Study: Fossil fuel formation enabled life as we know it to evolve

From the UNIVERSITY OF WISCONSIN-MADISON, comes this study sure to cause some left-leaning anti CO2 heads to explode. The bold in the PR is mine.

Fossil fuel formation: Key to atmosphere’s oxygen?

MADISON, Wis. — For the development of animals, nothing — with the exception of DNA — may be more important than oxygen in the atmosphere.

Oxygen enables the chemical reactions that animals use to get energy from stored carbohydrates — from food. So it may be no coincidence that animals appeared and evolved during the “Cambrian explosion,” which coincided with a spike in atmospheric oxygen roughly 500 million years ago.

This black shale, formed 450 million years ago, contains fossils of trilobites and other organic material that, by removing carbon from Earth's surface, helped support increases in oxygen in the atmosphere. CREDIT Jon Husson and Shanan Peters/UW-Madison
This black shale, formed 450 million years ago, contains fossils of trilobites and other organic material that, by removing carbon from Earth’s surface, helped support increases in oxygen in the atmosphere. CREDIT Jon Husson and Shanan Peters/UW-Madison

It was during the Cambrian explosion that most of the current animal designs appeared.

In green plants, photosynthesis separates carbon dioxide into molecular oxygen (which is released to the atmosphere), and carbon (which is stored in carbohydrates).

But photosynthesis had already been around for at least 2.5 billion years. So what accounted for the sudden spike in oxygen during the Cambrian?

A study now online in the February issue of Earth and Planetary Science Letters links the rise in oxygen to a rapid increase in the burial of sediment containing large amounts of carbon-rich organic matter. The key, says study co-author Shanan Peters, a professor of geoscience at the University of Wisconsin-Madison, is to recognize that sediment storage blocks the oxidation of carbon.

Without burial, this oxidation reaction causes dead plant material on Earth’s surface to burn. That causes the carbon it contains, which originated in the atmosphere, to bond with oxygen to form carbon dioxide. And for oxygen to build up in our atmosphere, plant organic matter must be protected from oxidation.

And that’s exactly what happens when organic matter — the raw material of coal, oil and natural gas — is buried through geologic processes.

To make this case, Peters and his postdoctoral fellow Jon Husson mined a unique data set called Macrostrat, an accumulation of geologic information on North America whose construction Peters has masterminded for 10 years.

The parallel graphs of oxygen in the atmosphere and sediment burial, based on the formation of sedimentary rock, indicate a relationship between oxygen and sediment. Both graphs show a smaller peak at 2.3 billion years ago and a larger one about 500 million years ago.

“It’s a correlation, but our argument is that there are mechanistic connections between geology and the history of atmospheric oxygen,” Husson says. “When you store sediment, it contains organic matter that was formed by photosynthesis, which converted carbon dioxide into biomass and released oxygen into the atmosphere. Burial removes the carbon from Earth’s surface, preventing it from bonding molecular oxygen pulled from the atmosphere.”

Some of the surges in sediment burial that Husson and Peters identified coincided with the formation of vast fields of fossil fuel that are still mined today, including the oil-rich Permian Basin in Texas and the Pennsylvania coal fields of Appalachia.

“Burying the sediments that became fossil fuels was the key to advanced animal life on Earth,”

Peters says, noting that multicellular life is largely a creation of the Cambrian.

Today, burning billions of tons of stored carbon in fossil fuels is removing large amounts of oxygen from the atmosphere, reversing the pattern that drove the rise in oxygen. And so the oxygen level in the atmosphere falls as the concentration of carbon dioxide rises.

The data about North America in Macrostrat reflects the work of thousands of geoscientists over more than a century. The current study only concerns North America, since comprehensive databases concerning the other 80 percent of Earth’s continental surface do not yet exist.

The ultimate geological cause for the accelerated sediment storage that promoted the two surges in oxygen remains murky. “There are many ideas to explain the different phases of oxygen concentration,” Husson concedes. “We suspect that deep-rooted changes in the movement of tectonic plates or conduction of heat or circulation in the mantle may be in play, but we don’t have an explanation at this point.”

Holding a chunk of trilobite-studded Ordovician shale that formed approximately 450 million years ago, Peters asks,

“Why is there oxygen in the atmosphere? The high school explanation is ‘photosynthesis.’ But we’ve known for a long time, going all the way back to Wisconsin geologist (and University of Wisconsin president) Thomas Chrowder Chamberlin, that building up oxygen requires the formation of rocks like this black shale, which can be rich enough in carbon to actually burn. The organic carbon in this shale was fixed from the atmosphere by photosynthesis, and its burial and preservation in this rock liberated molecular oxygen.”

What’s new in the current study, Husson says, is the ability to document this relationship in a broad database that covers 20 percent of Earth’s land surface.

Continual burial of carbon is needed to keep the atmosphere pumped up with oxygen. Many pathways on Earth’s surface, Husson notes, like oxidation of iron — rust — consume free oxygen.

“The secret to having oxygen in the atmosphere is to remove a tiny portion of the present biomass and sequester it in sedimentary deposits. That’s what happened when fossil fuels were deposited.”


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January 3, 2017 11:14 am

The alarmists will seize on this paper because it is actually alarmist:
Today, burning billions of tons of stored carbon in fossil fuels is removing large amounts of oxygen from the atmosphere, reversing the pattern that drove the rise in oxygen.
Well that sounds just awful, doesn’t it? Let’s do the numbers.
Pre-industrial CO2 ~ 280 ppm
Pre-industrial O2 ~ 200,000 ppm
If we assume the extra CO2 we now have (400 ppm) removed O2 from the atmosphere at a 1:1 ratio, we get:
Current O2 ~ 199, 880 ppm
Change of 0.006 %
In other words, a change so small we would be unlikely to be able to measure it at all. Yet the article represents burning of billions of tons of carbon as being significant. This is the insanity of alarmism writ large. An absolutely inconsequential change being touted as danger batman danger when it is obvious from the credentials and skill sets of the authors that they know very well their alarm is absolute twaddle.

Reply to  davidmhoffer
January 3, 2017 11:16 am

You were faster.

Keith J
Reply to  davidmhoffer
January 3, 2017 12:08 pm

But each carbon atom ties up two oxygens. Since ppm is most often mass, that is significantly more oxygen..about 32/12.
And in photosynthesis, it is indeed carbon dioxide which is reduced. After all, carbohydrate is the product and that is a portmanteau of carbon and water.

Reply to  Keith J
January 3, 2017 12:13 pm

But each carbon atom ties up two oxygens.
Aside from the fact that if you were correct, the difference would still be so small as to be amusing. But let me spell out your error:
1. Number of O in molecule of O2 = 2
2. Number of O in molecule of CO2 = 2

The Original Mike M
Reply to  davidmhoffer
January 3, 2017 12:13 pm

Oxygen is nearly half the weight of the earth and I think the biggest share of it is tied up in iron oxide?

