Ancient rocks show life could have flourished on Earth 3.2 billion years ago

Feb 19, 2015

Photo: R. Buick / UW

By Hannah Hickey

A spark from a lightning bolt, interstellar dust, or a subsea volcano could have triggered the very first life on Earth.

But what happened next? Life can exist without oxygen, but without plentiful nitrogen to build genes – essential to viruses, bacteria and all other organisms – life on the early Earth would have been scarce.

The ability to use atmospheric nitrogen to support more widespread life was thought to have appeared roughly 2 billion years ago. Now research from the University of Washington looking at some of the planet’s oldest rocks finds evidence that 3.2 billion years ago, life was already pulling nitrogen out of the air and converting it into a form that could support larger communities.

“People always had the idea that the really ancient biosphere was just tenuously clinging on to this inhospitable planet, and it wasn’t until the emergence of nitrogen fixation that suddenly the biosphere become large and robust and diverse,” said co-author Roger Buick, a UW professor of Earth and space sciences. “Our work shows that there was no nitrogen crisis on the early Earth, and therefore it could have supported a fairly large and diverse biosphere.”

The results were published Feb. 16 in Nature.


Read the full article by clicking the name of the source located below.

19 comments on “Ancient rocks show life could have flourished on Earth 3.2 billion years ago

  • Now research from the University of Washington looking at some of the planet’s oldest rocks finds evidence that 3.2 billion years ago, life was already pulling nitrogen out of the air and converting it into a form that could support larger communities.

    Nitrogen is very common in the Solar System.

    http://voyager.jpl.nasa.gov/science/neptune_triton.html

    The question about the early Solar System, is when the Earth or proto-planets’ acquired abilities to retain an atmosphere or volatile molecules, due to temperatures and the Solar Wind actively removing volatiles.



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  • This is “…hard evidence…” of two incontrovertible facts: that life on this planet began a billion years earlier than previously thought; and that scientific methodologies work.

    Which seems pretty good to me.



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  • The earlier life appeared on earth, either the easier it is to spontaneously generate, or the easier it is to be imported from other planets. In either case, that increases the probability that life is rampant throughout the universe.



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  • Stafford Gordon Feb 20, 2015 at 12:08 pm

    This is “…hard evidence…” of two incontrovertible facts: that life on this planet began a billion years earlier than previously thought; and that scientific methodologies work.

    I’m not sure that can be claimed.
    The OP mentions nitrogen fixation, but there are certainly prior claims that life started earlier than this!

    http://en.wikipedia.org/wiki/Timeline_of_evolutionary_history_of_life
    for the last 3.6 billion years, simple cells (prokaryotes);
    for the last 3.4 billion years, cyanobacteria performing photosynthesis;
    for the last 2 billion years, complex cells (eukaryotes);
    for the last 1.2 billion years, eukaryotes which sexually reproduce
    for the last 1 billion years, multicellular life;

    @OP- The ability to use atmospheric nitrogen to support more widespread life was thought to have appeared roughly 2 billion years ago. Now research from the University of Washington looking at some of the planet’s oldest rocks finds evidence that 3.2 billion years ago, life was already pulling nitrogen out of the air and converting it into a form that could support larger communities.



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  • Being all too human we go gaga when we hear the number one billion. A thousand million. Boy, that must be a lot! Try to get your head around the jaw-dropping concept of a billion years. Wow! That’s a really, really long time. Winding the universe, the space-time continuum back to the Big Bang we calculate its origin to have occurred about 13.8 billion years ago.

    But try a thought experiment. If science had measured the universe at “only” one trillion years old, it would be about 73 times older than our current figure of 13.8 billion. Within a comprehensive time scale model, imagine the universe in proportion to the 20th century = 100 years between 1900 and 2000. The Earth (and solar system) is about 4.55 billion years old or 4.55 / 13.8 = .33 or 33% of the total time elapsed since the Big Bang. On the 20th century model the Earth would have emerged around 1967. Vertebrate fish with hinged jaws evolved between 400 million to 500 million years ago or 450,000,000 / 13,800,000,000 = .03 or 3% of the elapsed time since the Big Bang; evolving around 1997.

    Because the universe -the space time continuum of matter and energy- is ALL THAT THERE IS, we tend to confuse the empirical fact of its age with infinity. Archbishop Ussher aside, many philosophers believed the universe had existed in a steady state for eternity. The universe is finite in age – no different from a 5-year-old boy or a 100-year-old man. 13.8 billion seems like “infinity” but it is nothing more than a small integer. Look at the shark on your restaurant dinner plate. Its ancestors have been swimming around in mundane seas for 3% of all time. The history of the universe is compressed into a much shorter time frame than we are conditioned to reference



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  • Wow. Really.

