This is probably off the point of the article but not its title.

I have an interest in astrobiology, but I find the anomalous properties of water [ see here for a recent opinion, without Pollack’s putative gels: ] lacking in both consensus [ibid] and utility.

The process of chemical reactions are decided by the free energy of the total reaction chain. Surface reactions are topologically constrained as volume reactions are not, but that doesn’t add to the basic nature of the process.

Mostly the hopeful observation that the anomalous nature of water appends to a temperature regime (< 50 degC) where many modern cells work gives the game away. We know from phylogenies that the root of all life evolved in a high temperature environment > 70 degC where water is normal. We can see it in the heat shock proteins that likely derives from the UCA lineage.

Moreover the best testable theory of life emergence leading up to the LUCA, vent theory, has the effluents at that temperature. [“The Drive to Life on Wet and Icy Worlds”, Russell et al; Astrobiology] The greigite minerals of alkaline hydrothermal vents that can produce pyruvate from vent H2 and Hadean ocean solute CO2 operates at those temperatures. The Keller et al non-enzymatic metabolic like pathways that produce glucose/pentose from pyruvate operates at those temperatures. And given that purines elaborates on those metabolic pathways, and the vents are perfectly capable to do PCR of RNA with — uniquely — increasing strand lengths, we are done. [Sounds easy, means listing quite a few references, so I omit them for now.]

Finally the chemiosmosis of the LUCA cell metabolism could only evolve at the surface of an alkaline hydrothermal vent, again close to or at those temperatures. The last constraint is nearly, but not quite, conclusive all by itself as far as testing emergence theories goes. That LUCA cell was about as complex as the average prokaryote today. It may be that life never experienced the water anomaly until all of the basic cellular machinery had evolved.

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