Thomas Homer
Reply to  The Original Mike M
January 3, 2017 12:52 pm

More than water?

Reply to  The Original Mike M
January 3, 2017 1:00 pm

Water. Then carbonates. Then mineral oxides. There is more limestone than iron ore.

Nick Stokes
Reply to  The Original Mike M
January 3, 2017 1:33 pm

“the biggest share of it is tied up in iron oxide”
No, mostly silicates (rock). Silicon is easily second most abundant, and every silicon atom is linked to at least two oxygen.
But the key think is oxidation status. The point of this article is that photosynthesis and burying carbon leaves oxygen free.

The Original Mike M
Reply to  The Original Mike M
January 3, 2017 2:32 pm

Thomas Homer “More than water?” – No, water is a very rare substance on earth, most all of it is on or in the crust which has a comparative thickness proportional to the skin of an apple.
Nick Stokes – “No, mostly silicates (rock).” That makes sense.

Reply to  The Original Mike M
January 3, 2017 3:35 pm

MM, even though it seems to make sense, it isn’t right if you research the geological minerology. Most inorganic minerals deep in the crust are chemically reduced by heat. Diamonds are a splendid example. An iron ore converter furnace provides- surface xample. Simple chemistry.

Nick Stokes
Reply to  The Original Mike M
January 3, 2017 5:09 pm

“Most inorganic minerals deep in the crust are chemically reduced by heat. “
Heat can’t reduce anything. For that you need a reductant. An iron ore converter consumes carbon. If it gets hot enough, an oxide like FeO will decompose into Fe and O2. But that then liberates oxygen. There is no reason to think it is an ongoing process with net oxygen production. In the surface layers that we interact with, the vast bulk of the matter is oxides or oxide equivalents (like alumino-silicates).

Reply to  davidmhoffer
January 3, 2017 12:37 pm
Daniel Stolper and his colleagues at Princeton University have used records of ancient air trapped in polar ice cores to determine the concentrations of oxygen (O2) in the atmosphere over the past 800,000 years. They found that oxygen concentrations have declined steadily over this time period by a total of 0.7% relative to the current atmospheric oxygen concentration (i.e., the oxygen content of atmosphere has decreased from 21.1% of all molecules in air 800,000 years ago to its current value of 21.0%).
Abstract: The history of atmospheric O2 partial pressures (Po2) is inextricably linked to the coevolution of life and Earth’s biogeochemical cycles. Reconstructions of past Po2 rely on models and proxies but often markedly disagree. We present a record of Po2 reconstructed using O2/N2 ratios from ancient air trapped in ice. This record indicates that Po2 declined by 7 per mil (0.7%) over the past 800,000 years, requiring that O2 sinks were ~2% larger than sources. This decline is consistent with changes in burial and weathering fluxes of organic carbon and pyrite driven by either Neogene cooling or increasing Pleistocene erosion rates. The 800,000-year record of steady average carbon dioxide partial pressures (Pco2) but declining Po2 provides distinctive evidence that a silicate weathering feedback stabilizes Pco2 on million-year time scales.

Reply to  davidmhoffer
January 3, 2017 1:23 pm

Agree David – there is NO risk we will run out of oxygen by burning fossil fuels.
Note that fossil fuels also enabled humanity to end its greatest scourge – that of slavery.
Before we had fossil fuels, we had animal power – humans and other beasts of burden. That is how wealthy people lived in luxury, and great civilizations built their monuments, buildings and infrastructure.
Without fossil fuels, we would still be living in these cruel times – fully 86% of global primary energy is STILL provided by fossil fuels – oil, coal and natural gas. Renewables provide less than 2%, despite huge subsidies.
I work in the fossil fuel industry. When challenged by idiot greens, I politely explain to them that fossil fuels keep their families from freezing and starving to death.
Best, Allan

Joe Crawford
Reply to  Allan M.R. MacRae
January 4, 2017 10:41 am

When challenged by idiot greens, I politely explain to them that fossil fuels keep their families from freezing and starving to death.

It’s a crying shame they never learned to think past the first level of indirection. Oh well… so much for today’s educational system.

Nick Stokes
Reply to  davidmhoffer
January 3, 2017 1:42 pm

“In other words, a change so small we would be unlikely to be able to measure it at all.”
Oxygen depletion is routinely measured. It mirrors the variation in CO2, and is one of the arguments that establishes that burning C is indeed the source of the extra CO2 in the air. But yes, we won’t run out.

Reply to  Nick Stokes
January 3, 2017 5:42 pm

That was a short fascinating post and link, Nick. It is wonderful to have one intelligent warmist in this crowd, and the graph in that link is indeed strong evidence that the increased CO2 in the air comes from “burning C.” I believe that most of the C that is burned is coming from abuse of farm soil, and a little from dams. Of a certainty, some comes from fossil fuels, also.
It matters where the C is coming from. Carbon dioxide is beneficial in itself, and not just as plant food. Increased concentrations benefit animal physiology as well, including the human body. But much of the world’s soil has been –sterilized — and that bodes ill indeed for the future. So long as the greens are distracted by nonsense about temperature, they can do nothing to heal the actual damage that is occurring.
The Paris climate delegates left excited as they realized that sequestering carbon in soil is doable. I was also excited, because organic matter enrichment makes soils more fertile, and the plants more drought-resistant. There are also indications that the local climate is improved too, but moderating daily temperature swings.
Would it be possible to get YOU to investigate “regenerative agriculture,” and work with greens on these things?

Reply to  davidmhoffer
January 3, 2017 8:15 pm

Yes, that is how alarmists work : they never do the numbers.

January 3, 2017 11:16 am

Today, burning billions of tons of stored carbon in fossil fuels is removing large amounts of oxygen from the atmosphere, reversing the pattern that drove the rise in oxygen. And so the oxygen level in the atmosphere falls as the concentration of carbon dioxide rises.

billions! waa!
There is a couple of tons O2 per m², and 4PI R² of surface, where R >> 1e6 m. That’s more than 1e14 tons. Yeah, panic.

Keith J
January 3, 2017 11:20 am

If oxygen were a few percentage points higher, fires would be uncontrolable. A few points lower and fires woudn’t stay lit.
Nature’s stability is no accident.

The Original Mike M
Reply to  Keith J
January 3, 2017 12:21 pm

“If oxygen were a few percentage points higher, fires would be uncontrolable. ”
And bugs would become a lot larger too.

Reply to  Keith J
January 4, 2017 10:01 pm

How many is “a few”?
What do you mean, “uncontrollable”?
There have been times when the O2 content of the atmosphere was much higher…more than a few points.
Fires occurred during these periods, and there was no one to control them, and yet they did not burn forever.
And fires stay lit at altitude, where there are far fewer molecules of oxygen in a given volume of air.
You seem to be saying that the amount of oxygen in the air today is where it is by design.

