Curiosity rover finds active, ancient organic chemistry on Mars

December 16, 2014 by Dwayne Brown
This image illustrates possible ways methane might be added to Mars' atmosphere (sources) and removed from the atmosphere (sinks). NASA's Curiosity Mars rover has detected fluctuations in methane concentration in the atmosphere, implying both types of activity occur on modern Mars. Credit: NASA/JPL-Caltech/SAM-GSFC/Univ. of Michigan

(Phys.org)—NASA's Mars Curiosity rover has measured a tenfold spike in methane, an organic chemical, in the atmosphere around it and detected other organic molecules in a rock-powder sample collected by the robotic laboratory's drill.

"This temporary increase in methane—sharply up and then back down—tells us there must be some relatively localized source," said Sushil Atreya of the University of Michigan, Ann Arbor, and Curiosity rover science team. "There are many possible sources, biological or non-biological, such as interaction of water and rock."

Researchers used Curiosity's onboard Sample Analysis at Mars (SAM) laboratory a dozen times in a 20-month period to sniff methane in the atmosphere. During two of those months, in late 2013 and early 2014, four measurements averaged seven parts per billion. Before and after that, readings averaged only one-tenth that level.

Curiosity also detected different Martian organic chemicals in powder drilled from a rock dubbed Cumberland, the first definitive detection of organics in surface materials of Mars. These Martian organics could either have formed on Mars or been delivered to Mars by meteorites.

Organic molecules, which contain carbon and usually hydrogen, are chemical building blocks of life, although they can exist without the presence of life. Curiosity's findings from analyzing samples of atmosphere and rock powder do not reveal whether Mars has ever harbored living microbes, but the findings do shed light on a chemically active modern Mars and on favorable conditions for life on ancient Mars.

"We will keep working on the puzzles these findings present," said John Grotzinger, Curiosity project scientist of the California Institute of Technology in Pasadena (Caltech). "Can we learn more about the active chemistry causing such fluctuations in the amount of methane in the atmosphere? Can we choose rock targets where identifiable organics have been preserved?"

Researchers worked many months to determine whether any of the organic material detected in the Cumberland sample was truly Martian. Curiosity's SAM lab detected in several samples some organic carbon compounds that were, in fact, transported from Earth inside the rover. However, extensive testing and analysis yielded confidence in the detection of Martian organics.

NASA's Mars rover Curiosity drilled into this rock target, "Cumberland," during the 279th Martian day, or sol, of the rover's work on Mars (May 19, 2013) and collected a powdered sample of material from the rock's interior. Credit: NASA/JPL-Caltech/MSSS

Identifying which specific Martian organics are in the rock is complicated by the presence of perchlorate minerals in Martian rocks and soils. When heated inside SAM, the perchlorates alter the structures of the organic compounds, so the identities of the Martian organics in the rock remain uncertain.

"This first confirmation of organic carbon in a rock on Mars holds much promise," said Curiosity participating scientist Roger Summons of the Massachusetts Institute of Technology in Cambridge. "Organics are important because they can tell us about the chemical pathways by which they were formed and preserved. In turn, this is informative about Earth-Mars differences and whether or not particular environments represented by Gale Crater sedimentary rocks were more or less favorable for accumulation of organic materials. The challenge now is to find other rocks on Mount Sharp that might have different and more extensive inventories of organic compounds."

Researchers also reported that Curiosity's taste of Martian water, bound into lakebed minerals in the Cumberland rock more than three billion years ago, indicates the planet lost much of its water before that lakebed formed and continued to lose large amounts after.

SAM analyzed hydrogen isotopes from water molecules that had been locked inside a rock sample for billions of years and were freed when SAM heated it, yielding information about the history of Martian water. The ratio of a heavier hydrogen isotope, deuterium, to the most common hydrogen isotope can provide a signature for comparison across different stages of a planet's history.

"It's really interesting that our measurements from Curiosity of gases extracted from ancient rocks can tell us about loss of water from Mars," said Paul Mahaffy, SAM principal investigator of NASA's Goddard Space Flight Center in Greenbelt, Maryland, and lead author of a report published online this week by the journal Science.

