Ecosystems self-organize to capture atypically large energy in a model of coupled redox transformations

In ecosystems, organisms survive by extracting energy through metabolism, transforming matter and consequently, interacting with others. Yet, we do not understand how much energy ecosystems can capture from their surroundings while obeying the constraints imposed by such metabolic transformations. Here, we systematically study the energy capture efficiency and convergent features of self-organized ecosystems, by means of a new conceptual model which combines ecology with thermodynamically-constrained redox transformations. We find that constraint-satisfying ecosystems show convergent thermodynamic features: namely the set of resource fluxes, network of coupling between transformations, and total energy capture. However, the degree of convergence depends inversely on the potential of the external energy input, with the most convergent ecosystems being nearly energy-limited. Finally, we observe that the dynamics of self-organization produces ecosystems that are extremely efficient at capturing energy, even when compared with machines engineered to maximize energy capture. Our results highlight the role of redox transformations, and the constraints they impose, in organizing ecosystems towards convergent functional non-equilibrium states with atypically large energy capture.