January 3, 2017 11:22 am

It was not so long ago that Boston was piping raw sewage into the ocean. I guess they were ahead of their time.

January 3, 2017 11:34 am

The arithmetic doesn’t work. It is estimated that if we burned all the fossil fuels, the CO2 concentration in the atmosphere could rise to 1400 ppm. That’s 0.14%. In that light, fossil fuel creation doesn’t come close to explaining why there is so much oxygen and so little carbon dioxide in the atmosphere.
What am I missing?

Reply to  commieBob
January 3, 2017 11:50 am

That’s the recoverable fraction of fossil fuels (with current or foreseeable technology). There is a lot more carbon in organic compounds that we will never be able to recover and burn (profitably).
However, the authors are missing (or ignoring) many very important factors here – one of the biggest being the sequestration of carbon into non-organic forms, such as calcium carbonate. Also, the fact that the geologically recent tectonic movements have created very deep oceans, deep enough for significant amounts of methane clathrate to form.

Keith J
Reply to  Writing Observer
January 3, 2017 12:14 pm

Spot on. Clathrates are the greatest organic carbon sink. The explaination for missing carbon and the reason Dr Martin’s iron seeding had a short lived effect.

Reply to  Writing Observer
January 3, 2017 1:04 pm

Except for agiogenic in the Framm Strait seafloor spreading, almost all methane clathrate is biogenic rather than thermogenic and is along continental shelves. There is thermogenic from natural gas seeps in the deep Gulf of Mexico. Essay Ice that Burns has details.

Reply to  Writing Observer
January 3, 2017 7:51 pm

My understanding of methane clathrates is that they form at a certain pressure and temperature. My question is what happens when there is an ice age? Do they all boil off and the earth gets a blast of methane to the atmosphere,if so wouldn’t that cause a spike of CO2 and a cooling of the oceans?

Reply to  Writing Observer
January 3, 2017 11:18 pm

You forgot iron. When oxygen first started to be liberated, the oceans literally rusted. Once the most chemically active things had finished reacting, that left free oxygen available to be released to the atmosphere. I don’t know how long it took though, so I can’t comment on how it aligned with the start of the Cambrian.

Reply to  commieBob
January 3, 2017 12:28 pm

Commie, I think the answer to your questions is; Oxygen does not come from the CO2 molecule, it comes from the H2O molecule. As long as there is water, CO2 does not have to be in high concentrations for O2 to be produced. It is not a one to one relationship. Below is a simple explanation.

J Mac
Reply to  commieBob
January 3, 2017 12:32 pm

Calcium carbonate aka ‘limestone’ is a large carbon sink, as are soft and hard shales, chalk deposits (the White Cliffs of Dover), and all coral reef structures (also calcium carbonate).

Roger Graves
Reply to  J Mac
January 3, 2017 1:14 pm

Calcium carbonate is a CO2 sink, not a carbon sink:
CaO + CO2 = CaCO3
The vast bulk of carbon on or near the surface of the planet is tied up in various forms of carbonate rocks, including both calcium and magnesium carbonates. However, the process sequesters O2 as well as C, so I fail to see how the overall oxygen balance is changed by this.

Reply to  commieBob
January 3, 2017 1:00 pm


Leo G
Reply to  commieBob
January 3, 2017 1:44 pm

Geologists tell us that the source of atmospheric oxygen is the slow zonal recomposition of iron oxides in the outer core and the mantle.

January 3, 2017 11:35 am
Articles originaux qui ont été traduits en français et qui seront publiés sur Résistance 71:
2ème partie:

Reply to  ratuma
January 3, 2017 12:24 pm

The two links deal with the theory that oil and gas do not come from formerly living organisms (biogenic) but, rather, from geological (abiotic) processes.

Curious George
January 3, 2017 11:36 am

An uninformed speculation. Probably all oxygen in the atmosphere got there as a byproduct of the photosynthesis – plants convert CO2 to O2. Why should we stop converting carbon to CO2? It is a part of a natural cycle.

Steve Heins
Reply to  Curious George
January 3, 2017 11:51 am

George, technically plants do not release the oxygen from CO2 into the atmosphere. The energy from light is used to split the oxygen off of a water molecule which is then released into the atmosphere. The Calvin cycle uses the leftover hydrogen in sugar synthesis with the CO2.

Reply to  Steve Heins
January 3, 2017 12:20 pm

and when we oxidize crap the H2O comes back to complete the circle….

Reply to  Curious George
January 3, 2017 3:40 pm

Actually, that is very informed. Oxygen is highly chemically reactive. (fire). So absent persistent photosynthesis, would not exist as a free molcule. For details, see my technical comment which just mysteriously appeared after hours in non-moderation, I think below, but whatever. Science does not change by blog comment position.

January 3, 2017 11:41 am

This report is spectacularly off base. They seem to assume all CO2 removed from Earth’s atmosphere us now in organic deposits. The vast majority is now rock (coral strata, limestone, and other sedimentary carbonates). Without accounting for that they seem to imply the tiny effect of burning fossil fuels threatens our oxygen supply – not even close to reality.

Reply to  andrewpattullo
January 3, 2017 11:53 am

I should remember to read all of the comments first… Should have know that the people here would pick that one up first thing.

Reply to  andrewpattullo
January 3, 2017 3:50 pm

The first sink for oxygen was dissolved iron in the primordial seas. Earth’s early atmosphere had massive amounts of carbon dioxide, resembling Venus, this was sequestered into carbonate rocks. That was possible for Earth because Earth had oceans of water even early on.
Unless the theory changed since I last read about reconstructions of very early Earth.

January 3, 2017 11:42 am

An example of the shortfall of narrow education.

Reply to  Dan Pangburn
January 3, 2017 2:47 pm

Amen. A thousand times amen.
So often we see scholars saying things that most reasonably educated people would know better than to say. I am a skeptic because Dr. Mann tried to erase the MWP and LIA. A smattering of history knowledge would have saved him the embarrassment.

Michael Perse
January 3, 2017 11:48 am

But the Permian and Pennsylvanian periods were well after the Cambrian explosion; their sediments might be examples of the process, but can’t be examples of the cause of earlier oxygen increase. And the end stage for the Permian is punctuated by the greatest mass extinction ever, with considerable evidence of a substantial drop in atmospheric oxygen. This hypothesis seems shaky to me.

Reply to  Michael Perse
January 3, 2017 2:59 pm

I had a longish comment on this that disappeared. Google ‘GOE’ or the ‘great rusting’. Google stomatolites. The paper is vastly oversimplistic.

Reply to  ristvan
January 3, 2017 3:09 pm

Has just mysteriously appeared below despite not being in moderation.

