Iceland Discovery Promotes Martian Life Hypotheses

nusratt writes "This nature.com article reports research presented at the Bioastronomy 2004 conference in Reykjavik, Iceland. 'Scientists have discovered a community of bacteria living in the lake beneath an Icelandic glacier. The chilly world provides a model of Martian terrain and may boost speculation about the red planet's potential inhabitants. This is the first unequivocal example of life in a subglacial lake. The bacteria were definitely not introduced from above'."

Comments

"Not introduced from above"?!

[Ianoo]

Is the summary serious in the suggestion that these creatures are separately evolved from all the other species on Earth? A totally separate ecosystem with its own spontaneous life-forming process which created original strands of basic RNA/DNA/amino acids as occured for our ancestors in the primeval rock pools of Earth?

I somehow doubt it, for this would be a fairly phenominal discovery. In fact, if you RTFA, this isn't what's being suggested at all.

Until we find such an ecosystem, on Earth or elsewhere in the solar system, the probability of life begining on a world with suitable conditions is the most uncertain variable in the Drake equation. This discovery shows that life can survive in such an environment, but it does not show that it can arise.

Re:"Not introduced from above"?!

[spin2cool]

It's fairly obvious that the sumbitter is referring to the fact that the samples aren't contaminated with present-day organisms from the surface that infiltrated during the drilling or collection.

This doesn't at all imply that it's seperately-evolved life, just that it's life that's been isolated for a very long time. These kinds of conditions can often create unique selective pressures. As a result, these organisms could contain novel biochemical pathways.

A good example of a similar situation are geothermal bacteria living in underground hot springs. By finding and studying them, we found the enzymes used in PCR reactions. Without this discovery, DNA fingerprinting and genome sequencing would be much more difficult.

Re:hmmmm

[DarkElf109]

They're very well-read bacteria, if that's the case

NASA has checked this.

[Eevee]

During the Apollo 12 mission, they recovered material from the Surveyor 3 probe. Examination of one of the recovered pieces showed that microbes had survived for over two years on the moon.

While the moon doesn't have an atmosphere worth mentioning for heating the probe during descent, it does become boiling hot during the lunar day. And, considering that you'll want to protect many instruments from extremes of heat, it may actually stay much cooler than 'boiling' inside the probe during the landing.

Living vs evolving.

[noselasd]

You know, there's a diffrence between living in such a hostile
environment and evolving there. I hardly think the life living
under harsh conditions in iceland evolved there. It rather gradually adapted from things living under much 'friendlier' conditions.
Conditions that might never have been present at Mars, allowing life to
start at all.

Re:Nice but...

[sbaker]

In fact, the high temperatures on re-entry for meteorites are over-blown. Only the surface of the rock gets hot, the interior can still be very cold. Rock is a pretty good thermal insulator. Think about it. If you put a 5lb rock into a white hot oven - and took it out again 30 seconds later, the middle would still be cold. It doesn't take many seconds for something at 50 times the speed of sound to travel through a few miles of atmosphere.

Also the outer layers of the rock (which DO get hot) tend to boil away, carrying the heat away in just the way that the heat shields on spacecraft (other than the shuttle) are designed to do.

Critters riding (frozen) in the center of the rock might well thaw out quite gently long after they hit the ground.

Hence, a robust space travelling bug would only need to be able to recover from beeing deeply frozen - it wouldn't have to be able to cope with high temperatures at any point in its journey.