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Posted by: Paolo Amoroso Sep 1 2008, 05:04 PM

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 http://www.repubblica.it. 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

Posted by: djellison Sep 1 2008, 05:32 PM

Well - those numbers do sound high - but let's be realistic about this - Bacteria made it onto Mars with plenty of landers, successful and otherwise, over the past 40 years.

Doug

Posted by: JRehling Sep 1 2008, 05:41 PM

Yes, the problem would only be if they are able to travel away from their sites. If they can't reproduce and/or travel downwind and reproduce in the a location, there's no real harm done.

Of course, if putative martian biota can't travel and reproduce in a new location, then Mars has to be devoid of viable native life.

Posted by: Del Palmer Sep 1 2008, 05:54 PM

I recall reading in Science (or similar rag) that a team from JPL originally found 100,000 microbes per sq/m just a few months before launch, and thus requested a more aggressive sterilization program.

Posted by: 1101001 Sep 1 2008, 06:02 PM

http://www.astrobio.net/news/index.php?name=News&file=article&sid=2338&theme=Printer

Posted by: 1101001 Sep 1 2008, 06:08 PM

New Scientist (so be skeptical): http://space.newscientist.com/article/dn14071-could-microbes-on-phoenix-survive-on-mars.html

This sounds like the source of the Italian story.

Posted by: nprev Sep 1 2008, 06:54 PM

Doug's right, though. You can't get rid of all the little beggars, ever. Mars hasn't been technically pristine since the first thing we sent from Earth arrived.

BTW, didn't one or more of the early Soviet Mars boosters impact Mars as well in the '60s? You KNOW those things weren't even close to sterile. Phoenix & indeed every other lander is squeaky-clean by comparison.

Posted by: Shaka Sep 1 2008, 07:05 PM

Ominous voice of Joe Friday: With a bacterium, it only takes one.
Dummm... de dummdumm....

Posted by: mcaplinger Sep 1 2008, 07:42 PM

The bioburden of the room is fairly irrelevant, as the requirement (<300 spores/m2 for a Class IV Mars lander mission) is obviously on the stuff going to Mars, which is much more extensively cleaned than the room is.

Posted by: ConyHigh Sep 1 2008, 10:17 PM

http://www.youtube.com/watch?v=yjiGH9QNiU0

Ya think there might be some little bugs up there??

Posted by: Pavel Sep 1 2008, 11:00 PM

I think it's Bacillus pumilus (both words ending with "us"). Google easily finds an article mentioning Bacillus pumilus and JPL (Phoenix is not mentioned):
http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0000928
You may prefer to read the PDF version, it looks nicer than the web page.

Posted by: jmknapp Sep 2 2008, 10:46 AM

What's the max surface temperature on Mars--0C? And at the Phoenix site -20C? Any bacteria aren't going anywhere fast.

Posted by: djellison Sep 2 2008, 11:21 AM

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

Doug

Posted by: marsbug Sep 3 2008, 03:07 PM

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 http://www.pnas.org/content/101/13/4631.abstracteven 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 http://www.astrobio.net/news/modules.php?file=index&include=search.php&name=gallery&op=modload&searchstring=cryptoendoliths got carried there, maybe......

Posted by: gallen_53 Sep 3 2008, 05:31 PM

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.

Posted by: marsbug Sep 3 2008, 07:08 PM

Well this conversations been done to the death on every space forum I've ever looked at, so I won't post again on this thread. The main counter-arguments I'd give you for a near surface habitable zone are:

1:Low temperature bacteria I've covered in the links in my last post, they are actually quite common in some places and survive of tiny amounts of water too contaminated with salts to freeze.

2: The atmospheric pressure at the phoenix site is usually above the triple point pressure for water, and any water present at -20 ( which would need to be saturated with a natural antifreeze such as sodium chloride salt) would have a vapour pressure so low it might persist even below that. The pressure needed to give pure water a liquid phase is only 6.7 millibars, and that can be provided by any atmospheric gas, so the absurdly low partial pressure of water in the martian atmosphere doesn't affect the argument. Although in dry air water will evaporate faster it can still form a liquid phase, and at martian polar temperatures I guess evaporation rates would be low even in bone dry air.

