back to article Boffins believe it was volcanoes, not just life, that made Earth what it is today – oxygen rich

The chemical reaction that produced the outburst of oxygen on Earth was sparked by volcanoes belching carbon dioxide after a major tectonic plate shifted about 2.5 billion years ago, according to the latest research. A new study published in Nature Geoscience on Monday describes a scenario that could explain two ancient …

  1. I3N

    Like the bugs on Mars story better ...

    Yes, sure sounds like a kickstarter effort ...

  2. sbt Silver badge

    So what happened to the formaldehyde?

    Surely it would have been preserved?

    Nit: That reaction is super, but normally the numbers in chemical formulae are subscripts.

    1. Steve K Silver badge

      Re: So what happened to the formaldehyde?

      Re: So what happened to the formaldehyde?

      That might explain all the fossils...…

    2. Grikath

      Re: So what happened to the formaldehyde?

      High up in the atmosphere: Joined the natural cycle there.

      Dissolved in water: Used as food by bacteria, moving that part of the process into the carbon cycle, effectively making the reaction a one-way trip giving a net O2 yield. Which is why it's considered as an alternative mechanism.

  3. Pascal Monett Silver badge

    One hell of a cycle

    Imagine that. Ejecta being brought to the bottom of the sea over millions of years, reabsorbed into the mantle only to be re-ejected millions of years later.

    Talk about a treadmill !

  4. Muscleguy Silver badge


    And of course increasing the CO2 levels in the air and putting more nutrients into the oceans would have fertilised more activity by and more cyanobacteria so producing more oxygen as well. Quantifying that would be difficult at those time distances.

    Also formaldehyde at lowish levels is food for micro bugs as anyone who has used it in the lab knows. Get your solutions too dilute and stuff will grow in it. Those Anatomy museum specimens are in high concentration and often dehydrated to 100% alcohol instead of formalin and they are all completely filled and sealed.

    What took al lot of the time from the first cyanobacteria was that for O2 levels to rise in the atmosphere all the exposed metals in the rocks first had to be oxidised. There's a rust belt in the rocks which precides the great oxygenation event. There might be other on biogenic things going on, but saying we have no idea why they preceded the event is misleading. The rust belt is hard to ignore, just like the iridium from the dinosaur killing meteor.

  5. Ken Hagan Gold badge

    and the isotope ratio?

    What's the process that alters the C12/C13 balance?

  6. Doctor Syntax Silver badge

    Formaldehyde is pretty toxic. Formalin - aqueous formaldehyde solution - is used as a preservative because it inhibits bacteria. In order to be a complete theory hypothesis they need to show how it gets disposed of without using up the oxygen released when it was supposedly formed.

    1. Loyal Commenter Silver badge

      As any fule kno

      CO2 reacts with water to form carbonic acid (H2CO3). You'd have to pump a fair amount of energy in to produce formaldehyde.

      I thought the general explanation for why oxygen didn't immediately build up in the atmosphere is becuase it is fairly reactive stuff, and it would react with anything that would have it first. At this point in prehistory, there were a lot fo reduced iron compounds about (Iron suplhide, IIRC), which reacted with free oxygen to produce Iron oxides, hence the preponderance of red sandstone from this epoch, which is coloured with iron (III) oxide, which is more commonly known as rust. As any geologist will tell you, this stuff is so ubiquitous from that time, that it is known as ORS ("Old Red Sandstone"). It forms the walls and buildings of much of Bristol, and also composes large parts of Australia, such as Uluru.

      1. Doctor Syntax Silver badge

        Re: As any fule kno

        ORS in Britain is much later than that, Devonian. Maybe it's re-sedimentation of material from that era?

  7. Schultz


    I don't have my CRC handbook at hand, but I doubt that CO2 + H2O- - > H2CO + O2 is a spontaneous reaction.

    1. ThatOne Silver badge

      Re: Really?

      Indeed. I didn't read the original paper, but the most vital part of the explanation seems to be missing:

      "Eguchi and his colleagues think the growth of oxygen was triggered by increased levels of carbon dioxide being spewed by newly formed volcanoes."

      As it is, that sounds either like a magic trick ("oh look, there is oxygen in your ear!"), or like something just meant to reassure people about the currently rising CO2 levels ("CO2 good! More CO2 even better!")...

      1. Snowy Silver badge

        Re: Really?

        Or someone is setting up the idea that the rise in CO2 is in part a natural thing?

        1. ThatOne Silver badge

          Re: Really?

          OMG I triggered a climate debate. Sorry everybody, I didn't meant to...

          What I was saying was about CO2 turning spontaneously to O2, how I don't see how and why this might happen (but I admit not being a chemist), and then I made an unfortunate joke about any potential motivation to claim this.

          Sorry again.

          1. Charlie Clark Silver badge

            Re: Really?

            What I was saying was about CO2 turning spontaneously to O2.

            It doesn't. You normally start by reducing it to CO, which is muss easier to work with. If we can ever get this done without photosynthesis in normal conditions, we've solved the energy storage problem for renewables and can stop climate change.

            1. Loyal Commenter Silver badge

              Re: Really?

