Skip to main content

Scientists discover evidence of ancient, nitrogen-rich Martian groundwater hiding in Antarctica

Pieces of Mars made their way across the solar system to Antarctica, where they were discovered in the 1980s.
Pieces of Mars made their way across the solar system to Antarctica, where they were discovered in the 1980s.
(Image: © Shutterstock)

A bit of 4-billion-year-old rock blasted off the Martian surface about 15 million years ago and eventually landed in Antarctica, where explorers found it in 1984. In the decades since, organic compounds found in that meteorite have been sources of controversy: Did they come from Mars, or did the meteorites get contaminated on Earth? Now, a team of Japanese researchers has reexamined the meteorites, and say they found traces of ancient oceans, rich in useful carbon and nitrogen — key ingredients for life.

The meteorite, known as Allan Hills 84001, after the location where it was first discovered, has long been known to contain organic materials. The hunk of space rock has been the subject of paper after paper after paper debating whether those materials came from Earth or Mars. There's even been a controversial claim, as Live Science sister site Space.com reported in 2016, that evidence for actual Martian life is hiding out in the rock.

The trouble was that researchers could never rule out the possibility that organic molecules from Antarctica got mixed up with the meteorites during their centuries locked in ice. Alternatively, the meteorite could have been contaminated with organic matter in a laboratory. 

Related: 50 amazing facts about Antarctica

But now the researchers have taken extraordinary pains to rule out those possibilities. Their results suggest the organic compounds come from Mars — and for the first time show the meteor also contains nitrogen-bearing organic materials. Most nitrogen we've discovered  on Mars is locked up in inert nitrogen gas (N2) or in harsh chemicals in the soil that break down organic matter, the researchers wrote. These newly-discovered organic nitrogen compounds in the carbonate suggest that if life did exist on Mars, it would have had access to the same forms of nitrogen that Earthly life relies on.

Together, the researchers wrote in the paper, which was published April 24 in the journal Nature Communications, these findings amount to the signature of an groundwater environment with plenty of potentially life-giving organic material.

The researchers studied the meteorites in a "class-100 clean lab," an environment where everyone wears head-to-toe bodysuits and the airflow is controlled to keep particulates from floating around. (Typically, such labs are used when manufacturing delicate advanced technologies like spacecraft or certain pharmaceuticals.) Past research into Allan Hills 84001, such as a 1999 study in the journal Advances in Space Research that argued the organics likely came from Mars, took place in more typical laboratory environments.

In their ultraclean environment, the scientists peeled off tiny grains of carbonate — the compound in the 4-billion-year-old meteorites. Then, they blasted the surfaces of the grains with a beam of focused charged molecules, or ions, to remove surface contaminants. The material underneath that surface layer, the researchers argued, represents a close approximation of the chemicals inside the meteorites before they were exposed to Earth.

They found levels of organic nitrogen far higher than could easily be explained by contamination from Antarctic ice, suggesting the nitrogen-bearing organic material entered the rock as it formed. The carbonate in Allan Hills 84001 formed in water, researchers believe. On Earth, carbonates like limestone and calcite are also the dried-out remnants of old water sources. Taken together, these lines of evidence suggest that the organic nitrogen compounds were plentiful in early Martian oceans.

That's important because "nitrogen is an essential element for all life on Earth, as it is necessary for protein, DNA, RNA and other vital materials," the researchers wrote.

These results fit with other evidence from the Red Planet. NASA's Curiosity rover and Viking landers found traces of organic material on the Martian surface. But rover instruments can't do the battery of tests that an Earthbound laboratory can,, so the rover data doesn't tell scientists where the organic compounds came from, how old they are or how they formed. This research, if borne out, suggests that at one point, when Mars was covered in oceans, those oceans flowed with organic matter.

All of that said, organic materials form in many lifeless places in the solar system, most notably comets. There's even evidence for organic material in the dust floating between stars, Space.com reported in 2011. So whether these apparent ancient, organic-rich oceans on Mars ever hosted life is still a mystery.

Originally published on Live Science.

OFFER: Save 45% on 'How It Works' 'All About Space' and 'All About History'!

For a limited time, you can take out a digital subscription to any of our best-selling science magazines for just $2.38 per month, or 45% off the standard price for the first three months.View Deal

  • Broadlands
    Three points. (1) "On Earth, carbonates like limestone and calcite are also the dried-out remnants of old water sources." On Earth the sedimentary carbonate limestones are all biologically formed, not just dried out water. (2) " This research, if borne out, suggests that at one point, when Mars was covered in oceans, those oceans flowed with organic matter". If true, where did the organic matter go? To date, there have been no findings of any organic cellular remains by any of the rovers. (3) How did life on Mars get started in the presence of unattenuated intense UV radiation from the Sun? No photosynthesis?
    Reply
  • TorbjornLarsson
    This is interesting! Not least because ALH84001 was buried close to the subsurface for a very long time and so points to early organics survival that Perseverance may find. The nitrogen chemistry points to a more pH neutral environment at the time, which is also promising.
    Reply
  • TorbjornLarsson
    Broadlands said:
    Three points. (1) "On Earth, carbonates like limestone and calcite are also the dried-out remnants of old water sources." On Earth the sedimentary carbonate limestones are all biologically formed, not just dried out water. (2) " This research, if borne out, suggests that at one point, when Mars was covered in oceans, those oceans flowed with organic matter". If true, where did the organic matter go? To date, there have been no findings of any organic cellular remains by any of the rovers. (3) How did life on Mars get started in the presence of unattenuated intense UV radiation from the Sun? No photosynthesis?

