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Re: Fwd: Re: Did the K-T impact event seed Titan with life?




On Sun, 19 Mar 2006 15:17:19 -0600 Tim Williams
<twilliams_alpha@hotmail.com> writes:

> Magnetotactic bacteria 
> are 
> extremely interesting in that they are one of the few kinds of 
> bacteria that 
> leave behind "hard-body" fossil remains, in the form of magnetite.  


Some bacteria produce a calcification residue as their calling card.  The
cyanobacteria taxon _Calothrix_ is one such example, although I don't
know if its deposit is easily distinguished from calcification deposits
produced by typical hydrologic processes.  AFAIK, nothing resembling
_Calothrix_-like calcifications have been found in the Alan Hills Mars
meteorite.

I believe that there are also a couple of manganese-depositing bacteria
species as well, but I have long since forgotten their names.

One corollary to the proposed K-T impact "inoculation" of the outer moons
hypothesis is that the Chicxulub impactor struck a shallow marine shelf. 
Therefore, a lot of subsurface marine bacteria (rather than subsurface
terrestrial bacteria) may have been entrained in the fissures of the
Chicxulub rocks that were ejected into space.  This natural selection of
marine taxa over terrestrial taxa may have implications as to whether the
organisms could survive after their space journey is completed.

The "ideal" Earth bacterium to make the journey would be an anaerobic,
spore-producing taxon that thrives in low pH water. [Enceladus' water and
Europa's water are both believed to be slightly acidic to strongly
acidic].

No candidates.

<pb>
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