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marsbug
2013-May-25, 06:01 PM
Hello everyone. I guess a few people here have read the news article reporting bacterium that multiply at minus fifteen degrees centigrade (http://www.sciencedaily.com/releases/2013/05/130523113802.htm) and metabolise at minus twenty- five. Does this affect anyones assumptions on what might constitute a habitable environment? Or is it not really that big a deal?

Noclevername
2013-May-25, 08:20 PM
IMO, it's no bigger a deal than the existence of other extremophiles; Since the bacteria adapted to those conditions, it doesn't reflect at all on the origins of life, the conditions where life can begin, or how often those conditions can lead to life.

Colin Robinson
2013-May-26, 04:02 AM
IMO, it's no bigger a deal than the existence of other extremophiles; Since the bacteria adapted to those conditions, it doesn't reflect at all on the origins of life, the conditions where life can begin, or how often those conditions can lead to life.

I agree that the range of conditions life can adapt to is a different question to the range of conditions life could originate in.

But do we know for certain what conditions prevailed in the ancient habitat where life got started?

Do we really know which organisms later adapted to different conditions, and which didn't need to adapt, because the temperature (and other features) of their habitat never changed much?

And even if life can't originate in what we think of as "extreme" conditions, existence of extremophiles is relevant to the question of possible life on worlds which seem to have been less "extreme" in ancient times than today.

E.g. Whether life could have originated on Mars in ancient times, when the atmospheric pressure and temperature permitted stable bodies of liquid water on the surface, and then later adapted to colder and dryer conditions?

Selfsim
2013-May-26, 10:57 AM
Hello everyone. I guess a few people here have read the news article reporting bacterium that multiply at minus fifteen degrees centigrade (http://www.sciencedaily.com/releases/2013/05/130523113802.htm) and metabolise at minus twenty- five. Does this affect anyones assumptions on what might constitute a habitable environment? Or is it not really that big a deal?If the environment exists on Earth ... then its habitable.
Assumptions are superfluous!

Noclevername
2013-May-26, 11:22 AM
I agree that the range of conditions life can adapt to is a different question to the range of conditions life could originate in.

But do we know for certain what conditions prevailed in the ancient habitat where life got started?

Do we really know which organisms later adapted to different conditions, and which didn't need to adapt, because the temperature (and other features) of their habitat never changed much?

And even if life can't originate in what we think of as "extreme" conditions, existence of extremophiles is relevant to the question of possible life on worlds which seem to have been less "extreme" in ancient times than today.

E.g. Whether life could have originated on Mars in ancient times, when the atmospheric pressure and temperature permitted stable bodies of liquid water on the surface, and then later adapted to colder and dryer conditions?

As I said, all that is no different than the examples of any other extremophiles.

Paul Wally
2013-May-26, 03:05 PM
Hello everyone. I guess a few people here have read the news article reporting bacterium that multiply at minus fifteen degrees centigrade (http://www.sciencedaily.com/releases/2013/05/130523113802.htm) and metabolise at minus twenty- five. Does this affect anyones assumptions on what might constitute a habitable environment? Or is it not really that big a deal?

In relation to Mars I think this presents at least two interesting possibilities:
1) That microbial life might survive within the current Martian permafrost conditions. I'm especially thinking of those areas in the southern mid-latitudes where the gully flows, thought to be briny salt water, were observed.
2) The other possibility is that such an organism could be used to terraform Mars. It will be interesting to test this organism under simulated Martian conditions.

Ara Pacis
2013-May-26, 04:37 PM
Hello everyone. I guess a few people here have read the news article reporting bacterium that multiply at minus fifteen degrees centigrade (http://www.sciencedaily.com/releases/2013/05/130523113802.htm) and metabolise at minus twenty- five. Does this affect anyones assumptions on what might constitute a habitable environment? Or is it not really that big a deal?


The researchers believe however, that such microbes may potentially play a harmful role in extremely cold environments such as the High Arctic by increasing carbon dioxide emissions from the melting permafrost, one of the results of global warming.

I'll put it on my Terraforming Plus list.