    Q&A: (1) So? They don't want to draw unsupported conclusions, since calcite carbonates can be deposited from inorganic locales such as hot springs, volcanoes or in the mantle (say, in kimberlites) https://en.wikipedia.org/wiki/Calcite ].

    (2) The study of life conditions and possible life is a current study of Mars landers. They have found organic matter, consistent with this martian meteorite find. The 2020 rover is the first mission that will enable sample return, which is a prerequisite for current technologies to identify life - you need a large observatory and study from macro- to microscales to identify e.g. microbialities (sedimentary bacterial remains).

    (3) Any early life likely evolved in the same way that phylogenies say it evolved early here on Earth, originating in oceanic alkaline hydrothermal vents, far beneath the upper meter of water where UV penetration can be harmful https://www.nature.com/articles/nmicrobiol2016116 ]. We know early Mars had a large ocean akin to Earth's early global ocean https://news.berkeley.edu/2018/03/19/mars-oceans-formed-early-possibly-aided-by-massive-volcanic-eruptions/ ], and we know it had alkaline hydrothermal vents (Spirit got stuck and died in silica deposits of a fossil such vent). The last universal common ancestor was still not photosynthetic , that evolved later as life spread across the ocean floor towards the surface (which in the case of Earth happened latest at 3.2 billion years, where at least 3 % of the surface was land crust; https://www.theguardian.com/science/2020/mar/02/earth-may-have-been-a-water-world-3bn-years-ago-scientists-find ). Photosynthesis is a derived metabolism, ancestral Earth life was chemoautotroph (Wood-Ljungdahl pathway, combining CO2 and H2 for organics and energy).
    Reply
  • Broadlands
    Early organics survival? That implies the presence of early life. How could life (DNA/RNA) have evolved given the extreme conditions that would have existed without some UV protection from the young Sun? Those same conditions exist today on Mars. Photosynthesis requires both the visible spectrum and UV protection. Yes, it is derived, but from a last common ancestor that was both a hyperthermophile and a minimal oxygen requiring microaerophile...e.g. Aquifex.... the Aquificae. Hydrothermal vents? Very problematic with respect to the evolution of peptide and nucleotide bond formation. Both require the input of energy snd the removal of water. ..an evaporative drying out, facing the Sun's UV. Repeated wetting and drying needed for primitive chain extension and growth.

    Given the negative results of the rovers to find any evidence of organic cellular remains, the possibility of life on Mars, going back billions of years ago is remote. There are not even any gray or black shales that would be expected had organic matter been present, survived and accumulated. Nothing but sandstone and silts devoid of biological carbon. Hematite? A dried out iron oxide formed from precursor ferric oxyhydroxides that have lost their water.
    Reply
  • Hayseed
    What are the rules when playing with probability? We use probability for quantum mechanics and cosmic creation measurements. There is a consensus of this science.

    But the environment and time needed to probably evolve a protein is non-existent.

    But we still insist on life as evolving. And try to prove it. Probability Numbers be damned.

    If probability did not evolve life, what did?

    Alien visitors? Was life seeded? They had a huge catalog of seeds.

    Obviously a certain environment is needed, or other life would be detected. The alien visitors must have a lot of propulsion, time and patience to find such spots.

    How else could one possibly explain life?
    Reply
  • Broadlands
    It should be unnecessary to point out that using a 'catalog of seeds' as an argument only moves the problem and its location to some other planet.
    Reply
  • TorbjornLarsson
    Broadlands said:

    Early organics survival? That implies the presence of early life. How could life (DNA/RNA) have evolved given the extreme conditions that would have existed without some UV protection from the young Sun? Those same conditions exist today on Mars. Photosynthesis requires both the visible spectrum and UV protection. Yes, it is derived, but from a last common ancestor that was both a hyperthermophile and a minimal oxygen requiring microaerophile...e.g. Aquifex.... the Aquificae. Hydrothermal vents? Very problematic with respect to the evolution of peptide and nucleotide bond formation. Both require the input of energy snd the removal of water. ..an evaporative drying out, facing the Sun's UV. Repeated wetting and drying needed for primitive chain extension and growth.



    Given the negative results of the rovers to find any evidence of organic cellular remains, the possibility of life on Mars, going back billions of years ago is remote. There are not even any gray or black shales that would be expected had organic matter been present, survived and accumulated. Nothing but sandstone and silts devoid of biological carbon. Hematite? A dried out iron oxide formed from precursor ferric oxyhydroxides that have lost their water.

    This is a Gish gallop - so I have to ask if this will be a long gallop thread if you are a creationist, or are you interested in the science despite letting your personal incredulity affect your reading?