Reply to  Michael Perse
January 5, 2017 7:28 pm

Look at the OP: some researcher amassed a data set that includes many data sets.
Then, he found two measures that have a similar zig and zag across their apparent time span (500 million years).
I am surprised the rise of fish is not implicated as well, since this is quite a fishing expedition.
How many measures did he have at his disposal from which to find such coincidences? We will know as he gets his pubs out in the next year or two.

January 3, 2017 11:51 am

I have to remain skeptical about this alleged correlation between sedimentation rates and O2 concentration. First of all, look at the lack of data preservation. How much of the Earth’s surface from 500 Mya exists today? How much of the Earth’s surface from 2.3 Bya exists today. Most of it has been eroded, subducted, or metamorphosed.
You do not need sedimentation to prevent carbon from being converted into CO2. You can also have anoxic deep sea beds that accumulate carbon rich material that will later be overlain by sediments or evaporates.
I think there is also a problem with the theory. If sedimentation rate has something to do with O2 concentration, the sedimentation rate would better correlate with the d(O2)/dt rate and not the O2 concentration per se.
The O2 concentration begins to rise when the reacting agents, such as Fe get used up in the environment. The deposition of the banded iron-beds have more to do with later growth in free molecular O2 in the atmosphere than any sedimentation correlation. IMHO.

Reply to  Stephen Rasey
January 4, 2017 10:24 pm

I think it just takes photosynthesis. The oxidizing iron simply slowed the buildup of free oxygen until all the iron was used up.
Once the Earth was overspread by photosynthesizing organisms, the buildup of O2 was a foregone conclusion, as water was gradually converted to O2.
Carbon gets recycled in the biosphere, but also buried and converted to carbonates, but it is also being vented from volcanos.
But the plants and algae just keep churning out more O2, every day the sun is shining.

Brian R
January 3, 2017 12:03 pm

Leftist and eco-mentalist work the long play and I think you’re missing the long play with this article. By linking biomass sedimentation to an increase in O2 levels in the atmosphere, they can then effectively say that burning of fossil fuels will lower the amount of available O2 in the atmosphere, thus destroying life as we know it.
Never take anything a Leftist or eco-mentalist says at face value.

January 3, 2017 12:13 pm

The real and credible threat is CO2 going below 150ppm and everything dies. Talk about apocalypse.
The problem is that the earth is cooling and there are less volcanoes now to replenish CO2 being sucked up by hard-shelled sea creatures. Looking back at several glaciations between the inter-glacials we see a trend of declining CO2, with the last time it hit 180ppm.
Patrick Moore explains this here:
Human CO2 Emissions are Wholly Beneficial – Dr Moore:

The Original Mike M
January 3, 2017 12:17 pm

Plants are apparently not the only source of our oxygen supply.
{We estimate that this source so far provided an amount of oxygen equivalent to eight to ten times the mass of oxygen in the atmosphere,“ says Bykova. “That’s a surprise, and it is not quite clear what happens with the oxygen down there.”}

Reply to  The Original Mike M
January 4, 2017 10:35 pm

They seem to be saying that oxidized iron arrived at the mantle by subducted red bed formations, which formed from the oxidation of iron, which was present in the early ocean, as plants and algae began to churn out free O2.
Then the call this deep oxygen a “source” of oxygen?
But they do not seem to be saying that this oxygen winds up in the atmosphere.
And in any case, it could not have been a source of oxygen before the banded iron formations existed, and were subsequently subducted.
A clue to what they are getting at may be found in the last paragraph:
“Our work shows that we maybe miss significant parts of the processes in the Earth. Subducted slabs can apparently produce unexpected things. The effects on Earth’s global dynamics, including climate variations, have to be investigated.”
Translation…we need more money.

John Boles
January 3, 2017 12:21 pm

Well then we should all stop burning carbon, except for the elites in academia, et al.

Peta from Cumbria, now Newark
January 3, 2017 12:30 pm

Without any clear timeline in my mind:
Many billions years ago, when plants first started making oxygen, would that oxygen not have been ‘consumed’ by any iron lying around (would it be Fe2+ being converted into Fe3+)
There’s plenty iron out there, any red coloured dirt or red pigments in paint/whatever, that’s iron you’re looking at giving that colour.
But then, tadaaaa, there was a Tipping Point (innit great when you know the lingo) when all the iron in the surface layers of primeval dirt was oxidised and used up.
So, dead plant material would then be oxidised, in the surface layers, by oxygen ‘breathing’ bacteria. This produces quite potent organic acids that attack the rock particles.
Two effects from this are:
1. Lots more plants from all the trace elements coming out of the dissolved rock – fertiliser basically.
2. Lots more small & tiny pieces of rock that can be washed away by rainwater, carried by rivers and eventually settle out in very slow moving water of lakes and estuaries – creating lovely layers of sediment for scientists to drill holes into and dig out fossils.
What’s not to like?

Reply to  Peta from Cumbria, now Newark
January 3, 2017 2:36 pm

Maybe nit picking, but there were no actual plants two billion years ago. The photosynthetic organisms of that eon were cyanobacteria, aka blue-green “algae” (which they aren’t). Animals evolved before plants.
The press release is also wrong about when animals “appeared and evolved”. Every year we find more and more Precambrian animals. Some modern phyla have been IDed in the Ediacaran Period, last before the Cambrian.
Molecular clocks suggest that animals (eukaryotic, multicellular, motile heterotrophs) first appeared 750 to a billion years ago, and of course have been evolving ever since. The oldest definite animal fossils are of tiny sponges from more than 600 Ma. Biochemical evidence of sea sponges dates from 640 Ma, about 100 million years before the Cambrian.
Oxygen levels did increase in the Cambrian, but were already high enough in the Ediacaran and earlier Cryogenian (720 to 635 Ma, a Snowball Earth interval) Period of the Neoproterozoic Era for animals to appear and evolve.
Fungi are eukaryotic, uni- and multicellular heterotrophs, more closely related to animals than plants. Plants are eukaryotic, multicellular autotrophs. There is no good reason why single-celled fungi are included in their kingdom but only multicellular animals and plants in ours. The closest unicellular organisms to animals are choanoflagellates (with “collars” to catch bacteria for food), which form colonies, resemble sperm cells and are practically identical to the feeding cells of sponges. Since yeast count as fungi, choanoflagellates should be rated animals rather than “protists”, a paraphyletic grouping. Maybe amoebas, too.

Reply to  Peta from Cumbria, now Newark
January 3, 2017 5:50 pm

My reply is lost in the ether, apparently.
Short version is that there were no actual plants two billion years ago. The main photosynthetic organisms then and for long after were cyanobacteria.
Noted also that the press release is wrong about when animals appeared and evolved. They were around long before the Cambrian, although did need free oxygen in the air and water. The Oxygen Catastrophe also occurred long before the Cambrian, but O2 did increase in that period, first of the Phanerozoic Eon and Paleozoic Era. Every year we find more Precambrian animals, including some which belong to extant phyla.

