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19 votes
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When did wildfires start to occur on earth?

A definitive statement comes from the abstract of Scott and Glasspool1, 2006: Charcoal, a proxy for fire, occurs in the fossil record from the Late Silurian (≈420 Myr) to the present. One of the ...
Spencer's user avatar
  • 3,548
12 votes

Is oxygen the most abundant element on Earth?

Both of them. The composition of the atmosphere, crust, mantle, core and bulk earth are all notably different. The atmosphere is composed of ~78% nitrogen and ~21% oxygen, with small amounts of ...
bon's user avatar
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8 votes
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Why is it said that Amazon creates 20% of the oxygen production of the world, when it accounts with less than 14-12.8% of the forest area?

I cannot find any language in peer-reviewed literature (as far as publicly accessible) that makes the 20% claim reported in the question. I therefore consider this claim to be of obscure and dubious ...
njuffa's user avatar
  • 558
8 votes
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Could earth run out of O2?

No, that will not happen. There is just too much oxygen in the atmosphere. Over 20% of our atmosphere is oxygen. Only about 0.04 % of our atmosphere is CO2, so too much CO2 would kill us much sooner ...
vsz's user avatar
  • 464
8 votes

Why did the carboniferous period have so much atmospheric oxygen?

The Carboniferous was when the growth of woody plants took off. Non-plant life had not yet evolved the ability to consume lignins, the key chemical components that makes woody plants "woody". Lignins ...
David Hammen's user avatar
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7 votes
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Why is Great Oxidation Event associated with Iron oxidation but not Aluminum or Silicon?

Because Al and Si were already oxidised to begin with. When the Earth formed, it had some amount of metals (Fe, Si, Mg, Al, Ca, etc) and a fixed amount of oxygen to bond with those metals. Certain ...
Gimelist's user avatar
  • 23.1k
6 votes

Why cannot people burn all the atmospheric oxygen?

Photosynthesis has not stopped. It happens all the time, splitting water and carbon dioxide, and producing oxygen and carbohydrates. Likewise, organic matter rots and decomposes all the time, ...
Wolfgang Bangerth's user avatar
6 votes
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Why did the carboniferous period have so much atmospheric oxygen?

To complement @DavidHammen answer and address the point "where did so much oxygen come from?" I will elaborate on David's final remark The end result was a gradual increase in oxygen levels The ...
Camilo Rada's user avatar
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5 votes

Why is it said that Amazon creates 20% of the oxygen production of the world, when it accounts with less than 14-12.8% of the forest area?

Do we need to worry about oxygen? No. Although some reports have claimed the Amazon produces 20% of the world’s oxygen, it is not clear where this figure originated. The true figure is likely to be ...
Keith McClary's user avatar
5 votes

How is the equilibrium of 21% oxygen in Earth's atmosphere established?

Atmospheric oxygen is not in an equilibrium of 21%, it just changes very slowly. For instance, oxygen has decreased by 0.7% over the past 800 thousand years, likely due to increased erosion (which ...
f.thorpe's user avatar
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5 votes
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Why limestone formation was not a concern in atmosphere oxidation event?

First, let me clarify this again: Al2O3 is not clay. Now, back to topic. You are mixing apples and oranges here. The geological section you are referring it was deposited 2 billion years after the GOE....
Gimelist's user avatar
  • 23.1k
4 votes

Why cannot people burn all the atmospheric oxygen?

If I understand it right, you are assuming that in the beginning we had CO2, which was then split to organic carbon and O2 via photosynthesis. And now you are asking if it's possible to reverse all of ...
Gimelist's user avatar
  • 23.1k
4 votes

Causes of fluctuations in atmospheric oxygen in past 300 Mya

Here's a somewhat different looking graph, from Oxygen and Evolution, Robert A. Berner et al., Science 316, 557 (2007): The graph shows three marked drops in O2 levels, each corresponding to an ...
David Hammen's user avatar
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3 votes
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How much nitrogen would you need to replace all oxygen in a room of 1,000 cubic feet?