3:Most bacterium would be well protected from UV radiation by only a http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6T-41JTRSM-B&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_version=1&_urlVersion=0&_userid=10&md5=60791373d5165ad9b030e46d48b68ecf.

That leaves whatever chemical nasties might be lurking in the soil, and high energy radiation like cosmic rays. For an example of a species that can survive several extreme conditions at once, including dessication, radiation, and oxidising chemicals I give you the absurdly tough http://en.wikipedia.org/wiki/Deinococcus_radiodurans, probably the best know http://en.wikipedia.org/wiki/Polyextremophile but not the only one!

I will point out myself, before I'm embarrassed by someone doing it for me, that even if a microbe might survive on mars if introduced to the right spot, conditions may well still be to harsh for it to grow. Hence the critter wouldn't be able to 'go' anywhere, however as some microbes can metabolise and synthesis proteins at -15 deg c, a warm midsummer day at phoenix's location, I wouldn't rule out very slow reproduction entirely.

Or as I said above, it's right on the edge of possibility, but we've been surprised by micro organisms before...

Edit: I'm sure I've read that there might be a habitable zone in Venus upper cloud layer, but I can't find the article, I'll post a link for you If I can find it.

Posted by: gallen_53 Sep 3 2008, 09:44 PM

You're right, it has been done to death and I'm bored with it. I'll just mention that Deinococcus radiodurans accomplishes its resistance to radiation by having multiple copies of its genome and rapid DNA repair mechanisms. If the bacterium is frozen such that its metabolism has stopped then the radiation damage just accumulates. I don't know if the experiment has ever been performed but I suspect if deinococcus radiodurans is irradiated while frozen then it dies.

Posted by: jmknapp Sep 3 2008, 09:59 PM

You could add:

5. What does it do for food?

I followed the link to the -40C organism & there was something about one cell division every 100 years.

There's a question of whether the metabolic rate (repair processes, etc.) can keep up with spontaneous damage.

Posted by: gallen_53 Sep 4 2008, 12:35 AM

There are altitudes on Venus that border on comfortable, e.g. at 56 km, the pressure is 0.46 bar and the temperature is 18 deg.C. Unfortunately that altitude is in the middle of the sulfuric acid clouds. One could counter argue that there are microbes that LIKE sulfuric acid, e.g. archaea acidophiles. However Venus also has strong atmospheric convection and the whole atmosphere eventually gets convected down to the lower depths where nothing living could survive. This sort of argument also holds for Saturn and Jupiter (atmospheric jellyfish are not really feasible).

Posted by: mike Sep 4 2008, 01:56 AM

Nothing's feasible until it happens.

Posted by: dvandorn Sep 4 2008, 05:22 AM

No, Mike -- feasibility, by definition, is a projection of what is not only possible but actually achievable, based on your best information. Once something happens, feasibility is a dead concept for that phenomenon.

As for life processes, we're going to have to start thinking outside of the box in order to make any major progress in this area, I think. Life sciences are (rather necessarily) very terro-centric right now. For example, even our Martian life experiments all look for organic compounds, and if we don't find any, we state assuredly that there is no possibility of extant life.

Instead of making the (almost definitely false) assumption that any and all life forms in the universe will *always* be made of what we recognize as organic compounds, that it will *all* be powered by ADP-ATP chemical reactions, and that it *all* will require liquid water and free oxygen to become abundant, maybe we need to start asking things like:

What alternative chemical engines to ADP-ATP can be successfully hypothesized?

What other compounds than classic organic compounds could support life processes? Does silicon have enough chemical reactivity to produce living tissues? Does sulphur?

Completely regardless of its chemical composition, what do life processes *do* that we can identify from probes? *Must* it respirate oxygen? *Must* its internal tissues be water-rich? *Must* it reproduce, and how often?

I know some people have been trying to address these issues for decades -- and yet, we still see Mars probes that are designed to look for organic compounds, on the theory that life *must* incorporate the same compounds it does on Earth.

