Energy is required by all life to fuel growth and activity, including the maintenance of viability in existing biomass. Accordingly, the availability of energy constrains the potential abundance, distribution, and productivity of life. Assessing the relationship between energy flux and the quantity of biomass it sustains offers the potential to understand the biological “carrying capacity” for ecosystems on Earth and beyond, with implications for the “detectability” of life on other worlds.

To help develop this understanding, we quantified the energy-biomass relationship for Earth’s biosphere as a whole and for an environmentally diverse range of its components. Results are interpreted in the context of (i) the apparent range of physiological potential (requirements and capabilities) for energy transduction, as reflected in a database of >10,000 metabolic rate measurements made on >2,900 species; and (ii) the environmental and ecological factors that influence how that physiological potential is expressed at an ecosystem or biosphere level.