Jerry Henson
January 3, 2017 12:42 pm

Confusing cause with effect is common.
As has been observed in our present atmosphere, increased CO2 in the atmosphere
increases plant growth which increases photosynthesis which increases O2.
If the attached graphs are correct, they clearly show ~550 MYA high CO2 levels
allowed an explosion of photosynthesis which lead to high levels of atmospheric O2.
High levels of CO2 in the atmosphere were probably caused by warm oceans not
being able to keep up with the microbial oxidation of hydrocarbons
or the tectonic action of reprocessing of carbonate rock layers.
The above observations are correct. It is hydrocarbons, not fossils.
Dying plants do not get a chance to collect on the ocean floor to form hydrates.
They are consumed by microbes in real time. The spill from Deep Water Horizon
was consumed when researchers looked for the plume three months after the
spill was stopped. The microbes bloom to the extent of the food available.

January 3, 2017 12:58 pm

While not incorrect per se, this study omits two major additional factors.
1. We know from stromatolite fossils that photosynthetic life (probably cyanobacteria ancestors) were forming shallow seawater stromatolite mats at about 2.3bya. This placed oxygen in the air and started the ‘great rusting’, aka GOE. This oxidized inorganic igneous minerals (most abundantly iron, calcium, and silicon) and formed the great Mesabi and Pilbaran iron ore deposits. That process pretty much ran up to the Eidcarian ~700 mya. As the GOE stopped (everything was oxidized) oxygen could build up enabling Edicarian multicellular organisms. Those rapidly diversified as oxygen further builtup, including an arms race that involved evolution of exoskeletons and eyes, during the Cambrian explosion starting ~540mya withmfossils from the Burgess shale.
2. By far the greatest sequestration of carbon is in calcium carbonate formed by marine organisms like coccoliths and diatoms. It is not in TOC, some of which converts to usable fossil fuels. Were it not for recycling of carbonates back into volcanic minerals plus CO2 along tectonic subduction zones, life would long since have ceased as atmospheric CO2 would have fallen below minimum photosynthetic thresholds ~150ppm. The oldest limestones date to the Paleozoic, which began with the Cambrian explosion. Carbonates are ~10% of all sedimentary rock (rest is mainly sandstones (weathered igneous quartz), and shales (weathered igneous feldspar clays) both of which do not have a primarily biological origin and started forming much earlier). Geology and mineral collection is my hobby since 40+ years.
So, while it is true that carbon sequestered in buried organic matter helped build the atmospheric oxygen we enjoy today, it is not the primary mechanism. Everything had to rust first. And then a race between biological sequestration and tectonic release began. Organic sourcerock shales from which oil and natural gas form, and coals are one of two basic biological sequestration mechanisms. The White Cliffs of Dover are an example of the other.

Jerry Henson
Reply to  ristvan
January 3, 2017 3:11 pm

Were it not for hydrocarbons forming deep in the earth and continuously up welling
and being oxidized either by microbes, enriching the soil or being converted by the
atmosphere to CO2, the CO2 in the atmosphere would not support the life that we
currently see on earth.

Reply to  Jerry Henson
January 3, 2017 3:27 pm

Jerry, sorry. This is a science blog. Other than relatively rare geologic abiogenisis of methane you have exactly zero science to support your assertion. which makes no sense from first chemical principles, anyway. What works on very cold Encladeus does not work on relatively warm Earth. Oil is biogenic. Get ovr it. So it is finite in the sense of the biology of Earth. Period. The arguement is over when, not if. You compare the moon of a distant gas planet to rocky inner planet, better learn some planetary science. Learn, or go away.

David Ball
Reply to  Jerry Henson
January 4, 2017 12:15 pm

Ristvan sounds like the alarmists when the CO2 thing started. Dogmatic.

Reply to  ristvan
January 3, 2017 6:05 pm

In my AO (NE WA State), Early Cambrian to Middle Ordovician limestone and dolomite abound.
Remarkable how much of the Paleozoic stuff still crops out around the world.

Thomas Homer
January 3, 2017 1:01 pm

“For the development of animals, nothing — with the exception of DNA — may be more important than oxygen in the atmosphere.”
Carbon is essential for carbon based life forms (includes animals).

January 3, 2017 1:11 pm

I consider the fact that the O2 we all use was CO2 before photosynthetic life the most Duh aspect of this Big Dumb Lie . See .

Juan Slayton
Reply to  Bob Armstrong
January 3, 2017 1:25 pm

Bob, if I read the comments above correctly, the O2 we all use was H2O before photosynthetic life.

Reply to  Juan Slayton
January 3, 2017 1:48 pm

Admit I only scanned it ( because the bottom line is nothing new ) but how you split which molecules in
6 CO2 + 6 H2O => C6H12O6 + 6 O2
the 6 O2 came from is beyond my pay grade .

Reply to  Juan Slayton
January 3, 2017 3:13 pm

Nope. The main photosynthetic answer is CO2. Photosynthesis does not split water. It splits CO2, because energetically bound. The it adds the freed carbon to water to create hydrocarbons. HYDROCARBONS. Hydro as in water plus Carbons. Hence the chemical class name.

Reply to  Juan Slayton
January 3, 2017 5:55 pm

The O2 released by photosynthetic organisms comes from water. In the light reactions, two hydrogen ions are split from the oxygen atom in a water molecule. The H ions attach to CO2 molecules, which also join together, through a number of intricate steps in the dark reactions to make sugar, while O2 molecules are released into the air or water.

Reply to  Juan Slayton
January 3, 2017 6:22 pm

Heck Bob, even if you never took a single class in biochemistry, you can always just look it up.
The exact chemical pathway of each atom in the process of photosynthesis is well known.
Chimp got it right.
The oxygen comes from the original water molecules.
The Calvin cycle (light independent) part of the reaction reproduces some water from the hydrogen left over from the light dependent part of photosynthetic process, plus some oxygen that was part of the original CO2.

Reply to  Juan Slayton
January 3, 2017 7:35 pm

Dunno how this paragraph in the press release got published:
“In green plants, photosynthesis separates carbon dioxide into molecular oxygen (which is released to the atmosphere), and carbon (which is stored in carbohydrates).”
What really happens, greatly simplified, is that energy from the sun splits water molecules into atoms of H and O. The oxygen is released as the molecule O2, while the hydrogen atoms combine with CO2 molecules to form sugar, a carbohydrate containing atoms of C, H and O.
Also, animals (eukaryotic multicellular, motile heterotrophs) existed before the Cambrian. Long before. Someone with elementary life science education should have edited this press release.

