Allometric scaling of maximum population density: a common rule for marine phytoplankton and terrestrial plants

Andrea Belgrano,* Andrew P. Allen, Brian J. Enquist, and James F. Gillooly Department of Biology, University of New Mexico, 167 Castetter Hall, Albuquerque, NM 87131-1091 USA. Department of Ecology and Evolutionary Biology, University of Arizona, BioSciences West, Tucson, AZ 85721 USA. Center for Applied Biodiversity Science, 1919 M. St. NW, Suite 600, Washington, DC 20036 USA. *Correspondence: E-mail: [email protected] Abstract A primary goal of macroecology is to identify principles that apply across varied ecosystems and taxonomic groups. Here we show that the allometric relationship observed between maximum abundance and body size for terrestrial plants can be extended to predict maximum population densities of marine phytoplankton. These results imply that the abundance of primary producers is similarly constrained in terrestrial and marine systems by rates of energy supply as dictated by a common allometric scaling law. They also highlight the existence of general mechanisms linking rates of individual metabolism to emergent properties of ecosystems.