Author Topic: Methane Breathing Intelligent Lifeforms?  (Read 1414 times)

Offline Triptych

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Methane Breathing Intelligent Lifeforms?
« on: 01/18/2017 05:34 AM »
Just doing a bit of brainstorming for an idea I have. One that involves colonization on a swamp world where the primary inhabitants would be methane breathers. Soo, any exobiologists in this forum?  ;D

My questions: (assuming the planet has earth-like gravity and 1 atmosphere of pressure)

1. Assuming that the inhabitants breathe in methane and eat. Would their waste product be oxygen or another type of gas?

2. Earth atmosphere is 79% nitrogen and about 20% oxygen so what would be the atmosphere of this planet be? I'm thinking it would be 79% CO2 and 20% methane, with trace amounts of oxygen- would that be plausible?

3. Since its a swamp world, it would need plants- is it possible for an alien plant to photosynthesis using oxygen instead of CO2?

4. Assuming that the planet's atmosphere is CO2 and methane, would fires still be possible?

Is any of this plausible or am I overthinking it and I ought to just switch to oxygen breathing aliens instead? What do you think?  ???

Online Ben the Space Brit

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Re: Methane Breathing Intelligent Lifeforms?
« Reply #1 on: 01/18/2017 09:55 AM »
Methane-breathing (and cryogenic fluid-based) life-forms were a staple of the 'Sector General' series of novels by James White, IIRC. One of the hospital's senior consultants, Dr Semlic, was a Vosian, one of said methane-breathing species.


[Edit - Corrected and amplified]
« Last Edit: 01/18/2017 03:52 PM by Ben the Space Brit »
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Offline Oli

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Re: Methane Breathing Intelligent Lifeforms?
« Reply #2 on: 01/18/2017 10:42 AM »

If they breathe methane they must eat oxidizer.

 :)

Offline eric z

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Re: Methane Breathing Intelligent Lifeforms?
« Reply #3 on: 01/18/2017 10:46 AM »
 I know a few semi-intelligent in-laws emitting methane... :-[

Offline Triptych

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Re: Methane Breathing Intelligent Lifeforms?
« Reply #4 on: 01/18/2017 11:01 AM »

If they breathe methane they must eat oxidizer.

 :)
Oh, good point. Do they have to eat this all the time or just with their meals?

(I figure if they have to do this all the time then I would just make the water in the swamps acidic with sulfur and nitrates, or something to that effect.)

Offline sghill

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Re: Methane Breathing Intelligent Lifeforms?
« Reply #5 on: 01/18/2017 01:10 PM »
It would explain the cattle fetish all the UFO's seem to have...
« Last Edit: 01/18/2017 01:14 PM by sghill »
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Online Bynaus

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Re: Methane Breathing Intelligent Lifeforms?
« Reply #6 on: 01/18/2017 01:21 PM »
Breathing = "buring". You will always need a chemical reaction which is exothermic ("energy positive") to "run" your organisms. For Earth-based life, this is basically (but not literally):

CH2O (i.e., some sugar) + O2 <=> CO2 + H2O

CO2 + H2O have less chemical energy than "CH2O" and O2, so reacting the latter will release some energy which the organisms can use.

If you want to "breathe" methane (CH4), you need to react it with something - if that should result in the release of oxygen, whatever that "food" is will have to contain a lot of O. And the whole process should make sense in terms of energy.

There are bacteria on Earth which do not breathe methane, but they produce it as a waste product, the so-called "methanogens". They react CO2 + 4 H2 to CH4 + 2 H2O. In this case, the H2 is found in hydrothermal vents at the bottom of the ocean.

The goal of photosynthesis is exactly the opposite of the reaction above: take water and CO2, produce sugars (used to build up the plant) and release waste oxygen. To make that "energy negative" work, plants have learned to use sunlight to provide the necessary energy. Photosynthesis only makes sense if it yields material which the plant can use to grow, like sugars. So for your plants you would have to find an energy-negative reaction which produces sugars AND releases methane.

At a nearly 1 bar CO2 atmosphere, make sure your planet is far enough from its star, otherwise you might end up with quite a bit of greenhouse warming...

In a CO2 + methane atmosphere, you cannot have fires. You would need oxygen (or another gas you can react the methane or CO2 with) for that.

