Evidence from Curiosity Rover Shows Mars Once Had Oxygen-Rich Atmosphere

[Ichingcarpenter]

Mars’ atmosphere is thin and cold, composed primarily of carbon dioxide along with other trace gases and some water vapor. Evidence has continued to mount, however, that the rarified atmosphere we see today once used to be much thicker and possibly warmer, making it potentially more life-friendly early on. Just how thick and how warm is still a subject of much debate, but there is also another interesting aspect to all of this: New evidence from the Curiosity rover has shown that the Martian atmosphere also used to have a lot more oxygen in it than it does now. Today, only very small traces of oxygen can be found, as opposed to Earth’s oxygen-rich atmosphere. So what does this mean? Could there be biological implications?


It had already been assumed that there must have once been more oxygen (O2) than there is now, to account for all of the reddish iron oxide (rust) on the surface, which would require both water and oxygen. Other studies have also supported this hypothesis, and suggested that there used to be more oxygen, but now the new data from Curiosity indicates that there was probably even more oxygen than first thought. That clue comes from the high levels of manganese oxide found in some rocks by the rover. It is the most direct evidence found so far for a previous oxygen-rich atmosphere earlier in Mars’ history.

On Earth, most of the oxygen comes from living organisms such as cyanobacteria, but whether that was ever true for Mars is still unknown. Image Credit: Wikipedia/Doc. RNDr. Josef Reischig, CSc.
On Earth, most of the oxygen comes from living organisms such as cyanobacteria, but whether that was ever true for Mars is still unknown. Image Credit: Wikipedia/Doc. RNDr. Josef Reischig, CSc.
“We found 3 percent of rocks have high manganese oxide content,” said Agnès Cousin of the Research Institute in Astrophysics and Planetology in Toulouse, France, at the European Geophysical Union meeting in Vienna, Austria, last week, and reported in New Scientist. “That requires abundant water and strongly oxidising conditions, so the atmosphere may have contained much more oxygen than we thought.”

Almost all of that oxygen escaped to space as the atmosphere thinned over the next few billion years. Now there are only tiny trace amounts left.

It’s also interesting to note that many of the manganese oxide deposits are close to where there used to once exist a lake inside Gale crater, where the rover has been exploring since 2012. That flowing water with dissolved oxygen in it may have helped to create the deposits. It is not yet known exactly how old the deposits are, but additional data from Curiosity should help to determine that.


http://www.americaspace.com/?p=93145

[tblue37]

1. k&r. nt

[longship]

2. Great info! R&K nt

[localroger]

3. That pretty much means there was abundant life, full stop

They're playing it close to the vest but oxygen loves to combine with other elements so the only way to keep large amounts of it floating free is for something to keep prying the oxygen away from those other elements, which takes energy. On Earth that is done by plants using the energy from sunlight to split CO2, and there are no known mineral mechanisms for doing that on any but a trace scale.

This is one of the things they are trying to detect about exoplanets; sometimes during a transit they can get spectral lines that might reveal what's in the planet's atmosphere. If they ever get one showing positive for free oxygen that will be a strong sign of abundant life now.

[cstanleytech]

6. Having more oxygen and even oxygen with some water doesnt automatically = there had to be life.

Could it have had it? Yes but so far they havent discovered anything that proves it actually once had life on it.

[localroger]

8. Actually, pretty much, yes it does

Maintaining free oxygen in large quantities basically requires that a lot of energy be expended continually separating oxygen from the things it likes to attach to. The reason they are excited about the manganese depsosits is that they suggest a high concentration of oxygen for a long time, and pretty much the only way you get that is with plant life to keep replenishing the oxygen. It's after the plant life goes extinct that everything turns red when the oxygen combines with the iron in the soil.

[cstanleytech]

10. The article itself lists other possible reasons.

"Of course, the presence of oxygen brings up other questions, relating to possible biological implications. On Earth, by far most of the oxygen is produced by living organisms, via photosynthesis, but what about Mars? Could this be evidence for life early in Mars’ history? Perhaps, although there are other possibilities. Oxygen can also be produced by ultraviolet radiation from the Sun breaking down carbon dioxide, the electrolysis of water, or the photolysis of ozone. Typically, those sources produce much smaller amounts of oxygen. Earth’s atmosphere is rich in oxygen because organisms keep replenishing it, and the gas remains stable. Whether Mars’ atmosphere once being rich in oxygen also points to a biological origin is simply unknown at this point, but it’s possible. Also, while oxygen is produced by some organisms, it can be deadly for others."

If you want to argue in favor of your theory with Paul Scott Anderson then by all means go for it.