I personally think that one of the first non-terrestrial forms of life we will find will be composed of something other than organic compounds, and all of the textbooks will need immediate and thoroughgoing rewrites!



-the other Doug

Posted by: Shaka Sep 4 2008, 07:06 AM

OK, oDoug, we're all dying to see your detailed proposal for a Mars probe designed to test for these 'alternate' life forms.
Meanwhile, along with our friend Willy of Ockam, we have no alternative but to proceed along these trite paths of inquiry.
(Willy has the funding agencies in his hip pocket.)

Posted by: dvandorn Sep 4 2008, 03:48 PM

Well, Shaka -- just go ask all of Willy's friends who figured all they had to do to reach the Moon was to build a big enough balloon how their assumptions are doing for them these days...

-the other Doug

Posted by: Shaka Sep 4 2008, 08:17 PM

If this were a Science Fiction forum, this issue would offer endless possibilities for heart-felt wrangling, Doug.
But as UMSF professes to be based on science fact, it's not worth wasting the bandwidth, so I'll drop out.
By all means take the last word, and shoot a few more straw men in the process.

Posted by: tedstryk Sep 6 2008, 10:10 PM

I think the source is questionable as well. I mean, it would be like a scientist in the U.S. going to the New York Times or Newsweek to make their claim instead of a scientific journal (or even a press releasefrom their institution with a paper to follow). Yes, sterilization isn't perfect, but I think this is really overhyped.

Posted by: hendric Sep 8 2008, 05:58 PM

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?

Posted by: Juramike Sep 8 2008, 06:31 PM

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. http://en.wikipedia.org/wiki/Strain_121 can survive (and multiply) at autoclave temperature/pressures (major "Oh crap!" revelation for sterilization techniques).

Article on Strain 121 http://www.astrobiology.com/news/viewpr.html?pid=12337 (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.

http://en.wikipedia.org/wiki/Hyperthermophile

-Mike

Posted by: Juramike Sep 9 2008, 08:12 PM

I realize I'm treading a thin line here, but this http://www.space.com/scienceastronomy/080908-space-creature.html was just too interesting and relevant to the discussion to pass up:

According to the article, some tardigrades (water bear) exposed to vacuum, cosmic radiation, and UV radiatoin in a low orbiting satellite survived and were able to reproduce on return to Earth.

So, yeah, transfer, survival in space, and reproduction if the right niche were found, is possible at least for these critters.

-Mike

Posted by: ZenDraken Sep 9 2008, 10:43 PM

One thing we can look for is out-of-equilibrium chemistry. An example is the molecular O2 level in Earth's atmosphere, which is driven by plant respiration. Absent biology it's difficult to figure out how natural processes could sustain a 20% oxygen atmosphere. And forgive me if I'm wrong about this, but as far as I know you don't generally see oxygen floating around all by itself when there's energy and plenty of other stuff it can combine with.

Another example would be Titan's abundance of methane. By no means am I claiming this is evidence of life, but out-of-equilibrium chemistry could be a "flag" for possible life or life-like activity.

Posted by: Juramike Sep 10 2008, 03:33 AM

To get back to the original speculative claim for bacterial contamination from Earth...

IF life is ever detected on Mars, it will require a bit of detective work to determine if life originated on Mars, was inoculated from Earth in the distant past (big impacts on Earth would've splatted some stuff around the solar system), or might've even been inoculated from a recent mission.

If it's an alien biochemistry that's detected (how?), it's a slam-dunk that we didn't do it.

If it's DNA-based stuff, we'll have to do a lot of work to confirm it wasn't instrument contamination, or contamination from a "clean" spacecraft (or a dirty one either!). From articles above, it is "possible" that spores or dormant critters could survive long enough and lay dormant long enough that they could be a possible contaminant in a later experiment. (Although bonus: anything with DNA-repair mechanisms to be able to survive radiation exposure probably wouldn't have a high mutation rate - I'd think a quick genetic check with "usual suspects" would determine if it was originally terrestrial.)

So I'll give the article a "remotely possible" and remember to save any future backflips for detecting martian life for after the DNA results are in.