The ratio of deuterium to hydrogen has changed because the lighter hydrogen escapes from the upper atmosphere of Mars much more readily than heavier deuterium. In order to go back in time and see how the deuterium-to-hydrogen ratio in Martian water changed over time, researchers can look at the ratio in water in the current atmosphere and water trapped in rocks at different times in the planet's history.

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Daniel Glavin of NASA's Goddard Space Flight Center discusses the discovery of organic matter on Mars and other recent results from the MSL Curiosity rover. Credit: NASA Goddard

Martian meteorites found on Earth also provide some information, but this record has gaps. No known Martian meteorites are even close to the same age as the rock studied on Mars, which formed about 3.9 billion to 4.6 billion years ago, according to Curiosity's measurements.

The ratio that Curiosity found in the Cumberland sample is about one-half the ratio in water vapor in today's Martian atmosphere, suggesting much of the planet's water loss occurred since that rock formed. However, the measured ratio is about three times higher than the ratio in the original water supply of Mars, based on assumption that supply had a ratio similar to that measured in Earth's oceans. This suggests much of Mars' original was lost before the rock formed.

Curiosity is one element of NASA's ongoing Mars research and preparation for a human mission to Mars in the 2030s. Caltech manages the Jet Propulsion Laboratory in Pasadena, California, and JPL manages Curiosity rover science investigations for NASA's Science Mission Directorate in Washington. The SAM investigation is led by Paul Mahaffy of Goddard. Two of SAM instruments key in these discoveries are the Quadrupole Mass Spectrometer, developed at Goddard, and the Tunable Laser Spectrometer, developed at JPL.

The results of the Curiosity rover investigation into methane detection and the Martian organics in an ancient rock were discussed at a news briefing Tuesday at the American Geophysical Union's convention in San Francisco. The methane results are described in a paper published online this week in the journal Science by NASA scientist Chris Webster of JPL, and co-authors.

A report on organics detection in the Cumberland by NASA scientist Caroline Freissenet, of Goddard, and co-authors, is pending publication.

Explore further: Curiosity rover makes first detection of organic matter on Mars

More information: Mars Methane Detection and Variability at Gale Crater, Science Express, www.sciencemag.org/content/early/2014/12/15/science.1261713.abstract

The Imprint of Atmospheric Evolution in the D/H or Hesperian Clay Minerals on Mars, Science Express, www.sciencemag.org/content/early/2014/12/15/science.1260291.abstract

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baudrunner
5 / 5 (6) Dec 16, 2014
I like how the possibility of methane originating from life beneath the surface, in the form of the anaerobic methanogens, has not been ruled out. If that is the case, we might find hydrocarbon deposits beneath the surface, like oil. The digestion of ferrite substrata by these archaea yields oil as one the processes by which this valuable resource is sourced. The potential ramifications are enormous.
foolspoo
5 / 5 (7) Dec 16, 2014
I like to remind myself of how difficult it is for the human mind to comprehend one billion. dollars/toads/humans/years. regardless of subject, the laymans' mind is not able to grasp the timescales which our universe operates. in just 10 million years, our planet may not be recognizable from a few thousand miles.

