I'm not familar with "the self-ionization of water". My guess is that an energy source like ultra violet light or other radiation "tuned" to the binding energy of water molecules, or cell chemistry, is required to produce the ionization you speak of. Are these ions very short lived..say milliseconds per individual?

We should look for the spectral signatures of O, O2, O+, and O2+ in planetary atmospheres when we get good enough. If life is not present, free oxygen won't hang around very long.

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For those inclined to oppose human meddling with the structure of the universe or the composition and configuration of objects and groups of objects within the universe, consider:
Whether there is a limit to the magnitude of a modulation of chaos below which order remains invariant? Or, is order but a fiction invented by perspectives applied over finite, however large, time intervals?