Let's create an alien biosphere!

[MathAndCode]

Would you like that to happen?

Yes.

[Schiaparelliorbust]

Yes.

How do you plan to implement it?

[MathAndCode]

How do you plan to implement it?

I don't think that we need to cover the specific steps of each reaction in such great detail.

[Schiaparelliorbust]

I don't think that we need to cover the specific steps of each reaction in such great detail.

So all you want is both CO and CO₂ to be able to be used for the photosynthesis of glycerol. Anything else?

[MathAndCode]

So all you want is both CO and CO₂ to be able to be used for the photosynthesis of glycerol. Anything else?

We need to figure out how quickly carbon monoxide will be depleted.

[Schiaparelliorbust]

We need to figure out how quickly carbon monoxide will be depleted.

How would we calculate that? I think we would need the amount of photosynthetic microorganisms and the rate of photosynthesis, but finding those sounds hard.

[MathAndCode]

How would we calculate that? I think we would need the amount of photosynthetic microorganisms and the rate of photosynthesis, but finding those sounds hard.

We should base it off of estimates for Earth.

[Schiaparelliorbust]

We should base it off of estimates for Earth.

We should probably account for the slightly increased surface area though.

There is a total of 7000 x 109 tonnes of carbon dioxide in the atmosphere and photosynthesis fixes 100 x 109 tonnes per year. So 15% of the total carbon dioxide in the atmosphere moves into photosynthetic organisms each year.

Photosynthetic organisms also convert around 100–115 billion tons (91–104 petagrams) of carbon into biomass per year.

Also, there are no land plants, so we should only use the data for cyanobacteria.

[MathAndCode]

We should probably account for the slightly increased surface area though.

Yes, but there will be proportionally more room for creatures.

We should probably account for the slightly increased surface area though.

There is a total of 7000 x 109 tonnes of carbon dioxide in the atmosphere and photosynthesis fixes 100 x 109 tonnes per year. So 15% of the total carbon dioxide in the atmosphere moves into photosynthetic organisms each year.

Photosynthetic organisms also convert around 100–115 billion tons (91–104 petagrams) of carbon into biomass per year.

Also, there are no land plants, so we should only use the data for cyanobacteria.

See https://en.wikipedia.org/wiki/Great_Oxi ... -atm-2.svg.

[Schiaparelliorbust]

Yes, but there will be proportionally more room for creatures.

Creatures?

See https://en.wikipedia.org/wiki/Great_Oxi ... -atm-2.svg.

Thanks. We will probably have an extra stage because of the absorption of O₂ by CO. We should place it between stages 3 and 4.

[MathAndCode]

Creatures?

organisms

Thanks. We will probably have an extra stage because of the absorption of O₂ by CO. We should place it between stages 3 and 4.

Keep in mind that the early Earth's atmosphere had methane and other gases that dioxygen would react with. Oxygen depleting the methane is believed to have started 2.4 billion years ago, but there is no agreement on when the first oxygen-producing photosynthesizers evolved.

[Schiaparelliorbust]

organisms

That's what I meant. More organisms = more oxygen.

Keep in mind that the early Earth's atmosphere had methane and other gases that dioxygen would react with. Oxygen depleting the methane is believed to have started 2.4 billion years ago, but there is no agreement on when the first oxygen-producing photosynthesizers evolved.

I can't find much on atmospheric methane concentrations over geologic time. Would the oxygen spontaneously react with the methane?

[MathAndCode]

That's what I meant. More organisms = more oxygen.

Yes, so that will cancel out the increased area of the atmosphere. However, the planet's stronger gravity means that the atmosphere will likely be thicker.

[Schiaparelliorbust]

Yes, so that will cancel out the increased area of the atmosphere. However, the planet's stronger gravity means that the atmosphere will likely be thicker.

Yes, that we can be certain of.

[MathAndCode]

Yes, that we can be certain of.

Therefore, dioxygen will accumulate more slowly percentage-wise.

[Schiaparelliorbust]

Therefore, dioxygen will accumulate more slowly percentage-wise.

What about this?

Would the oxygen spontaneously react with the methane?

[MathAndCode]

What about this?

Would the oxygen spontaneously react with the methane?

Yes, it would.

[Schiaparelliorbust]

Yes, it would.

So what are your proposals for how much CO there is in the atmosphere?

[MathAndCode]

So what are your proposals for how much CO there is in the atmosphere?

We agreed upon 6% as a percentage, but we haven't decided the total mass of the atmosphere.

[Schiaparelliorbust]

We agreed upon 6% as a percentage, but we haven't decided the total mass of the atmosphere.

We can probably have a slightly higher pressure than Earth's. Also, I meant proposals for how to apply the change of the amount of CO.

[MathAndCode]

We can probably have a slightly higher pressure than Earth's. Also, I meant proposals for how to apply the change of the amount of CO.

First, we should figure out which order the gases will be depleted in.

[Schiaparelliorbust]

First, we should figure out which order the gases will be depleted in.

Of this list:

40% dinitrogen
20% ammonia
17% carbon dioxide
7% sulfur oxides
6% carbon monoxide
3% hydrogen cyanide
2% hydrogen sulfide
1.5% methane
1.1% water vapor
0.6% ethane
0.6% sulfur oxyacids and oxyanions
0.6% isocyanic acid
0.6% trace gases

there are carbon monoxide, methane, ethane, and hydrogen sulfide which I'm sure will deplete directly because of O₂ in the atmosphere. Are there any others?

[MathAndCode]

there are carbon monoxide, methane, ethane, and hydrogen sulfide which I'm sure will deplete directly because of O₂ in the atmosphere. Are there any others?

ammonia, sulfur dioxide, hydrogen cyanide, sulfurous acid, and isocyanic acid

[Schiaparelliorbust]

ammonia, sulfur dioxide, hydrogen cyanide, sulfurous acid, and isocyanic acid

Would they all deplete at the same time (at different rates) or one after another?

[MathAndCode]

Would they all deplete at the same time (at different rates) or one after another?

Some would react with dioxygen more readily than others, so they wouldn't all be depleted at the same rate.