FarmMarsNow
2013-May-26, 08:23 PM
2) The other possibility is that such an organism could be used to terraform Mars. It will be interesting to test this organism under simulated Martian conditions. Sounds like an opportunity for fame if you try it and succeed.

marsbug
2013-May-26, 10:35 PM
In relation to Mars I think this presents at least two interesting possibilities:
1) That microbial life might survive within the current Martian permafrost conditions. I'm especially thinking of those areas in the southern mid-latitudes where the gully flows, thought to be briny salt water, were observed.
2) The other possibility is that such an organism could be used to terraform Mars. It will be interesting to test this organism under simulated Martian conditions.

If all this organism requires is ice with enough 'antifreeze' in it to create some liquid veins / pockets in the ice at minus 15 deg C, then doesn't that (only to a first guestimate admittedly) mean quite a lot of Mars is potentially habitable to it? IIRC there is ice within meters of the surface well into latitudes where the temperature can get that high. It would only take a landslide or small impact to expose it to the sun.

transreality
2013-May-27, 01:05 AM
It still requires the extremely briny conditions to keep the water liquid so that it can be used by the organism. These conditions may be available adjacent to frozen terrestrial sea-ice, but are they likely to be possible in an meteorite or asteroid. Since the rock has never had a connection to to a massive sea , that is unlikely. Even if it it, how long could those conditions be maintained without connection to that ocean. In space or in the very tenuous martian atmosphere the liquid water must freeze or will be lost by sublimation.

Colin Robinson
2013-May-27, 02:19 AM
It still requires the extremely briny conditions to keep the water liquid so that it can be used by the organism. These conditions may be available adjacent to frozen terrestrial sea-ice, but are they likely to be possible in an meteorite or asteroid. Since the rock has never had a connection to to a massive sea , that is unlikely. Even if it it, how long could those conditions be maintained without connection to that ocean. In space or in the very tenuous martian atmosphere the liquid water must freeze or will be lost by sublimation.

Here on Earth, very briny conditions are found in salt lakes which are nowhere near the ocean.

I think "fresh" water (i.e. low in salt) is only the norm when the water has recently condensed from water vapor, to form rain, snow etc. The point is that the evaporation-precipitation cycle is a natural equivalent of distilling.

Paul Wally
2013-May-27, 04:39 PM
If all this organism requires is ice with enough 'antifreeze' in it to create some liquid veins / pockets in the ice at minus 15 deg C, then doesn't that (only to a first guestimate admittedly) mean quite a lot of Mars is potentially habitable to it? IIRC there is ice within meters of the surface well into latitudes where the temperature can get that high. It would only take a landslide or small impact to expose it to the sun.

Here's (http://mars.jpl.nasa.gov/mro/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1144) some info from the Mars Reconnaissance Orbiter. The supposed liquid water flows do appear to be correlated with the warmer seasons.

traceur
2013-Jun-03, 03:49 AM
Hello everyone. I guess a few people here have read the news article reporting bacterium that multiply at minus fifteen degrees centigrade (http://www.sciencedaily.com/releases/2013/05/130523113802.htm) and metabolise at minus twenty- five. Does this affect anyones assumptions on what might constitute a habitable environment? Or is it not really that big a deal?

I think it does change something - even if it is far from the optimal environment for pre-life / biogenesis (whatever that might be), geologies need only pockets environmentally friendly enough to support biogenesis before life could evolve to spread further out by adapting to more extreme conditions or even - much like the plankton did to earth's atmosphere before life on land arose - transforming the extreme conditions.

For a plausible scenario using this new information - life might originate in small puddles around the volcanic regions of a planet that otherwise is too cold for liquid water, and with some luck, survive long enough to evolve heat-releasing chemical reactions in order to sustain internal layers of liquid water within a cellular membrane.

Ara Pacis
2013-Jun-04, 07:45 PM
I think it does change something - even if it is far from the optimal environment for pre-life / biogenesis (whatever that might be), geologies need only pockets environmentally friendly enough to support biogenesis before life could evolve to spread further out by adapting to more extreme conditions or even - much like the plankton did to earth's atmosphere before life on land arose - transforming the extreme conditions.

For a plausible scenario using this new information - life might originate in small puddles around the volcanic regions of a planet that otherwise is too cold for liquid water, and with some luck, survive long enough to evolve heat-releasing chemical reactions in order to sustain internal layers of liquid water within a cellular membrane.

