Metabolic evolution and the self-organization of ecosystems

Significance Understanding what drives self-organization in complex systems and how it arises is a major challenge. We addressed this challenge using dominant oceanic photosynthetic and heterotrophic microbes as a model system. Reconstructing the metabolic evolution of this system suggests that its self-organization and self-amplification were coupled and driven by an increasing cellular energy flux. Specifically, the evolution of cells steadily increased their metabolic rate and excretion of organic carbon. We describe how this increases cellular nutrient uptake and thereby ecosystem biomass. The release of organic carbon, in turn, promotes positive feedbacks among species that reinforce this evolutionary drive at the ecosystem level. We propose the evolutionary self-organization of oceanic microbial ecosystems contributed to the oxygenation of Earth.