    Also, in my naivety, I’m beginning to think that the really surprising aspect of life on this planet is not its existence at all (not only we seem to discover one new way life’s building bricks could have occurred naturally every week, it also seems that life began and became pervasive on an ASAP basis), but the fact that all the life there is on this planet seems to belong to the same strain.
    I’m beginning to expect this latter fact to pose substantial constraints on the likelihood of having life rather than the presence of life’s basic materials…

    But all of that might just be because I’m just a hobbyist, as far as biology is concerned.



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  • A good read for those interested in getting to grips with the phrase “a long time” in relation to the universe is “The Five Ages of the Universe: Inside the Physics of Eternity” by Fred Adams. The book is presented as a history of the universe from the time of the big bang up to 10^100 years. That might not seem like a big number to non-mathematical types but consider that the current age of the universe is 10^13 years. If you add one to the index, 10^14, you’ve multiplied the previous number by 10. The entire time the universe has existed up until now, multiplied by 10. And that’s only 10^14. Mind-blowingly large doesn’t begin to cover it.



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  • As a layman who only knows what he reads from Wikipedia -and from other more “respectable” sources, the research findings discussed in the article make sensationalist and misleading claims: Ancient rocks show life could have flourished on Earth 3.2 billion years ago. Professor Roger Buick himself may be flirting with unethical self-aggrandizement in exaggerating the significance of his inconclusive and heavily speculative findings.

    Here are the meat and potatoes of the foundational science from Wikipedia:

    Biochemistry
    Nitrogenases. The most important role of the molybdenum in living organisms is as a metal heteroatom at the active site in certain enzymes in nitrogen fixation in certain bacteria…In 2008, evidence was reported that a scarcity of molybdenum in the Earth’s early oceans was a limiting factor for nearly two billion years in the further evolution of eukaryotic life (which includes all plants and animals) as eukaryotes cannot fix nitrogen, and must therefore acquire most of their oxidized nitrogen suitable for making organic nitrogen compounds, or the organics themselves (like proteins) from prokaryotic bacteria.

    Scientists laid out the seminal role of evolving enzymes in making “nitrogen fixation” necessary for”further” biological evolution. Scientists never claimed that no life evolved on earth until 2 billion years ago as Buick misleads the press and public to to believe. Scientists qualified a tentative time frame of nearly 2 billion years ago when enzymes (notably molybdenum) necessary for nitrogen fixation were so scarce in oceans that eukaryotic life was limited in its evolution.

    Here from the article is the meat and potatoes of the University of Washington research:

    The evolution of the nitrogen-fixing enzyme nitrogenase, which reduces atmospheric N2 to organic NH4+, thus represented a major breakthrough in the radiation of life, but its timing is uncertain5, 6. Here we present nitrogen isotope ratios with a mean of 0.0 ± 1.2‰ from marine and fluvial sedimentary rocks of prehnite–pumpellyite to greenschist metamorphic grade between 3.2 and 2.75 billion years ago.

    The research basically entailed gathering some very old rocks from South Africa, finding therein evidence consistent with nitrogen-fixing enzyme process necessary for life, dating the rocks to 2.75 to 3.2 billion years ago then proclaiming that life “flourished” a billion years earlier than “Science” thought..

    “Science” thought no such thing but left open a time range beyond 2 billion years dependent on further research Mindful of the complex physical and chemical processes which evolved into biological forms over 2 to 3 billion years ago validates the caveat of the term “time range.” To describe “Life” within such a time range with the term “flourishing” is disingenuous at best; dishonest at worst..

    The authors speculate that pockets of slime one cell thick may have emerged from oceans 3 billion years ago but admitted that no surviving evidence can confirm such phenomena from that time period.



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  • @OP link Here we present nitrogen isotope ratios with a mean of 0.0 ± 1.2‰ from marine and fluvial sedimentary rocks of prehnite–pumpellyite to greenschist metamorphic grade between 3.2 and 2.75 billion years ago. These data cannot readily be explained by abiotic processes and therefore suggest biological nitrogen fixation, most probably using molybdenum-based nitrogenase as opposed to other variants that impart significant negative fractionations7. Our data place a minimum age constraint of 3.2 billion years on the origin of biological nitrogen fixation and suggest that molybdenum was bioavailable in the mid-Archaean ocean long before the Great Oxidation Event.

