Experimental outline: dose-response and reversibility of Phaeodactylum tricornutum metabolism to lithium

This document is a companion protocol to Hall AD, "Why lithium? The Missing Ocean Mineral conjecture: a possible Ediacaran origin for neural lithium function"The document describes an experimental outline for characterising the dose-response and reversibility of metabolic modulation by lithium in the marine diatom Phaeodactylum tricornutum. The experiment is proposed as a test of the MOM conjecture, which holds that lithium originally functioned as an ambient regulatory interrupt in early eukaryotic cells through competition with magnesium at enzyme catalytic sites. A sigmoidal dose-response curve with clean reversibility on lithium dilution would be consistent with this mechanism; a linear response or hysteretic behaviour would not.This is an experimental outline rather than a validated protocol. It sets out the logic, expected observables, and procedural structure.The document is made available under CC BY 4.0 to support independent experimental investigation of the conjecture. The author has no financial interest in the experiment being performed and welcomes contact from any group considering undertaking this work.