[WhiteTara]

4. I wonder if that is what will be found with Earth millenia from now. nt

[NickB79]

5. Free oxygen is a detriment to the evolution of early life, though

A planet with large amounts of naturally occurring free oxygen would have it's primordial stew of organic compounds quickly oxidized before life could arise. All those long chains of organic molecules would be no more in an environment with highly reactive oxygen present.

Timing here is crucial. If Mars developed substantial amounts of free oxygen after life first evolved, that's a good thing. If it had free oxygen from the time of creation, that's a bad thing.

[drm604]

7. The thinking is that it very possibly was life that created the large amounts of atmospheric O2.

Other processes generally create much smaller amounts of O2.

Life on Earth started as anaerobic bacteria (bacteria that do not need oxygen). Some of these eventually evolved into forms that created O2 as waste. This eventually transformed the Earth's atmosphere and lead to the evolution of oxygen breathing life.

So if there was life on Mars, it very likely arose before there was large amounts of atmospheric O2.

[localroger]

9. There is no natural non-life process that can maintain a high concentration of O2

...at least that we know of, but any such process would also require a lot of energy input. Plant life gets that from sunlight.

[cstanleytech]

11. "There is no natural non-life process that can maintain a high concentration of O2"

http://www.popularmechanics.com/space/deep-space/a20213/newly-discovered-star-has-an-almost-pure-oxygen-atmosphere/

[localroger]

12. Well, okay, on a collapsed star via nuclear processes

That's not what we're talking about on Mars though. Mars isn't a collapsed star, it's an ordinary planet like Earth without hundreds of thousands of gees of gravity to drive weird nuclear reactions.

[cstanleytech]

13. No, its currently a planet that has some anomalies that "might" have or had

life on it in the distant past but which has not been confirmed with scientific evidence.

Edit: And BTW so far that star is unique for the amount of oxygen but it doesnt mean life is present on it though its cool to read about.

[localroger]

15. Life is not responsible for the oxygen on the star.

Life cannot do that in that environment. On the other hand, life is almost certainly responsible for the oxygen that existed in mars' ancient atmosphere, because in all our experience that is a thing life does and only life can do.

[cstanleytech]

16. Hey if you want to hold to that theory as being the only explanation feel free but I prefer

to wait and see what the science says.

[localroger]

17. You'll be waiting a long time

There are very persuasive theories that life in the Solar System actually originated on Mars, because it was smaller and further from the Sun and cooled faster, and that life was carried to the young Earth by meteorite ejecta. No proof of that of course but it carries some weight, since it does seem like life appeared here about instantaneously as soon as the crust was solid.

And really, you should look into the chemistry of what it takes to keep free oxygen in the astmosphere long enough to produce the kind of minerals they are finding on Mars. This is both a sustained and energy-intensive thing we are talking about. Life is actually the simple Occam's Razor solution to the problem. If it wasn't life, you are proposing some radically weird chemistry which, if it was that pervasive, our rovers would probably have found some evidence for.

No, it's not a certainty. But it's as close to certain as things ever get in real life. Mars had life. Maybe not complex life; all it would take is some lakes lined with cyanobacteria. But that is by far the most likely explanation for these new mineral deposits, and it does have far reaching ramifications.

[Odin2005]

14. This seems obvious to me simply from the fact that Mars is red.

Earth did not had red rocks before the Great Oxygenation Event, they need oxygen to form because the red color is from iron oxide.

[Judi Lynn]

18. Massive volcanic eruptions rocked Mars billions of years ago - and could have melted its thick ice s

Massive volcanic eruptions rocked Mars billions of years ago - and could have melted its thick ice sheet to make the planet habitable

Data came from Mars Reconnaissance Orbiter's mineral-mapping sensor

It focused on a textured region of southern Mars called 'Sisyphi Montes'

Minerals created from such subglacial volcanism on Earth found in area

It could help reveal if Mars had flowing water and was once habitable

By Ellie Zolfagharifard and Abigail Beall For Dailymail.com

Published: 15:50 EST, 3 May 2016 | Updated: 16:58 EST, 3 May 2016
Nasa has found evidence that a massive ice sheet once covered Mars.

New data from the Mars Reconnaissance Orbiter points to possible ancient volcanoes that erupted beneath ice far from where Nasa thought all the ice was located.

As well as proving its icy past, the study could help reveal if the Martian environment had flowing water and was once habitable, researchers claim.

Sheridan Ackiss of Purdue University, Indiana, used the Mars Reconnaissance Orbiter's mineral-mapping sensor to investigate surface composition.

His team focused on a strangely textured region of southern Mars called 'Sisyphi Montes', which is studded with flat-topped mountains.

More:
http://www.dailymail.co.uk/sciencetech/article-3571922/Was-red-planet-icy-world-Evidence-sub-glacial-volcanoes-provide-evidence-water-Mars.html#ixzz47dIcB4HT