Reply to  Juan Slayton
January 4, 2017 1:48 am

Photosynthesis is a biochemical process that converts carbon dioxide gas into sugars. The sugar contains hydrogen and this element is derived from the water. The free oxygen in the Earth’s atmosphere is therefore sourced from the water molecules and NOT from the oxygen atoms in the carbon dioxide molecules.

It is generally agreed that the net reaction for green plant photosynthesis can be represented by the equation
CO2 + H20 +hv -> O2 + (1/n)(C.H20)n
and also that very little is known about the actual mechanism. It would be of considerable interest to know how and from what substance the oxygen is produced. Using O18 as a tracer we have found that the oxygen evolved in photosynthesis comes from water rather than from the carbon dioxide

See:- Ruben, S., Randall, M., Kamen, M. and Hyde, J.L., 1941. Heavy oxygen (O18) as a tracer in the study of photosynthesis. Journal of the American Chemical Society, 63(3), pp.877-879.

Nick Stokes
Reply to  Juan Slayton
January 4, 2017 11:54 am

“Heck Bob, even if you never took a single class in biochemistry, you can always just look it up.”
Bob got it right. The actual mechanism of the reaction involves many steps. The fact that it takes isotope analysis to determine whether the O2 came from water or CO2 also tells you that it doesn’t matter, else there would be other chemical evidence of the distinction. The plants do not produce hydrogen. Bob’s reaction shows the inputs and outputs.

Reply to  Juan Slayton
January 4, 2017 9:03 pm

Got what right Nick?
For the record, I never said he got anything wrong, just that is it is known where the oxygen which is liberated comes from.
It comes from the water.

Reply to  Juan Slayton
January 4, 2017 9:46 pm

Nick Stokes,
With this statement: “The fact that it takes isotope analysis to determine whether the O2 came from water or CO2 also tells you that it doesn’t matter, else there would be other chemical evidence of the distinction.”
my opinion of your scientific acumen dropped sharply.

Nick Stokes
Reply to  Juan Slayton
January 5, 2017 4:45 am

“just that is it is known where the oxygen which is liberated comes from”
OK, then what difference does it make?

Reply to  Juan Slayton
January 5, 2017 11:59 pm

Bob Armstrong
The standard equation you show 6 CO2 + 6 H2O => C6H12O6 + 6 O2 is highly confusing to all because it implies that half of the atoms in the released oxygen gas have come from the carbon dioxide molecules.
Sugar is formed from carbon dioxide gas by the addition of hydrogen from water. The hydrogen is released from the water by photo dissociation. This complex organic process can be better understood if we equate the stage forming the oxygen gas to the inorganic formation of a single hydrogen peroxide molecule from two water molecules with the release of two hydrogen atoms 2(H20) -> HOOH + 2H. The release of the oxygen gas molecule then occurs with the conversion of two hydrogen peroxide molecules back to water 2(HOOH) -> 2(H2O) + O2.
This illustration of the process starts with four water molecules, it generates 4 hydrogen atoms from these water molecules, returns two water molecules back from the hydrogen peroxide molecules and liberates one molecule of oxygen gas. So far so good, but please remember this explanation is just an illustration of a more complex process.
The chemical description of sugar as having a base unit of CH20 “carbon water” is also misleading. Simple sugars, such as the 6 carbon atom glucose molecule are formed of carbon chains. Carbon has a valence of 4 and forms the spine of the chain, Oxygen has a valence of 2 and Hydrogen has a valence of 1, so the only way to link these three atoms together to create the basic unit of the glucose chain is to form the chemical species HCOH. A better way to think of this chemical structure is that simple sugars are a polymer of methanol (the simplest possible alcohol) with two of the three hydrogen atoms linked to carbon in the methanol base unit replaced by covalent bonds to adjacent carbon atoms.
But we are still missing where some of the oxygen atoms have gone to.
I recommend that you read this superb post by plantguy Plants Don’t Convert CO2 into O2 (H/T Duncan) to find the answer:-

Bottom line: Green plants DO NOT convert carbon dioxide (CO2) into oxygen (O2). The oxygen produced during photosynthesis comes from water. During photosynthesis, green plants DO, however, convert atmospheric CO2 into sugars. And we know now that one half the oxygen atoms in the CO2 wind up in the sugars (e.g., glucose = C6H12O6) and the other half wind up in phosphate byproducts of the Calvin Cycle. During the so-called “Reduction Phase” of the Calvin Cycle, ATP is used to phosphorylate the 3-PGAs, and then NADPH is used to reduce (add electrons) the 3-carbon compound to produce GAP. In doing so, one of the phosphate (PO43-) groups is removed, containing one of the original oxygens from the CO2.

Reply to  Bob Armstrong
January 3, 2017 6:12 pm

Um…a hydrocarbon contains hydrogen and carbon.
A carbohydrate, of which glucose is one, contains hydrogen and oxygen in the same proportion as they exist in water, and add carbon.
The product of photosynthesis is a carbohydrate, from which all the proteins and lipids, and other carbohydrates, are synthesized.
Just sayin’.

Rob Bradley
Reply to  Menicholas
January 3, 2017 6:20 pm

Proteins are not synthesized from carbohydrates. Carbohydrates do not contain nitrogen, but proteins do. Hint: proteins are synthesized WITH not “from” carbohydrates.

Reply to  Menicholas
January 3, 2017 6:20 pm

Correct. A hydrocarbon isn’t the same as a carbohydrate, eg the hydrocarbon methane (CH4) v. the carbohydrate glucose (C6H12O6).

Reply to  Menicholas
January 3, 2017 6:27 pm

That’s a valid distinction. Proteins are polymers of peptides, ie chains of amino acids, which are compounds formed from side chains bound to a central (alpha) carbon atom. These side chains include a carboxyl group -COOH, an amine group -NH2, an atom of hydrogen -H and a variable radical -R, that is the functional group of the amino acid. In glycine, the radical is simply another H atom.

Reply to  Menicholas
January 3, 2017 6:27 pm

With, not from!
Ooh, OK.
Without the carbohydrates and the energy they contain, there are no proteins.

Reply to  Menicholas
January 3, 2017 6:34 pm

My point, re proteins and lipids, had to do with the energy, not the molecules or the source of each atom.
Obviously there are many additional atoms that are incorporated into essential biomolecules.
But all of the energy, all of it, every last bit, comes from the solar energy stored in the glucose which is the product of the basic photosynthesis equation.
That was muh point.

Rob Bradley
Reply to  Menicholas
January 3, 2017 6:40 pm

Menichoolas says: “But all of the energy, all of it, every last bit, comes from the solar energy stored in the glucose”
Not true, for example the carbohydrates used by the hydro thermal vent organisms deep on the ocean floor do not use solar energy.

Reply to  Menicholas
January 4, 2017 9:54 am

Yep , sorry . sloppy .

Reply to  Menicholas
January 4, 2017 9:01 pm

Well, you got me there Rob.
Is “Changing the Subject” a degree program nowadays?

