Thermodynamic and metabolic effects on the scaling of production and population energy use

S. K. Morgan Ernest*, Brian J. Enquist, James H. Brown, Eric L. Charnov, James F. Gillooly, Van M. Savage, Ethan P. White, Felisa A. Smith, Elizabeth A. Hadly, John P. Haskell, S. Kathleen Lyons, Brian A. Maurer, Karl J. Niklas and Bruce Tiffney Department of Biology, University of New Mexico, Albuquerque, NM, USA Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA Santa Fe Institute, Santa Fe, NM, USA Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA Department of Biological Sciences, Stanford University, Stanford, CA, USA Department of Rangeland Resources, Utah State University, Logan, UT, USA Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI, USA Department of Geography, Michigan State University, East Lansing, MI, USA Department of Plant Biology, Cornell University, Ithaca, NY, USA Department of Geological Sciences, University of California, Santa Barbara, CA, USA *Correspondence: E-mail: [email protected] Abstract Ecosystem properties result in part from the characteristics of individual organisms. How these individual traits scale to impact ecosystem-level processes is currently unclear. Because metabolism is a fundamental process underlying many individualand population-level variables, it provides a mechanism for linking individual characteristics with large-scale processes. Here we use metabolism and ecosystem thermodynamics to scale from physiology to individual biomass production and population-level energy use. Temperature-corrected rates of individual-level biomass production show the same body-size dependence across a wide range of aerobic eukaryotes, from unicellular organisms to mammals and vascular plants. Population-level energy use for both mammals and plants are strongly influenced by both metabolism and thermodynamic constraints on energy exchange between trophic levels. Our results show that because metabolism is a fundamental trait of organisms, it not only provides a link between individualand ecosystem-level processes, but can also highlight other important factors constraining ecological structure and dynamics.