    Meanwhile, and I have already said that, scientists are curious, excited and in high activity regarding the possibility of extant or extinct life on Mars. And organics means carbon compounds more complex than CO2 where biomolecules are a major but not ell encompassing category https://en.wikipedia.org/wiki/Organic_chemistry#Biomolecules ]. Many organic compounds are produced in astronomical or geological environments, and distinguishing between, say, volcanic or meteorite produced organics is an ongoing concern for martian (and other) astrobiology.

    I have already noted that photosynthesis does not come into early evolution. Alkaline hydrothermal vents on the other hand seems to have been where the universal ancestral lineage evolved. So there are consistent evidence from trees and other biology: not photosynthesis, but ocean chemotrophy.

    There is also no principle problem in vent evolution, which is ongoing with modern life. On the contrary experiments show sugars, nucleobases and nucleotides are formed and polymerized in rapid heat/cold cycling. PCR is after all how we amplify sequences! The most productive environment for spontaneous assembly of membrane vesicles out of different length lipids is the typically 70 degC salty alkaline hydrothermal vent environment, and so on. The missing compound type is amino acids, but they were produced all over in the else acidic environment and especially nearby acidic hydrothermal vents in plate tectonic oceanic ridge systems (where oceanic plates form from upwelling mantle material). It is an odd claim to say that condensation reactions happen here or there, but in cells as well as under water they occur in gels. Mind that the small group of biochemists that push for wet/dry cycling fresh water pool chemistry are neither motivated by biology or geology (doubtful much, if any, land existed on early Earth), or has a current broad acceptance as promising explanation for early evolution.
    Reply
  • TorbjornLarsson
    Hayseed said:
    What are the rules when playing with probability?

    That life evolves to 100 % - all life evolves - and that is obviously how biologists "explain" (observe) life. That is both an old observation and - better - a well tested theory so we know the process intimately. In fact, it is the best tested theory in all of science (due to the combinatorial nature of phylogenetic trees - that all life is related is 10^2000+ times more likely than that there were several early evolving lineages).

    To quote Broadlands, it should be unnecessary to point out that proteins evolve very fast - your immune system depends on antibody protein evolution (but with a non-germ cell genetic memory in the form of somatic B and T cell lineages). Typically such proteins adapt to result in a robust antibody producing cell population defense within days. The non-biological idea of serial-"lucky-monsters"-in-individuals instead of massive parallel-and-selective-in-populations changes as in evolution is neither here nor there - in fact, I believe it is derived from superstition anti-science 'arguments'. The site is called LiveScience, so I suggest we stick with the science.
    Reply
  • Broadlands
    TorbjornLarsson said:
    This is a Gish gallop - so I have to ask if this will be a long gallop thread if you are a creationist, or are you interested in the science despite letting your personal incredulity affect your reading?

    Meanwhile, and I have already said that, scientists are curious, excited and in high activity regarding the possibility of extant or extinct life on Mars. And organics means carbon compounds more complex than CO2 where biomolecules are a major but not ell encompassing category https://en.wikipedia.org/wiki/Organic_chemistry#Biomolecules ]. Many organic compounds are produced in astronomical or geological environments, and distinguishing between, say, volcanic or meteorite produced organics is an ongoing concern for martian (and other) astrobiology.

    I have already noted that photosynthesis does not come into early evolution. Alkaline hydrothermal vents on the other hand seems to have been where the universal ancestral lineage evolved. So there are consistent evidence from trees and other biology: not photosynthesis, but ocean chemotrophy.

    There is also no principle problem in vent evolution, which is ongoing with modern life. On the contrary experiments show sugars nucleobases and nucleotides are formed and polymerized in rapid heat/cold cycling. PCR is after all how we amplify sequences! The missing compound type is amino acids, but they were produced all over in the else acidic environment and especially nearby acidic hydrothermal vents in plate tectonic oceanic ridge systems (where oceanic plates form from upwelling mantle material). It is an odd claim to say that condensation reactions happen here or there, but in cells as well as under water they occur in gels. Mind that the small group of biochemists that push for wet/dry fresh water pool chemistry are neither motivated by biology or geology, or has a current broad acceptance as promising explanation for early evolution.

    Ignoring your uncalled for personal attack, broad acceptance, conventional wisdom, or consensus are not 'promising explanations' or criteria used by scientists. Much of what you say is true but conflicts with the actual, evidence obtained from the several rovers. If any organic cellular remains are to be found in billion year-old sediments beyond trace amounts they would not confirm that life was ever present there because they could have entered as carbonaceous chondrites. A problem you recognize? For life on Mars to have ever evolved it would have to have run the gauntlet from the intense solar UV underwater to life at the surface throughout Martian history. Ad hoc refuges and sanctuaries such as caves or under sediments don't count for much. As for hydrothermal vents producing polynucleotides and oligonucleotides leading to DNA and primitive proteins, the problems remain... Richard E. Dickerson, 1978: "The central problem in understanding how the polymers were formed on the primitive earth is understanding how reactions requiring both the input of energy and the removal of water could take place in the ocean." The same applies to Mars or anywhere else that life is said might be located
    Reply