Your assumption about constant pressure can't actually exist while everything is closed. I am not using this assumption here because it is more correct and a bit easier: $$\pu{10 feet} = \pu{3.048 m}$$...
User123's user avatar
  • 638
3 votes
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What rate of deforestation would be needed until we run out of oxygen?

As Jan points out, there are many other factors in the oxygen balance, not just trees. But for a bit of fun, let us suppose that we burn all the trees on the planet. The global biomass of carbon is ...
Gordon Stanger's user avatar
3 votes

Is oxygen spread equally on Earth's surface?

Based upon links from a similar question on atmospheric distribution in Chemistry SE, I looked into the latitudinal difference by making a couple images using the MSIS model chemistry plotting website ...
JeopardyTempest's user avatar
2 votes

Percentage of Oxgen left after burning all the available biomass

Estimates of earth's total biomass vary widely, from 0.5 to 4 trillion tons C, so instead of citing a source, I'll just go with an assumption of $1\times10^{15} \text{kg C}$. Measuring biomass in ...
kingledion's user avatar
  • 3,376
2 votes

Is oxygen the most abundant element on Earth?

"How can this be reconciled?" In two words: silicon dioxide :-) Yes, that's simplistic, but reflects the fact that virtually all the oxygen occurs in chemical combinations with other elements, not ...
jamesqf's user avatar
  • 1,748
2 votes

Are we consuming more oxygen than the world is producing due to fossil fuels?

Yes, atmospheric oxygen is being depleted by fossil fuel burning. From https://cdiac.ess-dive.lbl.gov/trends/oxygen/modern_records.html - Oxygen concentrations are currently declining at roughly 19 ...
Ken Fabian's user avatar
  • 2,056
2 votes

How many mole of oxygen gas is there in the atmosphere?

It is easier to calculate: The pressure of air on the ocean level is $\approx 100 \rm {kPa}$. Thus, its weight is $\approx$ 100000N over $1 \rm m^2$. Considering that the overwhelming majority of the ...
peterh's user avatar
  • 660
2 votes

Terraforming and maintaining a habitable atmosphere on Mars

It depends on what gases one wants the atmosphere to contain. Mars has a lower gravitational acceleration than Earth, mainly due to is smaller size. This lower level of gravity, combined with the ...
Fred's user avatar
  • 24.7k
1 vote

How could oxygen levels have ever been higher if there is so little carbon dioxide present?

It doesn't go anywhere, you don't need CO2 production to loose oxygen. photosynthesis is water + CO2 into O2 and sugar. In this case the sugar is mostly cellulose. what happened in the carboniferous? ...
John's user avatar
  • 6,906
1 vote

Filtered pressured oxygen 80 miilion years ago

What filter? Modern vertebrate blood is always red (with just one exception AFAIK: https://en.wikipedia.org/wiki/Channichthyidae ) because it is based on hemoglobin. Given that birds, which descend ...
jamesqf's user avatar
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1 vote
Accepted

What was the oxygen concentration in the air during the late miocene period?

R. Tappert et al (2013) used carbon isotopes in ambers as proxies for atmospheric oxygen concentrations. Their work indicates an initial Miocene O2 concentration of 16% and rising to about 20% at the ...
Knob Scratcher's user avatar
1 vote

Are we consuming more oxygen than the world is producing due to fossil fuels?

Since pre-industrial times $CO_2$ has increased from 280 to 415 ppm. Considering only carbon (ignoring the hydrogen in hydrocarbons), atmospheric $O_2$ decreased by the same amount, 135 ppm. The ...
Keith McClary's user avatar
1 vote

Why does atmospheric oxygen remain so "constant"?

The main reasons the atmospheric oxygen remains constant are: The sheer quantity of it. Not even a large forest fire will measurably deplete it. Most of it is fossil oxygen created many millions of ...
Michael Walsby's user avatar
1 vote
Accepted

Are there any consequences to carbon capture and storage that also sequesters oxygen?

No, I think there are not. At least not at the scale of the proposed projects. I say this just because $\text{CO}_2$ makes up only a 0.04% of the atmosphere, so even if you burn fossil fuels until you ...
Camilo Rada's user avatar
  • 17.6k

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