Maybe if a puddle is all it takes. Do we know how large a "pocket" needs to be to be produce life?

Colin Robinson
2013-Jun-04, 11:23 PM
Maybe if a puddle is all it takes. Do we know how large a "pocket" needs to be to be produce life?

We don't know. That is, we don't know yet.

Here on Earth, there are not just a lot of individual organisms, there is a complex system of mutual interaction and interdependency as well as competition.

It is certainly conceivable that life could begin in a "pocket"-sized environment and/or continue in one. On the other hand, it is also conceivable that life is a system which either occurs at a global (planet-sized) level, or else doesn't occur at all.

publiusr
2013-Jun-08, 06:14 PM
I seem to remember a magazine article talking about a role for ice--and not just smokers--in the formation of life. I think vorticity may also play a role.
The double helix of the Xenia tornado suction spots makes me wonder if DNA is some vortex after-image

ASTRO BOY
2013-Jun-08, 09:08 PM
I agree that the range of conditions life can adapt to is a different question to the range of conditions life could originate in.

But do we know for certain what conditions prevailed in the ancient habitat where life got started?

Do we really know which organisms later adapted to different conditions, and which didn't need to adapt, because the temperature (and other features) of their habitat never changed much?

And even if life can't originate in what we think of as "extreme" conditions, existence of extremophiles is relevant to the question of possible life on worlds which seem to have been less "extreme" in ancient times than today.

E.g. Whether life could have originated on Mars in ancient times, when the atmospheric pressure and temperature permitted stable bodies of liquid water on the surface, and then later adapted to colder and dryer conditions?


That appears to have summed it up quite nicely.

ASTRO BOY
2013-Jun-08, 09:11 PM
For a plausible scenario using this new information - life might originate in small puddles around the volcanic regions of a planet that otherwise is too cold for liquid water, and with some luck, survive long enough to evolve heat-releasing chemical reactions in order to sustain internal layers of liquid water within a cellular membrane.



A realistic scenario and there are probably many more.

TooMany
2013-Jun-09, 04:11 PM
The fact that life processes can proceed at these low temperatures may also indicate abiogenesis can occur at lower temperatures than we usually assume. However, at lower temperatures it's likely that the process would take longer.

Paul Wally
2013-Jun-13, 05:17 PM
According to a study conducted on alpine lichens and cyanobacteria (http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10081/151_read-3409//year-all/#gallery/5671), these organisms can survive under Martian conditions for 34 days!

Here's an extract:


Article
According to astrobiologist Jean-Pierre de Vera, the results obtained showed that "the terrestrial microorganisms could carry out photosynthesis even under these harsh conditions." The water required for this process is present in the morning and evening of the Martian day, when humidity condenses as precipitation across the surface, and the organisms can absorb it. The lichens prove to be creative survivors, primarily in niches on the surface – in small cracks and gaps. They adapted to the artificial Martian environment and demonstrated the same activity that they would in their natural environment. "If life arose on Mars four billion years ago, it could have remained to the present day in niches."

Selfsim
2013-Jun-13, 09:39 PM
According to a study conducted on alpine lichens and cyanobacteria (http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10081/151_read-3409//year-all/#gallery/5671), these organisms can survive under Martian conditions for 34 days!

Here's an extract:Pity there's nothing like that hangin' out on the rocks on Mars!

Aren't we supposed to believe that the incident radiation on Mars has sterilised the surface?
Well, has it or hasn't it? (These guys should make up their minds!)

What are "Martian conditions"?

TooMany
2013-Jun-13, 11:23 PM
The simulated "Martian conditions" are described fairly clearly in the article. They found that the lichen survived in small cracks and gaps in the simulated surface, where they may be less affected by UV. They do not describe that surface other than to mention rocks. It likely did not include perchlorates.

Selfsim, I don't know where you got your idea about what we are supposed to believe. The only thing you ought to believe is the findings of careful research.

Actually this is an excellent type of experiment to perform. As we learn more about conditions, such simulations can be made more realistic. Of course it establishes nothing about life on Mars, but rather that Earth life of this sort can survive those simulated conditions for over one month. That is remarkable. I would not have expected such viability.

