HortYou are asking Brian to do the imp...

Hort

You are asking Brian to do the impossible. There are no natural non-biological earth soil samples. Even dried and sterilized soils may have thin filaments. Practically every soil examined on Earth have microbes of some type or the other

My working hypothesis, in looking at the soil samples from Mars, is that Mars is similar to Earth in that some putative microbes have developed climax biota at or near the surface throughout Mars, from the Viking site to Meridiani to Gusev and now to the Phoenix site.

That biota is visible to us in the SODs, circles, filaments, strings of spheres, blue discolourations around rocks, etc., that we can see, and through the effects they have in producing very friable looking cohesive soil, because it is made up of basically primitive microbes that are too small to be shown up by the OM and earlier MI's.

Again, If Levin's LR experiment did indeed find life on Mars, the above scenario is what would be expected.

The perchlorate story is important in that it opens up the possibility that there might be microbes on Mars that are similar to the ones on Earth that utilize perchlorates as a substrate and this is highly testable in Martian simulation chambers on Earth.

Winston