              If you start producing CO in any quantity, and start chucking it about, you've also solved the problem of most animal life, is that stuff doesn't play nicely with haemoglobin.

              1. Spherical Cow Silver badge

                Re: Really?

                That stuff plays much too nicely with haemoglobin: it won't let go!

              2. Charlie Clark Silver badge

                Re: Really?

                Yes, though it's simply part of two-step reaction and should really be contained. Though a controversial pipeline near here suggests it can be transported safely over distance… In practice any leaks are likely to disperse fairly quickly and be less dangerous than, say, methane links. But there have been cases of mass asphyxiation by both CO and CO2, usually near volcanoes.

                1. Persona Silver badge

                  Re: Really?

                  Before we converted to "North Sea Gas" our homes were powered with Town Gas that was a mix of C0 and H2. We managed to store and transport it down pipes without too many problems. From time to time people did succeed in quickly ending their lives by CO poisoning by sticking their heads in a gas oven. With natural gas it's much harder as they have to rely on asphyxiation ..... as long as the gas isn't ignited.

            2. Intractable Potsherd Silver badge

              Re: Really?

              "... we've solved the energy storage problem for renewables and can stop climate change."

              No, really we can't, any more than our ancestors 10-12k years ago could. Climates change, there is nothing we can (or should) do about it other than have plans to adapt to it.

    2. Charlie Clark Silver badge

      Re: Really?

      It won't be at atmospheric temperature and pressure. Otherwise, these people wouldn't be publishing this paper but setting a company for CCS (carbon capture and sequestration) having solved the CO2 problem.

      They'll need to demonstrate the necessary conditions (pressure and temperature and possibly catalyst) to proceed, and that these could be found in volcanoes, but I remain sceptical. We do know that geological events have indeed had a significant effect on life on earth – the great extinction for example – but this does have something of a rabbit and a hat about it. Quite possibly there was, or were, several events that contributed to the tipping point for a massive expansion of cyanobacteria and photosynthesis.

      But it's still an interesting contribution to the debate.

  8. arctic_haze

    A big misunderstanding

    Sadly, the journalist did not get everything right. No formaldehyde was produced. The reaction on the first page of the paper was supposed to symbolize photosynthesis. Usually people multiply everything by 6 to make the reaction produce glucose which makes more sense. The reason oxygen concentration increased was the same as every other geological time it did. Namely, atmosphere gets richer in oxygen when organic carbon is buried. There is no other way (with the exception of pyrite burying but let's not be too anal).

    I am surprised because all one needs to understood the mechanism is the abstract which says:

    "we demonstrate that about 2.5 billion years ago a tectonic transition that resulted in increased volcanic CO2 emissions could have led to increased deposition of both carbonates and organic carbon (organic C) via enhanced weathering and nutrient delivery to oceans. Increased burial of carbonates and organic C would have allowed the accumulation of atmospheric oxygen while also increasing the delivery of carbon to subduction zones.

    1. ThatOne Silver badge

      Re: A big misunderstanding

      Thanks, that's a bit clearer. Still doesn't explain (to me) where the atmospheric O2 came from in the first place if it weren't for photosynthesis.

      This article seems to suggest that the huge amounts of atmospheric oxygen which appeared back then were partly created out of volcanic CO2 by some geological process also involving volcanoes. Or did I misunderstand everything? *scratches head*

      1. Doctor Syntax Silver badge

        Re: A big misunderstanding

        From what I can make out of the synopsis on-line it is photosynthesis and the argument is that it was out-gassing from volcanoes that raised the carbon-dioxide levels so photosynthesis produced more oxygen. It then depends on the fixed carbon (and hydrogen) being buried and not burned or respired so that the oxygen has a chance of remaining in the air although as said elsewhere in the comments it was initially used up geochemically by oxidising free previously elemental metals.

        And yes, that makes more sense.

  9. bobbear

    Thank goodness for CO2 - it's a pity that there are powerful forces demonising it and intent on getting rid of it. Still, I'm sure we can manage OK without food and oxygen..

    1. Anonymous Coward
      Anonymous Coward


      "I'm sure we can manage OK "

      OK? Potassium oxide?

  10. Danny 2 Silver badge

    What would happen if we combusted every living cell on Earth?

    After this unthinkable planetary immolation, the concentration of oxygen in the atmosphere dropped from 20.9 percent to 20.4 percent. CO2 rose from 400 parts per million to 900—less, even, than it does in the worst-case scenarios for fossil-fuel emissions by 2100. By burning every living thing on Earth...

    The two most abundant gases billowing out of volcanoes are water and carbon dioxide. Photosynthesizers—whether plants, algae, or cyanobacteria—use this raw material to pull off Earth’s greatest magic trick: harnessing photons from a giant thermonuclear explosion 93 million miles away (that is, sunlight), to strip that H2O of its H’s, and add them to that same volcanic CO2, to make the stuff of life. That’s namely stuff with lots of C’s, H’s, and O’s in it, like sugars and carbohydrates, wood and leaves. The O2 left over from this sorcery is released to the environment as waste.

    The Amazon Is Not Earth’s Lungs

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