Methane Photosynthesis

[Vaktus]

One possible energy-yielding reaction in a reducing atmosphere might be the hydrogenation of multiply-bonded molecules - ideally, all the way to methane. For example, although I haven't done the maths I feel this reaction would be exothermic:

C2H2 + 3H2 = 2CH4

(a triply-bonded compound being fully hydrogenated)

This reaction goes very slowly indeed without catalysis, but enzymes do more difficult things than this.

Perhaps this reaction could be used as a reciprocal metabolism? Plants produce hydrogen and animals use that hydrogen to produce methane for the plants to use.

Also, could this reaction also be used for the muuh biosphere Drashner mentioned? Acetylene exists in Titan's atmosphere as well as hydrogen. Acetylene even exist in it's upper atmosphere, I think.

[Vaktus]

Reading over the paper again, the author postulates that instead of using carbohydrates or fats as energy storage, life in this biosphere could gain energy from metabolizing DMSP and turning it into DMS. Plankton preying on phytoplankton do this on earth.

Anyone else think this could be viable? or exist in other biospheres like Muu or Softones?

[extherian]

Rather than patching in these details into the existing Muuh article, we could really do with a dedicated section on methane-ethane biology alone. The tradeoffs involved in producing a workable metabolism at -160 degrees are varied and complex, with our current articles on Methanoids and Muuh lacking in detailed information about how their biology works.

Digestion in particular could end up working very different for methane-based life, depending on what nutrients it needed to survive. They might not require acids to break down their food, or they might digest their food over a period of several months rather than several hours like warm-blooded sophonts.