Offline dchill

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Re: Methane Breathing Intelligent Lifeforms?
« Reply #7 on: 01/18/2017 03:16 PM »
Sorry in advance.  Some things can just can't be unseen.
http://tosh.cc.com/blog/2014/03/01/cool-fart-suit-dudes

[edit - probably okay for 99% of workplaces - performance art(?) with no nudity.]
« Last Edit: 01/18/2017 03:19 PM by dchill »

Offline Triptych

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Re: Methane Breathing Intelligent Lifeforms?
« Reply #8 on: 01/18/2017 03:59 PM »
Breathing = "buring". You will always need a chemical reaction which is exothermic ("energy positive") to "run" your organisms. For Earth-based life, this is basically (but not literally):

CH2O (i.e., some sugar) + O2 <=> CO2 + H2O

CO2 + H2O have less chemical energy than "CH2O" and O2, so reacting the latter will release some energy which the organisms can use.

If you want to "breathe" methane (CH4), you need to react it with something - if that should result in the release of oxygen, whatever that "food" is will have to contain a lot of O. And the whole process should make sense in terms of energy.

There are bacteria on Earth which do not breathe methane, but they produce it as a waste product, the so-called "methanogens". They react CO2 + 4 H2 to CH4 + 2 H2O. In this case, the H2 is found in hydrothermal vents at the bottom of the ocean.

The goal of photosynthesis is exactly the opposite of the reaction above: take water and CO2, produce sugars (used to build up the plant) and release waste oxygen. To make that "energy negative" work, plants have learned to use sunlight to provide the necessary energy. Photosynthesis only makes sense if it yields material which the plant can use to grow, like sugars. So for your plants you would have to find an energy-negative reaction which produces sugars AND releases methane.

At a nearly 1 bar CO2 atmosphere, make sure your planet is far enough from its star, otherwise you might end up with quite a bit of greenhouse warming...

In a CO2 + methane atmosphere, you cannot have fires. You would need oxygen (or another gas you can react the methane or CO2 with) for that.
Thanks, very useful info!  ;D

So I think I got it. The methane breathers will breathe and eat as follows: sugar + carbon + methane + perchlorates (found in swamp water of the planet) = O2

The plant photosynthesis in this world will be as follows: H2 (from anoxic water) + O2 (from animals) + C (sugars) + sunlight (photosynthesis) = methane.

I hope I got this right.  ???

Alternatively I could just go with earthlike plants that produce oxygen, and just have large amounts of methanogen bacteria present in the water to produce methane. But then that would create a problem as to what point would the plants be doing in an ecology that has no use for them.  :o
« Last Edit: 01/18/2017 04:28 PM by Triptych »

Offline sghill

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Re: Methane Breathing Intelligent Lifeforms?
« Reply #9 on: 01/19/2017 01:08 PM »
So I think I got it. The methane breathers will breathe and eat as follows: sugar + carbon + methane + perchlorates (found in swamp water of the planet) = O2

The plant photosynthesis in this world will be as follows: H2 (from anoxic water) + O2 (from animals) + C (sugars) + sunlight (photosynthesis) = methane.

I hope I got this right.  ???

Alternatively I could just go with earthlike plants that produce oxygen, and just have large amounts of methanogen bacteria present in the water to produce methane. But then that would create a problem as to what point would the plants be doing in an ecology that has no use for them.  :o

The "flora" on their world could create hydrogen peroxide instead of perchlorates through a reverse nitrogen cycle! Then there'd be lots of oxidizer in the biomass, but not in the soil.  That would allow "fauna" evolution to take place without constantly fighting against an ever-present oxidizer.  They'd eat the hydrogen peroxide, but not be swimming around in it.
« Last Edit: 01/19/2017 01:09 PM by sghill »
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Offline Triptych

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Re: Methane Breathing Intelligent Lifeforms?
« Reply #10 on: 01/19/2017 03:19 PM »
So I think I got it. The methane breathers will breathe and eat as follows: sugar + carbon + methane + perchlorates (found in swamp water of the planet) = O2

The plant photosynthesis in this world will be as follows: H2 (from anoxic water) + O2 (from animals) + C (sugars) + sunlight (photosynthesis) = methane.

I hope I got this right.  ???