it seems to me that these findings are incosequential, initially. as we continue to collect and interpret, we may very well learn that mars did indeed host life in its unfathomably long history. in its own right, these findings are remarkable!
TopCat22
5 / 5 (3) Dec 16, 2014
the question is ... Who farted?
Shootist
3.7 / 5 (3) Dec 16, 2014
It's ghouls I tell ya, religious ghouls. looking for a place to call their own.
sselig
4 / 5 (4) Dec 16, 2014
The more suggestive the evidence becomes that mars might harbor life the more concerned we should be about contamination, particularly if we're serious about getting there ourselves someday. We ought to do everything possible to tease out its secrets before sneezing all over it. Is there a sample-return mission already funded and in the works? If not, there ought to be.
---s
qitana
not rated yet Dec 16, 2014
I was thinking.. perhaps this instrument to measure the amount of methane could be malfunctioning too, but probably not, I do assume
TheGhostofOtto1923
2.3 / 5 (3) Dec 16, 2014
I like how the possibility of methane originating from life beneath the surface, in the form of the anaerobic methanogens, has not been ruled out. If that is the case, we might find hydrocarbon deposits beneath the surface, like oil. The digestion of ferrite substrata by these archaea yields oil as one the processes by which this valuable resource is sourced. The potential ramifications are enormous.
Hydrocarbons are found throughout the solar system which are not produced by organisms. We should expect to find them on mars as well. We should expect to discover that at least some of the hydrocarbons found here on earth are abiogenic in origin.
Osiris1
5 / 5 (1) Dec 17, 2014
You future Mars explorers, take your bio hazard gear. The life you safe may be your OWN!! Listening to skeptics on the possibilities of native Martian life, however it got there can put you at risk, so protect yourself. Better to be safe than sorry.
Z99
1 / 5 (2) Dec 17, 2014
Phys.org as usual relies on laymen's confusion about what "organic chemical" means. Carbon is the 4th most abundant element in the Universe. (after H, He, and O) It would be astounding if methane (composed of C and H; CH4) was not present on Mars. We've known for decades that the Gas Giants have megatons of 'organic chemicals', and yet why don't we hear chatter about whether we've discovered 'traces of life' there? Simple: this spin is about funding, not science. In fact the abstract cited says that the average methane detected is LESS than what we expected due simply to the reactions of meteoric debris on its surface. This drum-beat for Mars missions is similar to the Shuttle program. A lot of pseudo-science and misdirection, little science, and that only used selectively.
Z99
1 / 5 (2) Dec 17, 2014
What I'd like to know is how deep would life have to be buried for it to be present under, say 1% or 0.01% of the surface? That is: we expect that life will emit telltale organics into the atmosphere (waste products). How deep and how geographically limited would we expect these active areas to be in order to be consistent with the (virtually zero) concentrations we're finding? Obviously, this question would rely on deserts on Earth for a baseline. My cynical guess is that we're not hearing answers to this type of question because it would threaten funding for future studies. IOW its not in the financial interest of either the space agencies or the space scientists to tell us.
TheGhostofOtto1923
1 / 5 (2) Dec 17, 2014
What I'd like to know is how deep would life have to be buried for it to be present under, say 1% or 0.01% of the surface? That is: we expect that life will emit telltale organics into the atmosphere (waste products). How deep and how geographically limited would we expect these active areas to be in order to be consistent with the (virtually zero) concentrations we're finding? Obviously, this question would rely on deserts on Earth for a baseline. My cynical guess is that we're not hearing answers to this type of question because it would threaten funding for future studies. IOW its not in the financial interest of either the space agencies or the space scientists to tell us.
That sounds like something basic and elementary that would have occurred to scientists, don't you think? Why don't you look around on the INTERNET and see what you can find?
Professor Plum
3 / 5 (2) Dec 17, 2014
Me: TopCat22 did you fart?

Shootist: You have art?

sselig: I love playing darts.
baudrunner
not rated yet Dec 17, 2014
@TheGhostofOtto1923 On the one hand, we had Carl Sagan describe Saturn's moon Titan as having the conditions of a pre-biotic Earth. On the other, we know now that over 90% of the methane found here was/is produced by archaea. Regardless of how the methane got in Mars, it is tempting to think that someday we might be prospecting for oil there.
foolspoo
5 / 5 (6) Dec 17, 2014
Baud, if/when we corral interplanetary mining, i will be supremely disappointed if any form of petroleum is the goal. it will be indicative of failure.
Whydening Gyre
5 / 5 (1) Dec 17, 2014
What if....
human exploration craft in the 70's accidentally brought organics to Mars and contaminated the planet...
And now we are seeing the result of that....
TheGhostofOtto1923
1 / 5 (2) Dec 17, 2014
On the other, we know now that over 90% of the methane found here was/is produced by archaea
THAT is what is known as a theory. Similar such theories said that mars and the moon were dry.

