Abstract
The potential of life's origin in submarine hydrothermal systems has
been evaluated by a number of investigators by conducting high temperature-high
pressure experiments involving organic compounds. In the majority
of these experiments little attention has been paid to the importance
of constraining important parameters, such as the pH and the redox
state of the system. This is particularly revealed in the apparent
difficulties in interpreting experimental data from hydrothermal
organic synthesis and stability studies. However, in those cases
where common mineral assemblages have been used in an attempt to
buffer the pH and redox conditions to geologically and geochemically
realistic values, theoretical and experimental data seem to converge.
The use of mineral buffer assemblages provides a convenient way by
which to constrain the experimental conditions. Studies at high temperatures
and pressure in the laboratory have revealed a number of reactions
that proceed rapidly in hydrothermal fluids, including the Strecker
synthesis of amino acids. In other cases, the verification of postulated
abiotic reaction mechanisms has not been possible, at least for large
molecules such as large fatty acids and hydrocarbons. This includes
the Fischer-Tropsch synthesis reaction. High temperature-high pressure
experimental methods have been developed and used successfully for
a long time in, for example, mineral solubility studies under hydrothermal
conditions. By taking advantage of this experimental experience new
and, at times, unexpected directions can be taken in bioorganic geochemistry,
one being, for instance, primitive two-dimensional information coding.
This article critically reviews some of the organic synthesis and
stability experiments that have been conducted under simulated submarine
hydrothermal conditions. We also discuss some of the theoretical
and practical considerations that apply to hydrothermal laboratory
studies of organic molecules related to the origin of life on Earth
and probably also to the other terrestrial planets. Key Words: Abiotic
organic synthesis-Fischer-Tropsch-type synthesis-Hydrocarbons-HydrothermaI
systems-Magnetite-Olivine-Origin of life-Peridotite-Strecker synthesis.
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