn't ordinarily think of ecosystems as having excess ... composed of a large number of organisms. ... statistical treatment that captures the importance of capstone species. ... help create each others' environments. ...
    (talk.origins)
  • Re: Lifes complexity: self-organization, evolution or both?
    ... One doesn't ordinarily think of ecosystems as having excess ... composed of a large number of organisms. ... there was for instance a natural succession of ecosystems ... assemblage of the lower elevation community. ...
    (talk.origins)
  • Re: Lifes complexity: self-organization, evolution or both?
    ... I don't think one should completely dismiss the idea of ecosystems ... composed of a large number of organisms. ... It seems to me instead that succession as well as such ... communities, ...
    (talk.origins)
Quantcast