We find abiogenic hydrocarbons all over. What do you suppose happened to earths share? Maybe the archaea ate it.
movementiseternal
Dec 18, 2014
This comment has been removed by a moderator.
Z99
5 / 5 (2) Dec 18, 2014
Incidentially, they found chlorobenzene and dichloro- -ethane, -propane and -butane, thought to be the thermal decomposition of other organics with the pervasive perchlorite (bleach) present in the soils.
Arguing that methane is a 'building block' of life is like arguing hydrogen is. Both are so common in the Universe their presence is not evidence of much of anything. As I said previously, the methane is lower than expected based on the models of (meteoric) dust present on the surface. I wonder if this dust is the source of the chlororganics, too?
SoylentGrin
5 / 5 (1) Dec 18, 2014
What if....
human exploration craft in the 70's accidentally brought organics to Mars and contaminated the planet...
And now we are seeing the result of that....

If a trace amount of Terrestrial microbes could inoculate an entire planet in 40 years, it would mean that Mars was extraordinarily fertile. Which would mean that it would probably have its own life already.
Torbjorn_Larsson_OM
4 / 5 (4) Dec 19, 2014
I see elsewhere from a good source (John Timmer @ Ars) that impact generated methane has been ruled out for the atmosphere findings. [And then is less likely for the ~ 4 billion year old Cumberland organics, if those are derived from rock inclusions.] But I haven't had time to read the papers.

CH4 for methanophiles is, together with CO2 and the hydrogen rich waters found in crusts for acetogenes, the root metabolisms on Earth and in the most likely life emergence pathway (alkaline hydrothermal "engine" pathway). Possibly from there methanogenes can evolve but it is the hardest step and demands efficient metallo-protein enzymes.
Torbjorn_Larsson_OM
3.5 / 5 (4) Dec 19, 2014
@foolspoo: The find tells us Mars is biologically and/or geologically active. (Probably both.)

@qitana: I don't know about this instrument, but usually they have test samples when they check out function. (E.g. that is how some of Rosetta's instrument did it for gases.)
Torbjorn_Larsson_OM
4 / 5 (4) Dec 19, 2014
@Z99: The baseline is what would be expected from impactors. The seen spikes (and their similar earlier remote observations) apparently are too massive. Specifically, they could exclude a nearby impactor for these spikes.

The depth where organics survive radiation over 100's of thousands of years, and so can be a food source, have been reported long since out of Curiosity. IIRC that zone starts a few m down. (0.5 m of rock protects organics for 0.5 million years, but Mars is geologically sluggish.) Of course you would expect life to be around the ground ice and perhaps water, so likely 100-600 m down.

Re methane, see my earlier comment: It, and CO2/H4 for more organic fixation and energy release in the presence of electron acceptors such as volcanic derived NO2, is the root metabolism here and presumably elsewhere. That, together with finding organics at all, is prerequisites for habitability as we know it.
foolspoo
5 / 5 (2) Dec 19, 2014
That is a ginormous presumption Torbjorn. I hope this is what we eventually discover, but these findings could have been initiated by a relatively recent impact event. im sure there are many possibilities, possibilities that i'm ignorant to, that can not be ruled out just yet.
katesisco
1 / 5 (2) Dec 21, 2014
z99 and tbjorn ask good questions. My theory is our sun is a dying magnetar and cyclically emits from the equator stronger and perhaps unidentified energy that heats the core of planets. This heating provokes the release now identified on Mars, what little remains to be released. Perhaps this energy release is reinforced by planetary alignments. Perhaps we will fall under Jupiter's influence as Sol's wanes.
I suspect Earth endured enormous energy washes from Sol and 600,000,000 y a weakened sufficiently to allow life to begin and endure periodic setbacks. Remember comb jellies began BEFORE sponges.
baudrunner
not rated yet Dec 21, 2014
We find abiogenic hydrocarbons all over. What do you suppose happened to earths share? Maybe the archaea ate it.
Well, now. That's what we call being facetious. You're just being argumentative, not at all a desirable personality trait.

Methanogens digest the iron in the crust and turns it into its waste products, an ongoing process which technically makes the hydrocarbon source replenishable, but we are just using it up too fast. The theory" if you will, is that this same process is going on inside Mars, and why do you dispute this?

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