Let's create an alien biosphere!

[MathAndCode]

I don't ever remember it being S-type, but yes. Can we create out photosynthesizers now?

Sure. The plants will still have access to iron in other metals in the soil, right? If so, they can use them to create conjugated systems that can absorb light energy.

[Schiaparelliorbust]

Sure. The plants will still have access to iron in other metals in the soil, right? If so, they can use them to create conjugated systems that can absorb light energy.

Yes, but aren't we starting with cyanobacteria analogues?

[MathAndCode]

Yes, but aren't we starting with cyanobacteria analogues?

Ah, yes, so they probably won't have as much access to metals. The most elements in Earth's ocean are oxygen, hydrogen, chlorine, sodium, magnesium, sulfur, potassium, carbon, bromine, strontium, boron, calcium, fluorine, and silicon, and increased geological activity in the super-Earth will make sulfur, chlorine, fluorine, and possibly carbon more abundant in the oceans (although not in elemental form). My best idea is that the creatures will use hydrocarbon chains modified with oxygen and possibly one or more of the other common elements in order to absorb light energy. However, keep in mind that the hydrothermal vents will present other source of energy, both due to thermal energy and compounds that could be used as reactants, so life will probably start there as well as for other reasons. Shall we pay attention to those first?

[Schiaparelliorbust]

Ah, yes, so they probably won't have as much access to metals. The most elements in Earth's ocean are oxygen, hydrogen, chlorine, sodium, magnesium, sulfur, potassium, carbon, bromine, strontium, boron, calcium, fluorine, and silicon, and increased geological activity in the super-Earth will make sulfur, chlorine, fluorine, and possibly carbon more abundant in the oceans (although not in elemental form). My best idea is that the creatures will use hydrocarbon chains modified with oxygen and possibly one or more of the other common elements in order to absorb light energy. However, keep in mind that the hydrothermal vents will present other source of energy, both due to thermal energy and compounds that could be used as reactants, so life will probably start there as well as for other reasons. Shall we pay attention to those first?

Yes, let's pay attention to them first. Remember, I made the very massive super-Earth the first planet we had, which had 20% more gravity than Earth, so the surplus of minerals won't be as much.

[MathAndCode]

Yes, let's pay attention to them first. Remember, I made the very massive super-Earth the first planet we had, which had 20% more gravity than Earth, so the surplus of minerals won't be as much.

Let's figure out the reactions. The organisms could oxidize carbon monoxide with sulfate.

[Schiaparelliorbust]

Let's figure out the reactions. The organisms could oxidize carbon monoxide with sulfate.

Would either of those react with water? Maybe something like CO + H2O -> CO2 + H2? Carbon monoxide is unstable.

[MathAndCode]

Would either of those react with water? Maybe something like CO + H2O -> CO2 + H2? Carbon monoxide is unstable.

Yes, that reaction would be energetically favorable.

[Schiaparelliorbust]

Yes, that reaction would be energetically favorable.

Carbon monoxide reacts with water vapour at high temperatures, forming carbon dioxide and hydrogen

They could probably use enzymes or use the heat coming from the hydrothermal vents for this. You also said they can oxidise it with sulfur. So would it be the same reaction but with sulfur in place of the oxygen atoms (except for the one in the CO)?

[MathAndCode]

They could probably use enzymes or use the heat coming from the hydrothermal vents for this. You also said they can oxidise it with sulfur. So would it be the same reaction but with sulfur in place of the oxygen atoms (except for the one in the CO)?

Yes, sulfate can be used as an oxidizing agent.

[Schiaparelliorbust]

Yes, sulfate can be used as an oxidizing agent.

So we've got microbes around hydrothermal vents that oxidise CO with water ad sulfur creating H2 and carbonyl sulfide (both of which are flammable).
It stays like this for a few hundred million years until photosynthesizers evolve.

[MathAndCode]

So we've got microbes around hydrothermal vents that oxidise CO with water ad sulfur creating H2 and carbonyl sulfide (both of which are flammable).
It stays like this for a few hundred million years until photosynthesizers evolve.

