  Autocatalysis is thought to have played an important role in the earliest
stages of the origin of life. An autocatalytic cycle (AC) is a set of reactions
that results in stoichiometric increase in its constituent chemicals. When the
reactions of multiple interacting ACs are active in a region of space, they can
have interactions analogous to those between species in biological ecosystems.
Prior studies of autocatalytic chemical ecosystems (ACEs) have suggested
avenues for accumulating complexity, such as ecological succession, as well as
obstacles such as competitive exclusion. We extend this ecological framework to
investigate the effects of surface adsorption, desorption, and diffusion on ACE
ecology. Simulating ACEs as particle-based stochastic reaction-diffusion
systems in spatial environments-including open, two-dimensional
reaction-diffusion systems and adsorptive mineral surfaces-we demonstrate that
spatial structure can enhance ACE diversity by i) permitting otherwise mutually
exclusive ACs to coexist and ii) subjecting new AC traits to selection.
