[Speculative Biology] Sugar/oxidizer reactions with components stable in (possibly aqueous) ammonia


Well-known member
May 10, 2008
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Dallas, TX
In trying to do speculative biology for a sci-fi setting, I've run across the problem that nobody seems to have done a lot of previous well-thought-out speculation on alternatives to oxygen as a biological oxidizer (you'll occasionally see suggestions of fluorine or chlorine, but there seem to be a good number of problems with them, starting, particularly for fluorine, with availability). If you're trying to create a biology that can work in ammonia oceans, this is a problem, because ammonia reacts with oxygen to produce N2 and water, so before oxygen can start to collect in your atmosphere, your oceans are all water and your exotic alien planet looks a whole lot like Earth (it seems halfways possible that Earth's original oceans had a significant ammonia component until photosynthesis became a thing). So I've been looking for oxidizer/sugar reactions (with "sugar" here being any chemical on the reducing side of the equation that is plausible for use in a biological system) that would work in ammonia or ammonia/water solution without eventually eliminating all of the ammonia. I've tried some stab-in-the-dark research on Wikipedia and Google, but enough of my guesses turned out to be touchy explosives (because a lot of the things that don't react with ammonia contain nitrogen, and nitrogen compounds have a tendency to really want to become N2) that I didn't really want to keep guessing and racking up explosives in my search history. So, for anyone with better chemical knowledge than myself, I'm looking for:

1) Decent energy density.
2) At least one of the inputs (can be either the "sugar" or the oxidizer) should be a gas so it can accumulate in the atmosphere.
3) The other input should be a soluble solid or liquid, so it can be stored easily by organisms.
4) None of the inputs or outputs attack proteins, fats, other significant biological molecules (more than oxygen does, at least), or ammonia (at all).
5) None of the inputs or outputs explode.