Reply to  Menicholas
January 4, 2017 9:07 pm

BTW, in case it was not apparent, my comment re hydrocarbons vs carbohydrates was in reply to Dr. Istvan stating that hydrocarbons are water plus carbon.
They are not.
Carbohydrates are.
My response to him went into the wrong place.

Reply to  Menicholas
January 4, 2017 10:15 pm

Chimp, the carboxylic acid from which amino acids are constructed is an organic molecule, and the carbon in them is fixed from the atmosphere via photosynthesis.
And the energy to produce the ammonia from fixed nitrogen likewise became available to the biosphere by the photosynthetic production of glucose.
Without this step, none of these other molecules could exist.
Plants and animals use the energy and carbon from glucose to make everything else that contains energy and carbon.
(Unless you subsist of deep ocean vent tubeworms)
I am not sure what the point of disputing this is?

January 3, 2017 1:41 pm

a full blown professor, who masteminded something he calls Macrostrat, and a post doc came up with this…..
oh Lord help us all………..

Smart Rock
January 3, 2017 2:18 pm

Anthony – can you provide a link? I wouldn’t mind looking at their data.
Strip away the mandatory reference to AGW and there could be some useful info.

January 3, 2017 2:49 pm

I would guess that sequestration of carbon in fossil fuels is insignificant compared to that by limestone, chalk and other carbonate and carbon containing sedimentary rocks.

Berényi Péter
January 3, 2017 2:54 pm

Today, burning billions of tons of stored carbon in fossil fuels is removing large amounts of oxygen from the atmosphere, reversing the pattern that drove the rise in oxygen.

About 0.05% of atmospheric oxygen was removed so far by burning carbon in fossil fuels. That’s not a “large amount” by any standard.
Moreover, I do not think free atmospheric oxygen was produced by burial of organic material, the amount of it is far too small in the crust. It is much more likely, that it comes from water by photolysis and Hydrogen escape to space.
In an atmosphere dominated by a triatomic gas, like carbon dioxide, there is no tropopause, no cold trap, no stratosphere, convective currents go all the way up to ToA (Top of Atmosphere), carrying large amounts of water vapor with them. What is more, there is no ozone layer, so energetic UV radiation can penetrate all the way down to the surface.
Only ten feet of ocean water had to undergo photolysis to produce the current oxygen rich atmosphere. That amount is undetectable in the geologic record.

Jerry Henson
January 3, 2017 3:51 pm

, 3:27 PM As I previously said, I will demonstrate my findings to you with you calibrating
and operating the test instruments. Are you willing to learn something from actual
empirical evidence rather than theory and models?

Reply to  Jerry Henson
January 3, 2017 4:48 pm

Jerry Hensen, Yah, sure. Are you are on the Swedish failed drilling mud or the failed Ukranian false (overthrust) Russian experiment or something else. If you bring those, you lose. Got something else not in the literature? Bring it. With all the orher isotopic evidence. Do not confound abiogenic methane (yup a little bit) with abiogenic petroleum (nope, no where, ever.)
So, bring all your evidence on. Please. Losing would be wonderful for humanity. Except it is not possible.

Reply to  ristvan
January 3, 2017 5:47 pm

How did Comet Halley acquire it’s oil shale–kerogen–under your theory of hydrocarbon origins?
Why do experiments with diamond anvils produce crude oil from marble and water at high temperature/pressure regimes mimicking conditions at 100 km depths?
“Bring it. With all the orher [sic] isotopic evidence
What isotopic “evidence” did you ever bring to the table?
“Khwarizmi, You are right about methane and hydrocarbons…
-Ferdinand Engelbeen

Jerry Henson
Reply to  ristvan
January 3, 2017 5:59 pm

Rud As I said, I will drive to your farm and we can do an actual test. No theory,
no bluster, just a scientific experiment. How about it?

Reply to  ristvan
January 3, 2017 6:32 pm

ristvan, the abiotic oil theory is Russian, and most of the publications are in Russian. This is a very difficult language for English-speakers. When some Americans heard of it, they rehashed the ideas so badly that they sounded ridiculous. I have read discussions by those who understood the chemistry. The arguments are very sound, essentially proof–SOME oil is from fossils, but most is produced deep in the Earth’s crust under temperatures in the thousands K and many atm pressure, enormous pressure. Under those conditions, petroleum is the most stable state.
A good reference site if you are familiar enough with the principles of chemistry is
It is believed that Life originated in the deep ocean. Abiotic oil meeting sea water would be very far indeed from equilibrium and easily powered the emergence of life.

Reply to  ristvan
January 4, 2017 9:16 pm

Some believe life originated in the deep ocean.
But there is no direct evidence for this.
To many, it is more likely life originated in space, or on some other planet, and simply floated to Earth at some point.
After all, there is far more time and space, and hence greater chances for biogenesis by uncounted orders of magnitude for this scenario.
If, that is, one happens to believe inanimate stuff sprang to life all by itself.
There may be a way to gather evidence for this hypothesis: If and when life is discovered elsewhere, and if it happens to be DNA based and share properties of Earth life, or not, this may give some strong clues or even constitute proof one way or the other at some point.

Jerry Henson
January 3, 2017 6:22 pm

Rud, Upland topsoils, soil not in a floodplain, in the presence of adequate moisture,
owe their richness to the amount of natural gas up welling through them.
I tested, I did not model or theorize.
Lets do a test.

January 3, 2017 7:06 pm

Yup, that plate tectonics theory is nuts! Whoever heard of moving continents? utter nonsense!

Reply to  Mike Borgelt
January 3, 2017 7:23 pm

To be fair to geologists before c. 1960, it was continental drift which they found nuts. Once plate tectonics was established, and the mechanism for “drift” discovered, ie sea floor spreading, the Old Guard fell into line sooner than they did for the Missoula Floods and similar massive outbursts from ice-dammed lakes (jökulhlaup).

Reply to  Chimp
January 4, 2017 9:24 pm

True, but consider all of the evidence which was pooh-poohed for many decades prior to the discovery of the mid-oceanic ridges.
The close match of the continental margin alone would be an impossible coincidence. The fact that, when the continents are lined up according to these matching margins, there happen to be identical rock strata, with identical fossil sequences does, IMO, constitute proof.
One has to be willfully ignorant to disregard this evidence. Rather than discarding the idea because no mechanism was known, a mechanism could have or should have been sought, rather than marginalizing anyone who argued the evidence.
The entire story is a very good illustration of how so-called experts are often anything but real experts…that they often are and have been blind to truth and unbending in their dogma.