    What this is actually saying is that there is evidence of biological nitrogen fixation 3.2 billion years ago in some of the oldest existing rocks on Earth which existed in a pre-oxygen atmosphere at that time.
    Prokaryotes and cyanobacteria already existed at this time according to the time-line I linked above.



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  • Alan4 provides indispensable information for fleshing out a critical perspective on the article.

    Here is the foundational science from which the hypothesis is adapted:

    Did molybdenum control evolution on Earth?

    The argument has therefore been made that as a result of the high aquatic concentration of molybdenum, organisms developed the highly efficient molybdenum-containing coenzyme, nitrogenase.. as a means of fixing atmospheric nitrogen. With more rapid synthesis of amino acids, photosynthetic organisms could reproduce at a more rapid rate, significantly boosting oxygen production…It is now accepted widely that molybdenum availability could indeed have been key to increasing the rate of oxygenation of our atmosphere. (http://www.rsc.org/Education/EiC/issues/2011September/molybdenum.asp).

    Alan4: …there is evidence of biological nitrogen fixation 3.2 billion years ago in some of the oldest existing rocks on Earth which existed in a pre-oxygen atmosphere at that time.
    Prokaryotes and cyanobacteria already existed at this time according to the time-line I linked above.

    The article makes claims about the time-line of the evolution, emergence; concentration and distribution of the enzymes that made nitrogen fixation possible on a “life- flourishing” order of magnitude 3 billion years ago.

    The chemical signature of the rocks suggests that nitrogen was being broken by an enzyme based on molybdenum, the most common of the three types of nitrogen-fixing enzymes that exist now…Genetic analysis of nitrogen-fixing enzymes have placed their origin at between 1.5 and 2.2 billion years ago.

    The enzyme origin date range is grossly inaccurate. The GOE (Great Oxygenation Event) ramped up about 2.6 billion years ago. Alan4 has documented that for the last 3.4 billion years, cyanobacteria (has been) performing photosynthesis.…. “Molybdenum found in the enzymes of ancient cyanobacteria could have oxygenated the atmosphere allowing life to evolve.” ( from the article cited: Did molybdenum control evolution on Earth?)

    The 3.2 billion-year-old rocks dated in the research "prove" nothing by themselves. The researchers can only speculate in the language of imaginary hypothesis: The authors hypothesize that this MAY be further evidence that some early life MAY have existed in single-celled layers on land, exhaling small amounts of oxygen that reacted with the rock to release molybdenum to the water. (My capitalization). This is storytelling not science.




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  • Melvin Feb 22, 2015 at 1:15 am

    The enzyme origin date range is grossly inaccurate. The GOE (Great Oxygenation Event) ramped up about 2.6 billion years ago. Alan4 has documented that for the last 3.4 billion years, cyanobacteria (has been) performing photosynthesis.…. “Molybdenum found in the enzymes of ancient cyanobacteria could have oxygenated the atmosphere allowing life to evolve.”

    Cyanobacteria (had been) performing photosynthesis for millions of years before the “Great Oxygenation Event”. Any oxygen they produced was being absorbed by dissolved iron in the oceans (and other substances), laying down the beds of iron ore we mine today.
    It was only when the reactive substances were no longer sufficient to absorb all the oxygen that the atmosphere changed to an oxygen rich one. This caused extinctions of many earlier organisms adapted to an oxygen free atmosphere, and favoured those which adapted to use oxygen to evolve into modern life-forms.



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  • This is all so fascinating. With all this information, I am now beginning to question the word ‘life’. It seems to point to a much longer period of coming and the exact definition being totally blurred. The primordial soup I imagined was an isolated incident that spread but now seems like the ingredients are the entire world and process it went through. This must surelly mean that the process is even more rare in the universe?



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  • 14
    Lorenzo says:

    This must surelly mean that the process is even more rare in the universe?

    If the Earth were very atypical… yeah. But I don’t really have enough information to conclude that the Earth is typical or otherwise.



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  • Alan4 once again provides an incisive description of the Great Oxygenation Event (GOE) whose time-line implications should have been compared to misleading or false assertions in the article: Ancient rocks show life could have flourished on Earth 3.2 billion years ago.

