Hydrogen Peroxide As Biological Solvent
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Basic Information

Water is an amazing chemical. Here on earth, it has proven to be a key ingredient in life, serving as a biological solvent, helping insulate and maintain temperatures, and being a major byproduct of photosynthesis. However perfect water is for life, it is ill suited for planets with very low temperatures. Water turns to ice, and when this happens inside an organism, the results are painful and often lethal.

Life In The Frozen Desert

However, in various solutions, the freezing point of water can be much lower. A 61.2 percent (by weight) mix of water and hydrogen peroxide has a freezing point of -56.5 degrees Celsius, and also tends to super-cool rather than crystallize. Life that utilized such a blend would be very resistant to cold.

Hydrogen Peroxide is Hygroscopic, meaning it attracts water to it. This would not only help create the mix mentioned above, it would also be helpful for life trying to find water in an arid environment. Life using Hydrogen Peroxide in addition to water would have a two-fold advantage in a desert. Not only would it survive on less water, it would have a chemical system very adept at leeching water out of the atmosphere.

Such life may begin as standard water-using life as we know it, and then evolve to use hydrogen peroxide or a mixture. This would allow life to survive if the planet it was on cooled off, dried out, or both. It has been proposed that exactly this sort of scenario has happened on Mars, and is the reason for the results of the Viking Biological Experiments.

Alternative Photosynthesis

On earth, photosynthesis is produces gaseous oxygen from the carbon dioxide in our air. However, similar chemical reactions exist that could produce liquid hydrogen peroxide instead, and would still generate energy. So, plant-analogs may exist on other worlds that produce hydrogen peroxide - whether it would be released as a gas or liquid depends on atmospheric pressure and temperature. For more on the biochemistry of alien plants, see non-green photosynthesizers.

Other Properties

In addition to staying liquid at much colder temperatures, and sucking water out of things, Hydrogen Peroxide has several other remarkable properties.

It's acidic and oxidizing, and has bleaching properties. On earth, it's used as an antiseptic to kill germs and fungus. Life making use of Hydrogen Peroxide in large quantities would have to be very hardy and resilient, and may have a somewhat acidic nature. It's biochemistry may be mildly harmful to us, and it would likely be very resistant to earth bacteria.

Because of the way hydrogen peroxide attracts and extracts water, it may turn out that large quantities of water are very hazardous to peroxide life forms. They may absorb water rapidly through their membranes. Immersion in water may be enough to cause such life to bloat up and possibly even rupture. Having your cells swell and explode is a nasty way to go.



Game and Story Use

  • As mentioned above, if life exists on Mars, it's very likely it will use hydrogen peroxide to supplement water.
  • Hydrogen Peroxide was used as a propellant in the early 20th Century, but eventually abandoned because of it can sometimes explode. Therefore life using it may have interesting chemical weapons or modes of locomotion. A lightweight critter might propel itself with Hydrogen Peroxide, or might fire some sort of nematocyst-like weapon via a peroxide reaction. Concentrated hydrogen peroxide might be used as a venom versus creatures who utilize it in more dilute solutions.
    • Given all this, one could easily imagine a sort of flying jellyfish-like critter, that propels itself with a biological jet, and has trailing stingers to catch prey. It may supplement that diet with a little photosynthesis, generating more peroxide which it then uses as a venom.
  • Hydrogen Peroxide breaks down rapidly when exposed to direct light. Therefore, a creature which relies upon it will either need low-lighting or a non-permeable hide. This conjures up images of crusty cave-dwellers and thick-skinned nocturnal creatures, but it could also work on a planet where a thick atmosphere or dim star keeps the peroxide from breaking down. As mentioned above, the "frozen desert" seems a likely possibility.
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