Alternatively I could just go with earthlike plants that produce oxygen, and just have large amounts of methanogen bacteria present in the water to produce methane. But then that would create a problem as to what point would the plants be doing in an ecology that has no use for them.  :o

The "flora" on their world could create hydrogen peroxide instead of perchlorates through a reverse nitrogen cycle! Then there'd be lots of oxidizer in the biomass, but not in the soil.  That would allow "fauna" evolution to take place without constantly fighting against an ever-present oxidizer.  They'd eat the hydrogen peroxide, but not be swimming around in it.

Awesome idea! I guess I can make the plants spew out hydrogen peroxide and methane. Thanks.  :D

Online Lar

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Re: Methane Breathing Intelligent Lifeforms?
« Reply #11 on: 01/19/2017 03:23 PM »
I think you have to have the whole cycle work AND you have to explain why the atmosphere is methane (at least it needs to be valid backstory)...

Looks like a good start on that so far...
« Last Edit: 01/19/2017 03:40 PM by Lar »
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Offline sghill

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Re: Methane Breathing Intelligent Lifeforms?
« Reply #12 on: 01/19/2017 03:29 PM »
So I think I got it. The methane breathers will breathe and eat as follows: sugar + carbon + methane + perchlorates (found in swamp water of the planet) = O2

The plant photosynthesis in this world will be as follows: H2 (from anoxic water) + O2 (from animals) + C (sugars) + sunlight (photosynthesis) = methane.

I hope I got this right.  ???

Alternatively I could just go with earthlike plants that produce oxygen, and just have large amounts of methanogen bacteria present in the water to produce methane. But then that would create a problem as to what point would the plants be doing in an ecology that has no use for them.  :o

The "flora" on their world could create hydrogen peroxide instead of perchlorates through a reverse nitrogen cycle! Then there'd be lots of oxidizer in the biomass, but not in the soil.  That would allow "fauna" evolution to take place without constantly fighting against an ever-present oxidizer.  They'd eat the hydrogen peroxide, but not be swimming around in it.

Awesome idea! I guess I can make the plants spew out hydrogen peroxide and methane. Thanks.  :D

They'd eat the plants for the oxidizer (H2O2) and breathe the methane (for fuel).  We do the reverse.

The plants would spew methane and contain the H2O2 within themselves.  You need to come up with a chemical formula for why.

Perhaps the plants are "floaters" and they use sunlight on their read dwarf, UV-heavy world to convert the H2O2 into H2 in order to fly.  They fly because their world is tidally locked being so close to their small star, so plants can't be stationary.

"Tides" of the floaters will slowly swarm past any methane-breathing animals on the ground, who prey on them for oxidizer as fuel for their metabolism.
« Last Edit: 01/19/2017 03:38 PM by sghill »
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Offline Triptych

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Re: Methane Breathing Intelligent Lifeforms?
« Reply #13 on: 01/19/2017 05:45 PM »

They'd eat the plants for the oxidizer (H2O2) and breathe the methane (for fuel).  We do the reverse.

The plants would spew methane and contain the H2O2 within themselves.  You need to come up with a chemical formula for why.

OK, so far I got this down:

Animals: carbon + methane + hydrogen peroxide = spew out O2

Plants: H2 (in anoxic water) + O2 (animals) + C + photosynthesis = secrete Hydrogen Peroxide and methane.

Methanogen bacteria (living at bottom of shallow seas due to thermal vents) = produce methane

Using this base, there would be no carnivorous lifeforms, all would be either omnivores or herbivores in order to get the hydrogen peroxide to oxidize their cardiovascular systems.

Plants would store hydrogen peroxide in their fruit pods to make animals eat them in order to spread their seeds, I suppose?

I like your floater idea, but it probably wouldnt mesh with the story I'm setting up.  ;)

Star candidate: Gliese 581- previously unknown planet at the outer edge of habitable zone. Since there is massive amounts of CO2 in the atmosphere, it acts a bit like a greenhouse, trapping the heat produced by thermal vents in the water. If it wasnt for the CO2 planet surface would probably freeze.

Since its about 20 lightyears away I'm going to have to invent an FTL drive in order for the humans to get there and colonize it- so thats where the sci-fi comes in.  :P

On a side note: joining this forum was one of the best decisions I ever came up with. This place is a gold mine! I learned so much about science in just a few months of reading the entries here.  ;D
« Last Edit: 01/19/2017 05:58 PM by Triptych »