Selfsim
2013-Jun-14, 01:55 AM
The simulated "Martian conditions" are described fairly clearly in the article. They found that the lichen survived in small cracks and gaps in the simulated surface, where they may be less affected by UV. They do not describe that surface other than to mention rocks. It likely did not include perchlorates.Why wouldn't four billion year old life on Mars, not have adapted to the present incident UV radiation on Mars? Why do Martian microorganisms have to seek out cover provided by small cracks, gaps and niches? Why are they not visible underneath recently inspected samples? Why is there no difference in soil chemistry, (ie: complex carbon compounds), between samples taken from underneath surfaces and overturned rocks, and exposed surface samples?



...
Selfsim, I don't know where you got your idea about what we are supposed to believe. The only thing you ought to believe is the findings of careful research.My comment was intended to be directed at the hypothesis that 'sterilising radiation' has destroyed surface organics (delivered by asteroid impacts on Mars) .. which is quite a common mainstream hypothesis, which is actually driving the design of upcoming Mars probes.

I agree that beliefs are optional, but I question the ubiquity of this.


Actually this is an excellent type of experiment to perform. As we learn more about conditions, such simulations can be made more realistic. Of course it establishes nothing about life on Mars, but rather that Earth life of this sort can survive those simulated conditions for over one month. That is remarkable. I would not have expected such viability.Actually, its already known that certain types of algae, aerobic heterotrophic prokaryotes, and spore forming fungi microorganisms from Arctic and Antarctic permafrost sediments, (with ages from 5 -10 thousand years to 2-3 million years) can be found, which contain viable micromycete and bacterial cells. So, this knowledge throws more light on the possible time dimensionality/longevity survival aspects, (even though it assumes terrestrial polar environmental evolution/conditions). We can locate the same general environmental conditions on Mars today. We can even simulate the same soil chemistry, (including the added bonus of perchlorates and low level life/cell counts), to supposedly 'post-dict' life test results obtained from Viking LR tests! What makes this particular test so remarkable at all?

If adaptation strategy analysis is really the focus of the study, why not simply reference the Arctic and Antarctic micro-organisms and their environment as the definitive example?
...

The microorganisms adapted to this environment, primarily in niches in rocks and in fissures and gaps in the simulated Martian soil. This might be an indication that such adaptation strategies would make life possible in niches on the actual surface of Mars as well.
...
"If life arose on Mars four billion years ago, it could have remained to the present day in niches." This is clearly not about transplantation of terrestrial extremophiles to 'niches in rocks and in fissures and gaps' in the real Martian soil to see if they can survive. The inference is about origins of life on Mars, and whilst I agree with your conclusion, (which I underlined above), I do not think that is the impact intended by these researchers.

TooMany
2013-Jun-14, 07:03 PM
Why wouldn't four billion year old life on Mars, not have adapted to the present incident UV radiation on Mars? Why do Martian microorganisms have to seek out cover provided by small cracks, gaps and niches? Why are they not visible underneath recently inspected samples? Why is there no difference in soil chemistry, (ie: complex carbon compounds), between samples taken from underneath surfaces and overturned rocks, and exposed surface samples?

UV radiation is highly damaging to organic chemicals. For life to adapt to it, it would have to be far more complex than single-cellular level. You would need an organism capable of developing, in isolation from UV, some sort of shell opaque to the radiation to subsequently survive exposed on the surface. Probably Mars was not hospitable to life long enough to develop multi-cellular creatures.



Why is there no difference in soil chemistry, (ie: complex carbon compounds), between samples taken from underneath surfaces and overturned rocks, and exposed surface samples?

What tests on Mars have ever demonstrated that? Did you see the hole drilled by Curiosity? A couple of millimeters under the surface it is visibly different in composition.



My comment was intended to be directed at the hypothesis that 'sterilising radiation' has destroyed surface organics (delivered by asteroid impacts on Mars) .. which is quite a common mainstream hypothesis, which is actually driving the design of upcoming Mars probes.

It's hardly a hypothesis that the more intense UV on Mars will kill exposed microorganisms as we know them, it's fact. However, not everything near the surface is fully exposed, i.e. there is shade from rocks, crevices or even grains of sand. Those earthbound experiments showed viability of lichen in a Mars-like environment in cracks and gaps.