(Was Huygens sterilized?)

-Mike

Posted by: dvandorn Sep 10 2008, 04:07 AM

But... how are we currently looking (or have any idea how to look for) non-DNA-based life?

Gets back to my earlier post. It appears that every life-detection experiment is *only* looking for life identical to that found on Earth -- DNA-based, made of organic molecules, using the ADP-ATP cycle to generate chemical energy. It's almost a slam-dunk that any life such sensors *do* detect is a result of contamination... isn't it?



-the other Doug

Posted by: 1101001 Sep 10 2008, 04:54 AM

http://saturn.jpl.nasa.gov/faq/huygens.cfm

Posted by: djellison Sep 10 2008, 07:04 AM

But the simple fact is that's the only form of life we understand. It's the only form of life we know of, it's the only form of life that, as of now, we know to exist. At some point, we simply end up having a debate about what constitutes life, would we be able to recognize life significantly different to 'ours'. Sulphur based or Silicon based or whatever-based life - we don't know what reactions that might involve. Will it have something like DNA, will it have something like respiration, will it have something like photosynthesis, what will it do instead of proteins, what will it 'eat', what will it 'poop' - we have absolutely no idea. We've been unable to make carbon based life in the lab - so we're a long long way from perhaps making silicon or some other chemistry based life which we could then observe, measure and understand to the point of knowing how to detect them.

Essentially - we can do the instrument measurements we know of - Xray spec, Mass Spec etc etc ( MSL is very very well equipped in that regard ),we can do that basic elemental and mineralogical characterisation - or we can look for life as we understand it using things such as the Life Marker Chip from here in Leicester. But how can we be expected to identify a different type of life that we've never seen, never measured, have no baseline for, and have no grasp of how it might work.

That's like asking me to find a cow - if I'd never ever seen a cow or heard one described or seen a picture of one. I'd walk straight past the big black and white tree with four legs stood in a field - because I don't know it's a cow.

Posted by: centsworth_II Sep 10 2008, 07:19 AM

No.

Why would you think that "DNA-based, made of organic molecules, using the ADP-ATP cycle" life is exclusive to Earth?

Posted by: tanjent Sep 10 2008, 01:33 PM

In order to positively identify a microscopic life form as being recently imported from Earth I think you would have to do a lot of testing, since we are nowhere near having a complete catalog of Earth species at that level. It might be tough to differentiate it from chemically similar life, based on the same fundamental constituents as our own, that could have ridden in at any time on a meteorite or maybe even originated on Mars before coming to Earth. In that case, if it is just barely holding its own on the red planet, we'd have to worry a lot about contamination, crossbreeding, displacement; maybe even disease as in a reverse "War of the Worlds". And we'd want to study that record for all it was worth because of what it could tell us about our own origins and the implications for panspermia on an even wider scale. Mars' greatest value to us would be as a huge nature preserve - forget about terraforming, colonization, exploitation for the forseeable future. So yeah, it would be a pity to find ourselves in the situation where we couldn't tell the difference between present-day contamination and a truly parallel evolution.

The implication may just be that we should hurry up and get there and do the on-site research while there are still plenty of pristine areas to study. Contamination of an entire unfriendly planet is bound to be a slow business. Life doesn't move around all that rapidly, even in a hospitable environment. Native earthworm species are still busy re-colonizing North America by a few inches each year following the retreat of the most recent glaciers.

In the case of "life" with truly alien constituents, the scope for interaction would likely be much less. If we missed it on the first pass we could probably still find it and identify it after some period of living side-by-side. Some biologists believe that even on Earth alternative life chemistries may simply be carrying on unnoticed amidst the dominant paradigm.

Posted by: vikingmars Sep 10 2008, 02:38 PM

Doug, this is your cow : a Martian rock that resembles remnants of a cow... Well : just found it for fun on a Conspiracy website ! The caption itself worth reading for psycho studies...


