Discrepancy between oxygen and carbon-dioxide levels

In summary, the conversation discusses the levels of oxygen and carbon dioxide in the Earth's atmosphere and the mechanisms that contribute to their fluctuations. It is believed that oxygen is mostly produced through photosynthesis, but there are other factors such as marine life and the ozone-oxygen cycle that also play a role. The original atmosphere was thought to be mostly composed of CO2, but the current high levels of oxygen cannot be explained by the amount of CO2 available. Possible explanations for this include the sequestration of CO2 by plants, volcanic sources, and anaerobic fermentation. Further research and discussion is needed to fully understand the relationship between oxygen and carbon dioxide levels in the atmosphere.
  • #1
LeBrok
11
0
Does anyone have explanation, or can point me to papers explaining this thread title?

Personally, I did some reading through years, but I could never find an answer to this question.

In short, here is what I learned so far:

Oxygen:
- in free form, is a product of photosynthesis of green life on earth, from combination of CO2 and H2O source.
- is short lived, about 50 thousand years in atmosphere, then it's gone due to oxidation.
- some of O2 is a product of H2O breakdown, when hit by high energy photons, but probably not much.
- 21% of atmosphere is oxygen by volume
- there are some claims that current level of oxygen can be regenerated in 2,000 years!

Carbon-dioxide:
- comes mostly from original Earth's atmosphere, which probably was composed mainly of it.
- in last 500 million years CO2 level is dropping slowly, from about 20 times current level to current level.
- the drop in CO2 level is explained by continues sequestration of it from air to the ground.
- 0.04% of atmosphere by volume


The dilemma is with short lived oxygen in atmosphere. If all current O2 is younger than 50 thousand years, then there wasn't and isn't enough CO2 to recreate it, not even close. Other words, if all oxygen is gone now, all the green life would be able to produce only about 0.05% O2 from all the CO2 available, only a fraction of 21% we have right now.

There is also a claim that states that O2 level was fluctuating between 20-35% in last 500 million years. How is it possible if CO2 volume fluctuated from 1-0.04% of atmosphere?

...or what am I missing?

I can understand CO2 level and depletion through ages. I can't understand O2 level in a light of it's rather short life span in free form.
 
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  • #2
The answer that springs to mind is that there are various mechanisms that remove CO2 form the atmosphere besides photosynthesis. Marine life is constantly depositing CACO3 that comes from H20 + C02 to form H2CO3 and then going through two ionizations to form 2H+ + CO3-2. The carbonate ion combines with a calcium ion to form calcite.
 
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  • #3
comes mostly from original Earth's atmosphere, which probably was composed mainly of it.

The difficulty with this statement is that the atmosphere now is largely composed of nitrogen.

Since there are limited known nitrogen transactions if this gas did not exist in the orignal atmosphere in large quanties, where did it come from.

The Emerald Planet by David Berling

Oxford Unibversity Press

Has a good discussion of the history of the atmosphere, including oxygen.

go well
 
  • #4
Subductionzon said:
The answer that springs to mind is that there are various mechanisms that remove CO2 form the atmosphere besides photosynthesis. Marine life is constantly depositing CACO3 that comes from H20 + C02 to form H2CO3 and then going through two ionizations to form 2H+ + CO3-2. The carbonate ion combines with a calcium ion to form calcite.
Yes, all the sequestration of CO2 from air can explain why there is so little of it after 4 billion years. My problem is that I can't find viable explanation why there is so much of oxygen in relation to CO2, the supposedly main source of it.
Did anyone see any numbers explaining O2 production?
 
  • #5
Studiot said:
The difficulty with this statement is that the atmosphere now is largely composed of nitrogen.

Since there are limited known nitrogen transactions if this gas did not exist in the orignal atmosphere in large quanties, where did it come from.

The Emerald Planet by David Berling

Oxford Unibversity Press

Has a good discussion of the history of the atmosphere, including oxygen.

go well

It looks this way only if one considers that air density was always close to today's one. Most likely original atmosphere was few times denser, maybe even 10 times. This is not very far fetched, if we compare Earth with Venus, which still holds100 times more air.
So, if our original atmosphere was 10 time denser, mostly CO2, then Nitrogen (if constant through ages in volume) was close to 7%. If it was 100 denser then Nitrogen would constitute not even one percent way back.
Unfortunately so far these are just best guesses and speculations. I guess it is extremely hard to measure air pressure from billions years ago.

Thanks for info, I will google David Berling tomorrow.
 
  • #6
I'm not 100% sure what the jist of the question is, but I would suggest that the ozone --> oxygen cycle helps support the constant capture and release of 02. Oxygen is not oxidized, per se, it is broken apart by ultraviolet light. Similarly, ozone can be broken apart by the same wavelengths of radiation to produce oxygen.

Given this you can see that oxygen levels can be built up over long periods of time. It is not simply lost due to oxidation.
 
  • #7
You are treating CO2 as if it had no sources or sinks save sequestration by plants. If this were true plants would have long ago run out of CO2 and the global ecosystem would have collapsed. If we consider sources of CO2 which would not decline with a drastic reduction in O2 partial pressure, volcanic sources immediately come to mind. A quick calculation suggests this would take 10,000 years to restore the CO2. Anaerobic fermentation would release CO2, although it would decline as food sources were depleted. The death of reef-building organisms from lack of oxygen might cause outgassing of CO2 from the oceans.
 

What is the discrepancy between oxygen and carbon-dioxide levels?

The discrepancy between oxygen and carbon-dioxide levels refers to the difference in the amount of oxygen and carbon dioxide present in a given environment. This can occur naturally or as a result of human activities.

What causes the discrepancy between oxygen and carbon-dioxide levels?

The discrepancy between oxygen and carbon-dioxide levels can be caused by a variety of factors, including photosynthesis, respiration, and human activities such as deforestation and burning fossil fuels.

How does the discrepancy between oxygen and carbon-dioxide levels affect the environment?

The discrepancy between oxygen and carbon-dioxide levels can have significant impacts on the environment. For example, an increase in carbon dioxide levels can contribute to global warming, while a decrease in oxygen levels can harm aquatic life.

What are the potential consequences of the discrepancy between oxygen and carbon-dioxide levels?

The consequences of the discrepancy between oxygen and carbon-dioxide levels can include changes in climate, loss of biodiversity, and negative effects on human health. It can also lead to imbalances in ecosystems and food chains.

How can we reduce the discrepancy between oxygen and carbon-dioxide levels?

To reduce the discrepancy between oxygen and carbon-dioxide levels, we can take actions such as reducing our carbon footprint, planting trees, and using renewable energy sources. It is also important to raise awareness and make sustainable choices in our daily lives.

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