I had an idea for an alien world I want to set a story on and if this question proves popular I might ask other questions regarding this world.

The world in question is an earth like moon orbiting a gas giant. The moon is earth like in the sense that it’s about the same size and gravity, oxygen nitrogen atmosphere, and plenty of water to support a vibrant biosphere, but that’s where the similarities pretty much end.

Much like Io, this moons proximity to its parent gas giant planet means that the tidal forces creates friction in the core as it orbits, fueling the moons unreal volcanic activity. While a great deal of the planet resembles the Danakil Depression, blood red soil interrupted by vibrant hot springs filled with various extremophile microbes, other areas of the planet are far more like Yellowstone National Park were there are still plenty of hot springs and geysers, but also an abundance of plant and animal life.

I was trying to figure out how the biosphere might work on this alien world one thought stuck out to me that I am having some difficulty trying to answer on my own.

What color would the plants be?

I don’t want the plants to be green because then it might be a little too earth like. And I am man enough to admit I don’t know enough about volcanic material and how plants would incorporate the various gases and minerals and how that would affect color.

So my question is: What color would plants be on an geologically active hot spring planet?

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    $\begingroup$ I imagine the fact it is a hot springs planet would have little to do with the colour of the plants and much more to do with the sun. $\endgroup$ – DKNguyen Mar 30 at 2:07
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    $\begingroup$ The type of sun and atmosphere decide plant pigmentation, not geology. $\endgroup$ – rek Mar 30 at 2:38
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    $\begingroup$ Plants on earth all have the same sun and the same atmosphere and there are marvelous variation in color -- both in shades of green and plants that are not green. $\endgroup$ – Mary Mar 30 at 3:00
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    $\begingroup$ As has been pointed out every time a plant coloration question comes up, you can make them whatever color you want as because the dominate color of plants is due to pure chance. vote to close as a duplicate A more alien world: Flora $\endgroup$ – John Mar 30 at 3:03
  • $\begingroup$ @rek even that has little to do with a plants color $\endgroup$ – John Mar 30 at 3:05

Whatever color you want them to be. Even here on earth, there are a number of pigment chemicals in leaves.

Consider whether they use photosynthesis, or whether they, like the deep-sea sulfur bacteria, live off the vulcanism. (Or, of course, both, in some combination.) You don't have to use chlorophyll for the first, but the second gives you a much freer hand since there are no multicellular life-forms that use that on earth. (Those on earth do use sulfur, which you may want to factor in.)

Also consider the chemicals that plants may produce in order to protect themselves from the heat, or the chemicals spewed from vents. These may also have colors that will in fact dominate to the human's naked eye.

  • $\begingroup$ Not to mention that outside the Chlorophytes there are three other lineages of photosynthesizing organisms which could have been picked by Lady Luck to give rise to the land plants... $\endgroup$ – AlexP Mar 30 at 5:11

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