[ Caption : "MARTIAN COW
Parallel evolution at work, perhaps this is the remains of a Martian cow. Could they, too, have suffered from Mad Cow Disease? Is that perhaps what killed them?" ]

Posted by: dvandorn Sep 10 2008, 04:27 PM

To Doug et al -- what I'm really getting at, here, I think, is how the Viking results were received. At first, the gas emission results indicated that something was undergoing life-like chemical reactions which caused various liquids and nutrients to be processed and released. However, when the holy grail of organic compounds was not detected, the results were intepreted in the context of "well, since it cannot possibly be caused by any kind of living organism, what exotic chemistry can we postulate that would account for these results?"

In other words, when we placed Martian soil in an environment that would nurture life as we know it, we got results at least roughly consistent with life being present. But when we saw no organic compounds, instead of *also* trying to follow up possible life processes that could exist within the parameters of the observation, the interpretation of the results was shifted such that life-processes were taken off the table as being even remotely possible as the cause.

All I'm saying is that as long as we insist on defining life as *only* that which is based on organic compounds, as long as our definition of life automatically excludes anything except life as it is found on Earth, we are in danger of completely missing other types of life, based on different chemistries. That's really all I'm saying.

And IMHO, the "life question" is important enough that we ought to at least be aware that we're conducting our search with our heads buried in terro-centric sands.

-the other Doug

Posted by: djellison Sep 10 2008, 05:21 PM

I don't think anyone would. We just don't know what else to look for yet. Maybe in 100 years we'll have a wider understanding of what life can be, and then we can go looking for it.

Posted by: ilbasso Sep 10 2008, 05:58 PM

Have we checked any of the big rocks to see if they are actually Hortas?

Posted by: BrianL Sep 10 2008, 06:22 PM

Can they hear a Who?

Posted by: centsworth_II Sep 10 2008, 06:59 PM

How does looking at the Viking reactions from a biological standpoint help? You still have to name the reactants, the reactions and the products. You still need to show that those reactants and products exist. That all can be done without addressing the question of life at all. The problem is there is not enough information.

Posted by: ElkGroveDan Sep 10 2008, 07:04 PM

I wonder if any of http://www.space.com/scienceastronomy/080908-space-creature.html hitched a ride.

Posted by: Shaka Sep 10 2008, 07:59 PM

Complete NONSENSE! You can clearly see the holes in the skull made by the spearpoints of Martian hunters. Just another tragic case of over-exploitation of resources, leading to extinction!

Posted by: imipak Sep 11 2008, 06:46 PM

...rustlers!!

Time to form a posse.

Posted by: PhilCo126 Sep 12 2008, 04:39 PM

those bacteria (if any) will freeze to death once Heimdall crater will be covered in ice and Phoenix Lander entombed like a farao in a few feet of carbon dioxide

Posted by: Juramike Sep 12 2008, 04:52 PM

"those bacteria (if any) will freeze [maybe to death] once Heimdall crater will be covered in ice and Phoenix Lander entombed like a farao in a few feet of carbon dioxide."

Posted by: marsophile Sep 22 2008, 04:37 PM

The bacteria spores may survive a few million years until the next high obliquity period. At that point, conditions should become more favorable, and the bacteria may start to reproduce rapidly. So Mars may have been contaminated, but in slow motion for now...

Posted by: 1101001 Sep 22 2008, 06:09 PM

... at which time, those revived bacteria might find their way to one of the thousands of human garbage dumps on Mars where they can meet up with long-lost relatives in the cozy confines of, say, a disposable diaper or half-eaten meal from a nearby fast-food place.

Posted by: Shaka Sep 22 2008, 09:17 PM

Get a load of the Kim Stanley Robinson-from-Hell! A regular "cock-eyed, rose-glasses optimist" ain't you!
A few million years of human evolution and we'll still have pooey Pampers and Big Macs!
I may throw up.

Posted by: jumpjack Oct 2 2008, 07:26 AM

I wonder if such a kind of life form could actually exist among the thin dust layer and the ice plate below: maybe the 10cm thick dust/sand layer could protect mircobes from ionizing radiation, and missing contact with air could prevent ice from sublimating upon temperature raising?
Maybe this can't happen near poles, but maybe at the equator a very thin melt ice layer could exist among dust layer and ice layer?