January 3, 2017 7:25 pm

Ultimately all of the carbon on Earth is from the dust and gas that the Sun and planets condensed from (apart from a little from carbonaceous chondrites since). Likely the carbon was in the form of methane as that molecule seems to be prevalent in space (where did the methane on Titan come from?) Some of it got trapped under the crust and in the mantle and being lower density than its surroundings will percolate to the surface. For life to use it it had to first arrive in regions where life molecules could survive (deeper than you’d think at first).
So it’s a no brainer that ALL the carbon is from inorganic sources. Life may have used some of it along the way and left evidence.
Presence of fossils or microbes in oil is not proof that the oil was formed by living matter which died. Your average microbe on encountering oil probably thinks: “yum! unoxidised carbon and hydrogen!”
ladylifegrows, read some of the late Tommy Gold’s books on the subject. He was not at all dogmatic, was open to being proved wrong and proposed some experiments for up and coming geologists. I haven’t heard if anyone has done them.

January 3, 2017 7:31 pm

If the mechanism I described was happening in the primordial Earth, when did it stop? if it didn’t stop it is still happening and AFAIK experimental evidence exists of abiotic formation of longer chain hydrocarbons from methane under conditions found deep in the Earth.

January 3, 2017 9:05 pm

I suggest reading “The Deep Hot Biosphere, The Myth Of Fossil Fuels”, by Thomas Gold, with a Foreword by Freeman Dyson. ISBN 978-0-387-95253-6.

Steve T
Reply to  nabbiz
January 4, 2017 6:19 am

January 3, 2017 at 9:05 pm
I suggest reading “The Deep Hot Biosphere, The Myth Of Fossil Fuels”, by Thomas Gold, with a Foreword by Freeman Dyson. ISBN 978-0-387-95253-6.

Thomas Gold was fluent in Russian and appears to have plagiarised the Russian/Ukrainian theory of abiotic oil and gas production adding in some additional (possibly incorrect) thoughts. If you have time it is well worth reading and following the links at which give a very thorough layman’s introduction for anyone prepared for a bit of work. There are a few complicated bits but these can be lightly skipped over without losing the thread of the argument. It is well worth bookmarking and reading when time permits. Warning, if you are curious, the introduction might ensnare you to spend time you hadn’t planned!
I am astonished that Ristvan, whose comments I have read for years and been impressed by his apparent knowledge, should think that “the science is settled” on this topic. I can’t believe that he thinks there is no calcium carbonate, iron oxide and water being subducted into the mantle. The link above gives details of experimentation which demonstrate that at the temps and pressures at that depth, chains of hydrocarbons found in crude oils are the natural, stable result from just these three common materials. They could then be brought nearer the surface and trapped, waiting to be found in much the same way as diamonds are.

January 3, 2017 11:15 pm

Rocks dude rocks…. Everything is chemically bonded in rocks.

Alan Tomlin
January 4, 2017 7:37 am

Ristvan, who is usually very sensible and thoughtful and well informed really missed on the photosynthesis-O2 source (water, not CO2)….as soon as I read his comment, I did a “yikes, don’t think so”

Rod Everson
January 4, 2017 8:00 am

The last quote in the article reads: ““The secret to having oxygen in the atmosphere is to remove a tiny portion of the present biomass and sequester it in sedimentary deposits.”
Sounds to me like an endorsement for landfilling our waste instead wasting so much time (and energy) sorting it out.

Peter Foster
January 4, 2017 11:26 am

2 points.
First – not only does O2 come from water but the light phase of photosynthesis is relatively independent of the dark phase. The hydrogen from water, along with the electrons, is stored in the form of two high energy carriers, When these reduced carriers are too high in proportion to the oxidised forms then the energy is wasted by side reactions in order to restore some of the oxidised forms.Typically most plants waste about 50% of the energy gained by these carriers so that the rate at which oxygen is formed is about double that needed to produce the carbohydrate formed in the dark phase.
Secondly, if one looks at oxygen levels from mid Devonian to the Permian, they rose from 15 to 25% coinciding with the decline in atmospheric CO2 but after CO2 had stabilised at around 300 ppm, O2 continued to rise steeply from 25 to 35% coinciding with the beginning of the Ice Age around 320 mya.
I suspect that this was due to ice sheets covering the land and preventing eroded iron from reacting with oxygen. That is, plants continued to produce oxygen from photosynthesis but its removal by oxidation of minerals was hugely reduced allowing oxygen to accumulate.
At the end of the ice age at 275 mya O2 plummeted back to 15% as the ice uncovered the minerals.
This started the extinctions, loss of atmospheric oxygen then allowed sulphur bacteria to produce hydrogen sulphide so that the already anoxic oceans became poisoned, accelerating the extinctions.During this time CO2 increased mainly from decomposition of the dead. The Siberian traps volcanoes did not start until near the end of the extinctions.
The key point of all of this is that oxygen dropped so dramatically because there was not enough CO2 in the air. Plant growth, slowed and inhibited by low CO2, was insufficient to maintain oxygen levels.
The great Permian extinction did not happen at 252 mya, it had been accelerating for some 15 million years before that. The extinctions ended at 252 mya when CO2 was rising through the 1600 ppm mark. The Increasing CO2 levels allowed increased plant growth that first slowed the decline in oxygen and then, several million years later reversing it.
This is the lesson for today when once again plant growth is slow due to low CO2 and oxygen is declining because oxidation exceeds the capacity of plants to replace it.
CO2 is the most important molecule for life on Earth. Without CO2 there are no plants, without plants there is no photosynthesis, without photosynthesis there is no food and there is no oxygen.Without those, higher life forms cannot exist.

January 4, 2017 9:35 pm

I find it very surprising that in such a paper, which explores the how and why carbon was sequestered in increasing amounts during the carboniferous period, no mention is made of the reason why the carbon was became so difficult to oxidize…the development in plants of cellulose and especially lignin, and that is took a very long time for other life forms to develop the enzymes need to break these down.
In those days, plants had far more lignin, many times more, and it was impervious to biological decomposition for many millions of years.
I wonder if the authors are unaware of this basic fact?

Jerry Henson
January 5, 2017 11:49 am

@Rud For your enjoyment—-Horsehead nebula and hydrocarbons.

Tim the plumber
January 7, 2017 8:25 am

I thought that calcium carbonate, limestone, deposited on the sea floor was where most carbon was sequestrated.
Perhaps the rate at which carbon comes out of volcanoes is not constant?

Jerry Henson
Reply to  Tim the plumber
January 7, 2017 12:20 pm

Tim, The sea floor is where most carbonates are sequestered. The layers that you see
as you descend the Grand canyon are mostly carbonates, 200+ million years worth.
volcanoes do not recirculate it nearly fast enough to keep CO2 levels in the atmosphere
to support life as we know it on earth.
Up welling hydrocarbons being oxidized by microbes, enriching the topsoil as they die,
or hydrocarbons escaping into the atmosphere to be oxidized there are the mechanisms
which give the atmosphere adequate CO2.

Johann Wundersamer
January 10, 2017 8:48 am


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