Actually, its already known that certain types of algae, aerobic heterotrophic prokaryotes, and spore forming fungi microorganisms from Arctic and Antarctic permafrost sediments, (with ages from 5 -10 thousand years to 2-3 million years) can be found, which contain viable micromycete and bacterial cells. So, this knowledge throws more light on the possible time dimensionality/longevity survival aspects, (even though it assumes terrestrial polar environmental evolution/conditions). We can locate the same general environmental conditions on Mars today. We can even simulate the same soil chemistry, (including the added bonus of perchlorates and low level life/cell counts), to supposedly 'post-dict' life test results obtained from Viking LR tests! What makes this particular test so remarkable at all?

Sorry, I don't understand your point here. What's not remarkable? Are you faulting the original LR tests or subsequent experiments attempting to improve our interpretation of the original Viking LR results.



If adaptation strategy analysis is really the focus of the study, why not simply reference the Arctic and Antarctic micro-organisms and their environment as the definitive example?
...
This is clearly not about transplantation of terrestrial extremophiles to 'niches in rocks and in fissures and gaps' in the real Martian soil to see if they can survive. The inference is about origins of life on Mars, and whilst I agree with your conclusion, (which I underlined above), I do not think that is the impact intended by these researchers.

Perhaps your are reading in motives that aren't there. I don't see any inference made about origins of life on Mars at all. Where do you see that?

All they have claimed to demonstrate is that an organism adapted to cold/dry environments on earth can survive under Mars-like conditions. That is a remarkable result. What are the implications? Perhaps if life did get a start on Mars it could still survive today. They have shown that Mars-like conditions do not absolutely exclude the possibility of present life. Good for them.

Selfsim
2013-Jun-15, 12:50 AM
UV radiation is highly damaging to organic chemicals. For life to adapt to it, it would have to be far more complex than single-cellular level. You would need an organism capable of developing, in isolation from UV, some sort of shell opaque to the radiation to subsequently survive exposed on the surface. Probably Mars was not hospitable to life long enough to develop multi-cellular creatures.Some single celled organisms around today, survived the period in Earth's history where UV would have caused DNA damage (due to the ozone layer not having yet formed). They had to develop enzymes called 'base excision repair enzymes', which broke up thymine dimer bonds (caused by UV exposure). There are modern equivalents of these around today which are used in cellular meiosis and mitosis.

There is nothing to say that such defenses have developed on the surface of Mars, but if we're following an Earth-life model, then the precedent and the evolutionary evidence is there.


What tests on Mars have ever demonstrated that? ..Viking Lander 2 Cycle 3 Notch Rock Labelled Release Experiment. (http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/collsoil.htm#VL2%20Sample%203)


It's hardly a hypothesis that the more intense UV on Mars will kill exposed microorganisms as we know them, it's fact.If the VLx LR results are taken as evidence of metabolism (and the VL2 Cycle 3 results as the control), then UV exposure apparently, has no effect on surface dwelling Martian microbe 'metabolism.'
(It should also be noted that UV exposure mostly inhibits the DNA reproduction process .. not necessarily resulting in cell death).


Sorry, I don't understand your point here. What's not remarkable? Are you faulting the original LR tests or subsequent experiments attempting to improve our interpretation of the original Viking LR results.The point I'm making is that Earth's 'Antarctic laboratory' has already provided more complete evidence demonstrating that Earth-like life can survive in high UV environments. The LR tests on Mars, if taken as evidence of metabolism, (and I'm not necessarily saying they should be .. but staying within that paradigm, the points I've made are consistent within it), already provide realistic empirical evidence, due to their origins coming from a natural exo-habitat, as opposed to from an artifical laboratory environment where artificial assumptions must be made about the environmental conditions.

The lab-tests are thus, not particularly 'remarkable'.

Don J
2013-Jun-15, 04:10 AM
Viking Lander 2 Cycle 3 Notch Rock Labelled Release Experiment. (http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/collsoil.htm#VL2%20Sample%203)

If the VLx LR results are taken as evidence of metabolism (and the VL2 Cycle 3 results as the control), then UV exposure apparently, has no effect on surface dwelling Martian microbe 'metabolism.'

