Reciprocating thermochemical mediator of pre-biotic polymer decomposition on mineral surfaces

A continuing frustration for origin of life scientists is that abiotic and, by extension, pre-biotic attempts to develop self-sustaining, evolving molecular systems tend to produce more dead-end substances than macromolecular products with the necessary potential for biostructure and function – the so-called 'tar problem'. Nevertheless, primordial life somehow emerged despite that presumed handicap. A resolution of this problem is important in emergence-of-life science because it would provide valuable guidance in choosing subsequent paths of investigation, such as identifying pre-biotic patterns on Mars. To study the problem we set up a simple non-equilibrium flow dynamical model for the coupled temperature and mass dynamics of the decomposition of a polymeric carbohydrate adsorbed on a mineral surface, with incident stochastic thermal fluctuations. Results show that the model system behaves as a reciprocating thermochemical oscillator. The output fluctuation distribution is bimodal, with a right-weighted component that guarantees a bias towards detachment and desorption of monomeric species such as ribose, even while tar is formed concomitantly. This fluctuating thermochemical reciprocator may ensure that non-performing polymers can be fractionated into a refractory carbon reservoir and active monomers which may be reincorporated into better-performing polymers with less vulnerability towards adsorptive tarring.  

Methods
The file reciprocator.ode is an XPPAUT script used to generate Figure 3 and Figure 4 in: 

Ball, R. and Brindley, J. 2024. Reciprocating thermochemical mediator of pre-biotic polymer decomposition on mineral surfaces. J. R. Soc. Interface, accepted manuscript rsif-2024-0492.R2

The file reciprocator.ode.set was generated by running XPPAUT on reciprocator.ode and contains all numerical data and system settings for a particular run.