    The researchers certainly made a valuable discovery in dating the rocks to 2.75 to 3.2 billion years ago. They showed that some biological nitrogen fixation took place during the time period facilitated by a molybdenum evolving enzyme. (Molybdenum is a very common mineral). Inexplicably, Roger Buick goes out of his way to say that “scientists” believe, based on genetic analysis, that the enzymes which made nitrogen fixation possible evolved for the most part less than 2 billion years ago (1.5 to 2 billion years ago). The 2011 article cited above contradicts the assertion: the high aquatic concentration of molybdenum, organisms developed the highly efficient molybdenum-containing coenzyme, nitrogenase.. as a means of fixing atmospheric nitrogen. The time-line for the evolution and dispersal of this enzyme had to extend back at least more than 2.6 billion years if the Great Oxygenation Event occurred around 2.5 billion years ago. Moreover, if cyanobacteria has been around for 3.4 billion years, the Arnold Schwarzenegger of photosynthesis and oxygen emissions, then the 3.2 billion-year dating of the rocks do not imply marvelous implications -the “flourishing” of anaerobic life for an extra billion years. Evolution controlled emerging concentrations and dispersal of biological nitrogen-fixation enzymes, anaerobic organisms, and oxygen producing photosynthesis measured in tiny increments on a cosmic time scale of hundreds of millions of years. As cyanobacteria and other photosynthetic organisms came on line over 3 billion years ago, there was no likely “explosion” of (anaerobic) life at the 3.2 billion mark because a University of Washington team dated the chemical signature of nitrogen fixation in some rocks dated to the same period.

    I suspect that ego got the better of the researchers whose speculations wildly inflated an isolated finding into a contrived “Theory of Everything” for which there is no evidence. Once more the title itself shows how the researchers colluding with a sensation-seeking media are playing a shell game with the public: Ancient rocks show life could have flourished on Earth 3.2 billion years ago. Read the article again and note how many times “may” or “may have” precede the telling of a wide-eyed story. Storytelling is not science.



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  • The gist of the Rare Earth hypothesis is not that life is rare, but that complex, multicellular (and intelligent) life is rare: however, the authors believe that simple life is common.
    The Earth-Moon system (i.e. such a large moon relative to the planet’s size, with its slowing of Earth’s rotation, tides etc.) is figured to be (a) atypical, which may be true and (b) necessary (or at the very least extremely helpful) for complex multicellular life to arise, which is a bit of a stretch to be honest. [Slow’s rotation of earth, tames the weather, increases littoral niches because of tides etc.]
    But I think even without such a moon, to coin a phrase, “Life will find a way”.



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  • MadEnglishman Feb 22, 2015 at 5:45 pm

    The gist of the Rare Earth hypothesis is not that life is rare, but that complex, multicellular (and intelligent) life is rare: however, the authors believe that simple life is common.

    I think you have misunderstood this. Simple life is likelier to be more common than complex life, because it takes less time to evolve. But many parts of galaxies are hostile to life, many stars are too erratic or short lived to provide stable temperature ranges, and without a large moon to stabilise the axis, seasonal changes and temperatures are all over the place.

    Some (low metalicity) galaxies and parts of galaxies are devoid of the elements required for life where few or no supernova explosions have taken place to provide these.

    The Earth-Moon system (i.e. such a large moon relative to the planet’s size, with its slowing of Earth’s rotation, tides etc.) is figured to be (a) atypical, which may be true and (b) necessary (or at the very least extremely helpful) for complex multicellular life to arise, which is a bit of a stretch to be honest.

    Without the rare formation of a large Moon (see giant collision hypothesis) long-term axial stability is unlikely.

    The formation of planetary systems is much more complex and varied, than many people imagine.

    https://astroclock2010.wordpress.com/cosmic-timeline-17/



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  • I must confess that my comments on Dr. Buick’s research represent many mistakes and ignorance of the science by a layman who is “skimming” sources on the internet. My apologies. For example after further reading: “Nitrogenase.. which accounts for roughly half of the bioavailable nitrogen supporting extant life,” including any molybdenum based enzyme involved in biological nitrogen fixation apparently evolved between 1.5 and 2.2 billion years ago according to the scientific consensus cited by Dr. Buick. The process was a consequence of the oxygenation of the atmosphere due to photosynthesis creating a “critical mass” during this period.

    I’m backing into the science the wrong way but I enjoy the experience of self-correcting as I glean a morsel here and there of semi-intelligible conclusion from texts that remain largely opaque.

    Dr. Buick’s findings that the biological signature of the 2.75 to 3.2 billion-year-old “clean” rocks his team examined tentatively provide hard evidence that the molybdenum enzyme was alive and well and fixing nitrogen in (anaerobic) biological organisms 3.2 billion years ago -a billion years earlier than calculated- is a fascinating theory. If confirmed and maintained by peer review, I’d be the first to nominate him for a Nobel Prize. Still the claims of “flourishing life” during this time seem to come from hubris and a tendency to oversell that clashes with the scientific method calling for further research and duplication of findings.



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