Re: Earthly origins
Phosphates aren't very water soluble, but that isn't really a problem for basic biochemistry, given that all energetic processes where phosphor is involved ( which are quite important ones ) do not use phosphate, but phosphoric acid.
Which is quite readily soluble in water, and readily formed near, say, the highly acidic environment near an underwater volcano. Which, surprise!, even to this day supports life based on purely anaerobic chemotrophic mechanisms.
People do tend to forget that Early Earth, when life started, was a bit....different... in ecology than nowadays.