That is not what the Biology Sampling Under Notch Rock was about.
The test made with the soil sample taken under the rock was to test an early hypothesis (UV activating the Martian soil)which was put forward during the Viking mission as an attempt to explain the LR positive results in the "absence" of organics detected by the Viking GCMS.We now know that the GCMS did in fact detect organics (Navarro/Gonzales reanalysis of the Viking GCMS datas)


Biology Sampling Under Notch Rock
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/collsoil.htm#VL2%20Sample%203
To test the possibility that ultraviolet exposure might cause a soil sample to give a positive LR response, a sample from under a rock that had been shielded from sunlight was collected.



Why is there no difference in soil chemistry, (ie: complex carbon compounds), between samples taken from underneath surfaces and overturned rocks, and exposed surface samples?

None of the Martian soil samples were taken from the dusty surface directly exposed to UV light.
They were all taken from digged trench 4 to 5 centimeters deep in the Martian soil.Even the soil sample taken under the -pushed- rock was taken from a trench 2.5 cm deep in that case.
Image Notch Rock Push
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/21b198.htm

Image of the Trench.
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/21b200.htm

Sol 51, Third Biology Sample, from under Notch Rock
http://pds-geosciences.wustl.edu/viking/vl1_vl2-m-lr-2-edr-v1/vl_9010/extras/collsoil.htm#VL2%20Sample%203


The sample from under Notch rock was taken by retracting the collector head to clear away possible contaminating debris, elevating. The boom was then extended and de-elevated to make surface contact. It was then extended into material originally under rock. The backhoe trench is about 7.6 cm wide. The sample trench is about 2.5 cm deep, 9 cm wide, and 42 cm long from tip to rim crest of tailings. The sample was then delivered to the biology processor (Moore et al., 1987).

The rock pushing and sample acquisition event was conducted approximately 1 hour after sunrise. The soil sample was exposed to low angle sunlight for approximately 37 minutes prior to placement in the biology processor. It is estimated that this sample contained at least 90 percent of material from under the rock and thus had been protected from ultraviolet light for a long period of time (Levin and Straat, 1976b). Surface temperature during acquisition was approximately -66C. The sample had a residence time of 2 sols before LR nutrient injection. This sample was used for VL2 cycle 3.

Selfsim
2013-Jun-15, 06:42 AM
If the VLx LR results are taken as evidence of metabolism (and the VL2 Cycle 3 results as the control), then UV exposure apparently, has no effect on surface dwelling Martian microbe 'metabolism.'
(It should also be noted that UV exposure mostly inhibits the DNA reproduction process .. not necessarily resulting in cell death).The test made with the soil sample taken under the rock was to test an early hypothesis (UV activating the Martian soil)which was put forward during the Viking mission as an attempt to explain the LR positive results in the "absence" of organics detected by the Viking GCMS.Agreed and then ..
The data from the under-the-rock sample are, in fact, so similar to those obtained from VL1, cycle 1 (Fig. 1), that the curves are essentially superimposable. They differ somewhat only in detailed diurnal temperature fluctuations, probably because of the different temperature patterns between VL1 and VL2. On VL2, average test cell temperatures were about 3C lower than on VL1, whereas maximum detector temperatures were about 3C lower for the first 4 sols and about the same as those for VL1 for the remaining sols. Comparing the two samples collected for VL2, surface temperatures during the acquisitions were approximately -23C for cycle 1 and -66C for cycle 3. The cycle 1 sample also had a longer residence time in the test cell (3 sols versus 2 sols for cycle 3) before nutrient injection. As with VL1, the higher surface temperatures during collection and longer residence before injection correlate with the higher response. The reason for this apparent correlation is not currently known.Why would the LR response be "essentially superimposable", if the LR results are due to metabolising soil based organics, (which is sensitive to UV exposure)?

(Remember that the VL1: Cycles 1 and 2, were from recent surface drift material .. not subsurface in situ soil like VL2 Cycle 1/2 Beta site 'crusty-cloddy type' material).

