Basic Information
It has been suggested that life might use hollow, gaseous bubbles rather than gelatinous, watery cells for its biology. An enzyme can function with only a single layer of water molecules attached to it, as it only interacts with nearby water. The enzymes and other large molecules used by life could attach to the surface of a bubble, in the same way they often float on cell membranes, and drift around, catalysing reactions in the vapor of the interior. The lack of a bulk solvent means that water (or other solvent) requirements would be much lower, low enough to survive off humidity in very arid conditions.
They would not have to be simple or fragile lifeforms, as solid polymers could be linked over the surface of the bubble to make tough bags, which may provide enough structure for multicellular life at the cost of less area to absorb water. As there are no issues with ice crystals without bulk water and enzymes can be rehydrated, they might be able to enter hibernation and reactivate quite easily, just by freezing or drying out. The interior, with little water, might have a different biochemistry due to the ability to support molecules that break down when exposed to water, such as the polymers that Silicon-Based Life might be made from.
Apart from vapor bubbles that feed on humidity in a desert, air bubbles in an ocean may be able to capture and encapsulate organic molecules and act in the same way as cells. This might just be a transitional stage during Abiogenesis before the bubbles acquire lipid membranes, increase their stability and inflate with water, but it is perhaps an option that life stays filled with air and evolves into multicellular aggregates. An ecosystem might be made from creatures from thick, simple foams to toughened, sinewy bags sewn into a wide variety of forms. An offshoot might evolve lighter-than-air flight, an Aerostat clothed with muscle and fibrous tissues.
For another concept where life does not use a liquid solvent, look into Plasma-Based Life.
Sources
Game and Story Use
- Perhaps on a Desert Planet there are massive, buoyant aggregates of dry flesh that feed on water from humidity.
- In a vacuum, where substances become volatile more easily, bubble life might work a little more effectively, and sustain itself with a very slow metabolism that only activates when energy is available.