Specifically, using atmospheric/dissolved sulfur compounds to power energy-producing chemical reactions in Plant-like organisms

Im looking to make a planet where due to a thick cloudy atmosphere, photosynthesis only really exists in the upper atmosphere and chemosynthesis is the primary form of energy production, so "plants" have evolved to use Chemsynthesis instead of Photosynthesis.

EDIT: Was thinking that this world was relatively new (say, 2.5-2.6 billion years old), or the sulfur gets replenished by decomposers releasing the sulfur compounds back into the environment from dead autotrophs, or a series of geothermal activity releases new sulfur along with the compounds being recycled

EDIT 2; ELECTRIC BOOGALOO: When I mean "energy production" I mean it in how it's the baseline for energy in an ecosystem

Edit 3: im sorry for my lack of knowledge in biochemistry, my only real experience with it was a high school biology class I had in freshman year of high school, I was fully and well aware of Chemosynthetic organisms existing on Earth, I'm just curious on if complex, multicellular life based on chemosynthesis is possible and not just Microbes

  • $\begingroup$ Given that there are examples of chemosynthesis on Earth, what makes you think that there would be any impediment to it being the primary form of energy production on a world with some impediment to photosynthesis? $\endgroup$
    – sphennings
    Nov 2, 2022 at 13:54
  • $\begingroup$ Your organisms will eventually run out of sulfur. On Earth they do not run out of CO2 because animals make more, and the energy to power this cycle ultimately comes from the sun. But you say little light reaches the surface on your planet. So where does the energy come from? WHERE DOES IT COME FROM REDFROGCRAB? $\endgroup$
    – Daron
    Nov 2, 2022 at 13:57
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    $\begingroup$ Photo- and chemosynthesis are not forms of energy production. They are forms of energy storage. Both photo- and chemosynthesis need a source of free energy to work; in the case of photosynthesis, that's the light of the sun. Some chemosynthetic organisms here on Earth use the energy supplied by hydrothermal vents. (Note that "free energy" is a technical term; it does not mean energy which can be had for free.) $\endgroup$
    – AlexP
    Nov 2, 2022 at 14:14
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    $\begingroup$ @redfrogcrab no, because then they wouldn’t be plants $\endgroup$
    – Topcode
    Nov 2, 2022 at 15:06
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    $\begingroup$ @redfrogcrab What you have described sounds like tube worms. Immobile multicellular organisms that use chemosynthesis from sulphur vents. $\endgroup$
    – Daron
    Nov 2, 2022 at 15:25

2 Answers 2


Welcome to PLANET EARTH!


The sulfur cycle is a biogeochemical cycle in which the sulfur moves between rocks, waterways and living systems. It is important in geology as it affects many minerals and in life because sulfur is an essential element (CHNOPS), being a constituent of many proteins and cofactors, and sulfur compounds can be used as oxidants or reductants in microbial respiration.[1] The global sulfur cycle involves the transformations of sulfur species through different oxidation states, which play an important role in both geological and biological processes

No fiction here, RFG. The sulfur cycle is real and sulfur metabolizing organisms are alive and well. Probably you have some of these organisms in your colon right now. I certainly do.

You can have sulfur metabolism on your world and lift it intact from terrestrial biochemistry. The only problem for your fiction is you can't totally MSU with the sulfur cycle because informed folks will call you out in the most embarrassing ways. Read up!

getting you started: https://en.wikipedia.org/wiki/Chemosynthesis#Hydrogen_sulfide_chemosynthesis_process

  • 1
    $\begingroup$ Keep in mind that the biogenic chemosynthesis energy turnover is orders of magnitudes lower than the energy turnover of photosynthesis. Chemosynthesis is mostly limited to specialized bacteria/archea and close symbionts/predators (at least on earth). $\endgroup$
    – Matthias
    Nov 2, 2022 at 14:10
  • $\begingroup$ @Matthias - having Old Sol with his deep pockets subsidizing our endeavors is pretty sweet. $\endgroup$
    – Willk
    Nov 2, 2022 at 14:13

Tube Worms

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Tube worms live in the deep ocean where there is no light. The bottom of their food chain is the chemicals and heat from hydrothermal vents or smokers. They are large immobile multicellular organisms that do chemo synthesis.

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The chemo synthesis happens in part due to a bacteria that lives inside the tube worm. The bacteria cannot survive outside the tube worm so it makes sense to consider the tube and bacteria to be a single organism.

This is common in the animal kingdom. I can digest milk with the help of the creepy crawlies in my stomach. But we still just say "I can digest milk" since the creepy crawlies form a useful part of my metabolism.

It is certainly identical from a worldbuilding perspective exactly where the chemosynthesis happens. If you are not happy with symbiotic bacterial colonies and redefining the problem out of existence, then just wait a million years for the bacterium to integrate itself more deeply into the tube ala mitochondria.


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