Subsurface lithotrophs on Mars?

As the discovery of so-called SLiMEs (Science, 20 October 1995) on
Earth have shown, non-photosynthetic-based ecosystems exist on Earth.
The idea is that hot water reacts with basalt to produce hydrogen,
that can be used by thermophilic micro-organisms in methanogenesis or
sulfate-reduction. I think if we will ever find life on Mars it will
probably be something of this nature. Do we know if there is basalt or
related iron(II)containing rocks under the Martian surface (I would
guess so, since the surface material is mostly iron(III) and there is
probably a core of liquid iron too)? Are Spirit and Opportunity
capable to detect deep underground reservoirs of liquid water? And if
we can localize these, would it be technologically feasible to equip
future unmanned missions with some means to drill up samples (probably
several hundreds of metres deep) and examine them? Would fixation of
radioactive carbon in these samples provide sufficient proof of
metabolic activity?

On 15 Jan 2004 05:34:17 -0800, (Qualibus
in Tenebris) wrote:

As the discovery of so-called SLiMEs (Science, 20 October 1995) on
Earth have shown, non-photosynthetic-based ecosystems exist on Earth.
The idea is that hot water reacts with basalt to produce hydrogen,
that can be used by thermophilic micro-organisms in methanogenesis or
sulfate-reduction. I think if we will ever find life on Mars it will
probably be something of this nature.

I agree.

Do we know if there is basalt or
related iron(II)containing rocks under the Martian surface (I would
guess so, since the surface material is mostly iron(III) and there is
probably a core of liquid iron too)?

Don't know, but I'd be surprised if there wasn't _something_ for a
lithotroph to eat.

Are Spirit and Opportunity
capable to detect deep underground reservoirs of liquid water?

I'm told the answer is: no, but the ESA orbiter is, if the liquid
water is no more than a few kilometers deep.

And if
we can localize these, would it be technologically feasible to equip
future unmanned missions with some means to drill up samples (probably
several hundreds of metres deep) and examine them?

I don't see why not, though it would depend on how deep; I suspect
there are very few if any places on Mars where there's activity going
on that close to the surface.

Would fixation of
radioactive carbon in these samples provide sufficient proof of
metabolic activity?

No. Viking showed that chemical results don't tell you anything about
the presence or absence of life. To prove the presence of life, you
have to culture it in a petri dish and put it under a microscope.
Hopefully our experience with studying lithotrophs on Earth will
provide guidelines for how to do that.

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