Italian magazine claims Phoenix contaminated Mars with terrestrial bacteria Options

[Paolo Amoroso]

I have just read a short story by Alex Saragosa published on issue 1067 (29 Aug 2008, pag. 61) of the italian magazine "il venerdì", a Friday supplement of the major national newspaper la repubblica. The story, titled "I batteri terrestri hanno invaso il pianeta rosso" (terrestrial bacteria have invaded the red planet), claims a group of JPL bilogists analyzed samples from the room where Phoenix was assembled and found 26,000 bacterial cells per square meter from 100 different species, including highly radiation resistant Bacillus pumilis. According to the story, these bacteria may have survived the trip to Mars.

I have never heard anything similar from reliable sources (i.e. anything but la Repubblica) . Any info?


Paolo Amoroso

[djellison]

If you're lucky, at summer, near the equator - maybe 20degC

Doug

[marsbug]

Yes but regions that have those kinds of ground temperatures have little unbound H2O and visa versa. However there hasn't been found a hard lower temperature limit to biological processes as far as I know. Everything just gets slower and slower and activity tails off (even for the hardiest), without ever completely stopping, around -15 to - 20. There is some activity going on even at minus 40 deg C. So it's right down at the edge of couldn't happen, but on an unusually warm day if the right little critter got carried there, maybe......

[gallen_53]

There is some activity going on even at minus 40 deg C. So it's right down at the edge of couldn't happen, but on an unusually warm day if the right little critter got carried there, maybe......

Your little critter must endure the following obstacles on the Martian surface :

1) low temperature
2) no liquid water because the atmospheric pressure is too low
3) strong oxidants like perchlorates
4) ionizing radiation, e.g. secondary cosmic rays and short wavelength ultraviolet

You can probably find some weird extremophile that could survive each of the above obstacles
but is there anything recognized as "life" that can survive all four?

I suspect not.

If life exists on Mars it would have to be deep under the surface (deep dark life metabolizing hydrogen).
I might add that a similiar argument could be invoked for life on Venus, i.e. it's deep under the surface.
However I doubt that we'll have the technology to detect Venusian life anytime soon.

[hendric]

I might add that a similiar argument could be invoked for life on Venus, i.e. it's deep under the surface.

Dumb question, but how would the surface temps be lower than the average atmospheric temperatures above? I understand the heat in the atmosphere comes from the Sun, but wouldn't that "cap" prevent temps below it in the subsurface?

[Juramike]

Dumb question, but how would the surface temps be lower than the average atmospheric temperatures above? I understand the heat in the atmosphere comes from the Sun, but wouldn't that "cap" prevent temps below it in the subsurface?

You are right, the temperature of Venus's subsurface would be "beyond hellish". But the high pressure might allow critters to have some sort of metabolism in a liquid (which one?) phase due to the high pressure.

Some extreme thermophiles on Earth can live above 100 C as long the pressure is enough to prevent boiling. Strain 21 can survive (and multiply) at autoclave temperature/pressures (major "Oh crap!" revelation for sterilization techniques).

Article on Strain 121 here (yet another wonderful thing from the Puget Sound region)

The upper limit for DNA-based life is thought to be around 150 C, due to breakdown of DNA and enzymes (folding of tertiary structure and all that). A biochemistry based on "harder" linkages and "harder" structure holding features (i.e. no wussy hydrogen bonds or cysteine-cysteine linkages) might be possible at higher temperatures.

Wikipedia/Hyperthermophile

-Mike