Thermal Gradients
Vent-driven temperature differences power endergonic chemistry
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Redox Chemistry
Mineral-surface electron transfer (FeS, pyrite catalysis)
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UV Radiation
Photolysis & photochemistry near the surface (Beer-Lambert attenuation)
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Lightning
Stochastic electrical discharges — Miller-Urey energy source
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Energy by Depth
Thermal
Redox
UV
Lightning