Viking Labeled Release Biology Experiment: Interim Results
Gilbert V. Levin and Patricia A. Straat (http://www.gillevin.com/Mars/Reprint77_images/Reprint77.htm)


We now know that the GCMS did in fact detect organics (Navarro/Gonzales reanalysis of the Viking GCMS datas)Word-play (again) .. The GCMS did not detect complex organics. The GCMS detected trace water and low level chlorohydrocarbons. A terrestrial kinematics model was constructed to analyse what might have been happening. Based on that particular model and its assumptions, a possible explanation for what the Viking GCMS may have detected, was derived from a terrestrially based analog/model. The assumptions made in that model have not yet been verified by means of subsequent, direct detections of complex organics in Martian soil(s), by an in situ GCMS which also has the appropriate sensitivity and preparation equipment to make such a measurement viable and unambiguous (SAM QMS/GCMS Wet).


None of the Martian soil samples were taken from the dusty surface directly exposed to UV light.
They were all taken from trench few centimeters deep in the Martian soil.Even the sample taken under the -pushed- rock was taken from a trench 2.5 cm deep in that case.Hmm so the sample from under the rock would not have been exposed to sterilising UV at all and yet:
The data from the under-the-rock sample are, in fact, so similar to those obtained from VL1, cycle 1 (Fig. 1), that the curves are essentially superimposable. (As far as the LR results go, that is).
As mentioned above, the assumed 'metabolising organics' should have been sensitive to UV, therefore some response difference between the two samples would have been expected (as per the LR variations measured across different terrestrial samples is in the model)?

Don J
2013-Jun-15, 07:25 AM
Originally Posted by Don J
The test made with the soil sample taken under the rock was to test an early hypothesis (UV activating the Martian soil)which was put forward during the Viking mission as an attempt to explain the LR positive results in the "absence" of organics detected by the Viking GCMS

Agreed … and then .. Why would the LR response be "essentially superimposable", if the LR results are due to metabolising soil based organics, (which is sensitive to UV exposure)?

Original hypothesis: UV light hitting Mars soil must be the cause of the LR positive results.
Test of the hypothesis: LR analysis of a Martian soil sample taken under a rock protected from the UV light.
Result: The data from the under-the-rock sample are, in fact, so similar to those obtained from VL1, cycle 1 (Fig. 1), that the curves are essentially superimposable.
Conclusion:
Simply put, UV light have nothing to do in the production of the LR positive results as was originally thinked.
After that came the hydrogen peroxide oxidant hypothesis trying to explain the LR positive results...which also failed to produce the Viking LR results.
http://www.gillevin.com/Mars/Reprint91-Schnonbx-images/Reprint91-Schnonbx.htm

Which we have discussed on the other thread
http://cosmoquest.org/forum/showthread.php?143405-Mars-Soil-Resembles-Veggie-Garden-Dirt-Lander-Finds&p=2138323#post2138323





Originally Posted by Don J
We now know that the GCMS did in fact detect organics (Navarro/Gonzales reanalysis of the Viking GCMS datas)

Word-play (again) .. The GCMS did not detect complex organics. The GCMS detected trace water and low level chlorohydrocarbons. A terrestrial kinematics model was constructed to analyse what might have been happening. Based on that particular model and its assumptions, a possible explanation for what the Viking GCMS may have detected, was derived from a terrestrially based analog/model. The assumptions made in that model have not yet been verified by means of subsequent, direct detections of complex organics in Martian soil(s), by an in situ GCMS which also has the appropriate sensitivity and preparation equipment to make such a measurement viable and unambiguous (SAM QMS/GCMS Wet).

It seem that untill now the wet method have not been used yet.But i understand that they have only 9 cups of the stuff so they probably want to keep it until they arrive at the base of mount Sharp.

I will stop the discussion about the Viking LR or the Viking GCMS now.I don't want to be blamed of hijacking the thread.

Paul Wally
2013-Jun-15, 12:50 PM
Pity there's nothing like that hangin' out on the rocks on Mars!

Aren't we supposed to believe that the incident radiation on Mars has sterilised the surface?
Well, has it or hasn't it? (These guys should make up their minds!)

What are "Martian conditions"?

The study is about how long certain organisms from Earth could survive on Mars. It doesn't imply that there's any life on Mars. These are two different questions:
1) Can certain Earth organisms survive on Mars?
2) Is there life on Mars?

