So this is being suggested purely because of phosphorus availability there? How does this compare on that aspect to say the the theory that life arose in alkal

So this is being suggested purely because of phosphorus availability there? How does this compare on that aspect to say the the theory that life arose in alkaline hydrothermal vents? (Note: Alkaline hydrothermal vents are not to be confused with "black smokers", the more famous kind of hydrothermal vent.)