They would use sulfate, not elemental sulfur. See https://en.wikipedia.org/wiki/Sulfate-r ... roorganism.

[Schiaparelliorbust]

They would use sulfate, not elemental sulfur. See https://en.wikipedia.org/wiki/Sulfate-r ... roorganism.

Ok, thanks for correcting me. What would the reaction be in that case?

[MathAndCode]

Ok, thanks for correcting me. What would the reaction be in that case?

Actually, I just checked, and while the reaction would be exothermic, it wouldn't be nearly as much so as I thought that it would be, so your reaction is better.

[Schiaparelliorbust]

Actually, I just checked, and while the reaction would be exothermic, it wouldn't be nearly as much so as I thought that it would be, so your reaction is better.

This would create H2 gas then. How much would it be though? Like would it be enough to impact the atmosphere or are hydrothermal vents too rare? Could it be used somehow too?

[MathAndCode]

This would create H2 gas then. How much would it be though? Like would it be enough to impact the atmosphere or are hydrothermal vents too rare? Could it be used somehow too?

Hydrogen gas would definitely be used for something, possibly reducing sulfate (which I verified is significantly exothermic). Also, some volcanoes produce hydrogen gas, so maybe some hydrothermal vents would as well.

[Schiaparelliorbust]

Hydrogen gas would definitely be used for something, possibly reducing sulfate (which I verified is significantly exothermic). Also, some volcanoes produce hydrogen gas, so maybe some hydrothermal vents would as well.

Could you write down the reaction?

[MathAndCode]

Could you write down the reaction?

4 H₂ + SO₄²⁻ ⟶ H₂S + 2 H₂O + 2 OH⁻

[Schiaparelliorbust]

4 H₂ + SO₄²⁻ ⟶ H₂S + 2 H₂O + 2 OH⁻

Thanks. They would then use both this and the reaction I posted to get energy. Would they eat each other too?

[MathAndCode]

Would they eat each other too?

They would probably start doing that eventually.

[Schiaparelliorbust]

They would probably start doing that eventually.

Ok, now let's make the photosynthesizers. To help, I think this is the most recent atmosphere you posted:

Also, here's my proposed atmosphere with 40% dinitrogen:
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

[MathAndCode]

Ok, now let's make the photosynthesizers. To help, I think this is the most recent atmosphere you posted:

Also, here's my proposed atmosphere with 40% dinitrogen:
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

Yes, that looks right. But first, how should life get from the hydrothermal vents to the surface? Maybe geologic activity causes that part of the planet's crust to rise, causing the water to become shallower.

[Schiaparelliorbust]

Yes, that looks right. But first, how should life get from the hydrothermal vents to the surface? Maybe geologic activity causes that part of the planet's crust to rise, causing the water to become shallower.

I actually didn't consider that. Your solution sounds good to me. Maybe they could survive near shallow underwater volcanoes too.

[MathAndCode]

Maybe they could survive near shallow underwater volcanoes too.

Yes, that's possible. I figured that the seafloor would still have hydrothermal vents even after it got closer to the surface (although if they came above the surface, they would become volcanoes). Maybe life can evolve to oxidize the methane and hydrogen sulfide in the atmosphere, as well as already being able to oxidize carbon monoxide.

[Schiaparelliorbust]

Yes, that's possible. I figured that the seafloor would still have hydrothermal vents even after it got closer to the surface (although if they came above the surface, they would become volcanoes). Maybe life can evolve to oxidize the methane and hydrogen sulfide in the atmosphere, as well as already being able to oxidize carbon monoxide.

Okay, what color will they be? I remember you saying that it shouldn't matter much, but I still think we should figure it out. Since both of the suns are similar to ours, I think we can safely assume we will have similar colors there.

[MathAndCode]

Okay, what color will they be? I remember you saying that it shouldn't matter much, but I still think we should figure it out. Since both of the suns are similar to ours, I think we can safely assume we will have similar colors there.

I think that the video that you sent me said that plants don't use green light because their ancestors evolved in a world where the green light was already taken up by organisms closer to the surface. The early life here would probably have a variety of colors.