Surely you can see the difference.


Why wouldn't four billion year old life on Mars, not have adapted to the present incident UV radiation on Mars? Why do Martian microorganisms have to seek out cover provided by small cracks, gaps and niches? Why are they not visible underneath recently inspected samples? Why is there no difference in soil chemistry, (ie: complex carbon compounds), between samples taken from underneath surfaces and overturned rocks, and exposed surface samples?

So all these questions of yours are then based on question 2, not question 1. Life may never have emerged on Mars in the first place, which then makes the question of why life didn't adapt irrelevant. Also, even if there were life on Mars billions of years ago that doesn't necessarily mean that there's life today, and the question of whether Earth organisms can survive on Mars today doesn't even begin to address that question of whether there was ever any life on Mars.

Selfsim
2013-Jun-15, 10:48 PM
Pity there's nothing like that hangin' out on the rocks on Mars!

Aren't we supposed to believe that the incident radiation on Mars has sterilised the surface?
Well, has it or hasn't it? (These guys should make up their minds!)

What are "Martian conditions"?The study is about how long certain organisms from Earth could survive on Mars. It doesn't imply that there's any life on Mars. No its not .. they only tested for 34 days, so the answer was known before the tests commenced!
These are two different questions:
1) Can certain Earth organisms survive on Mars?
2) Is there life on Mars?

Surely you can see the difference.
..
So all these questions of yours are then based on question 2, not question 1. Life may never have emerged on Mars in the first place, which then makes the question of why life didn't adapt irrelevant.

Also, even if there were life on Mars billions of years ago that doesn't necessarily mean that there's life today, and the question of whether Earth organisms can survive on Mars today doesn't even begin to address that question of whether there was ever any life on Mars. The above (underlined) are all your points .. not the study purposes cited in the article ..

Tilman Spohn, head of the DLR Institute of Planetary Research and scientific coordinator for the Helmholtz Alliance. "This long-term experiment in the Martian simulation chamber and its results are an important step forwards," says Spohn. "It makes the presence of life on Mars more plausible." And the existence of primitive life forms such as microorganisms that can be used to address this hypothesis is only to be expected, in the planetary researcher's opinion: "Humans and fauna make up just a tiny proportion of the entire biomass microorganisms, on the other hand, make up more than 80 percent of it."(Above underlined words): Backward logic, if you ask me ..

"If life arose on Mars four billion years ago, it could have remained to the present day in niches."The above statements made by the researchers are specific to your question #2 and are clearly about origins, subsequent habitability and adaption. The Viking 'life', and subsequent Mars experiments, are the best so far developed, for distinguishing the pertinent constraint categories for terrestrial life survivability in a non-terrestrial (Martian) environment. The only unambiguous test for survival and therefore ultimately, habitability definitions, is to send lichens to an atmosphere exposed Martian terrain, and watch what happens. There are way more variables involved in survivability, than can be hoped to be simulated in a lab.

Paul Wally
2013-Jun-15, 11:52 PM
No its not .. they only tested for 34 days, so the answer was known before the tests commenced!…
Whatever! My main point however is a reponse to the following ridiculous set of remarks:


Pity there's nothing like that hangin' out on the rocks on Mars!

Aren't we supposed to believe that the incident radiation on Mars has sterilised the surface?
Well, has it or hasn't it? (These guys should make up their minds!)

What are "Martian conditions"?

The test was conducted on Earth lifeforms not Martian lifeforms, nor was it a test of whether there is life on Mars or whether life emerged on Mars in the past.


The only unambiguous test for survival and therefore ultimately, habitability definitions, is to send lichens to an atmosphere exposed Martian terrain, and watch what happens. There are way more variables involved in survivability, than can be hoped to be simulated in a lab.

Which important variables did they not take into account? Even if they left something out, it can always be incorporated in a new simulation. There's no reason why survivability of Earth organisms cannot be established in a lab.

Paul Wally
2013-Jun-16, 04:13 PM
I wonder if different extremophile species were combined into a kind of ecosystem, whether that would enhance their overall survivability on Mars.
Surely this would make habitability an even more complex issue.