Dr. Jim Elser is the Regents’ Professor & Parents Association Professor at Arizona State University. His research involves the integrative field of biological stoichiometry, the study of balance of energy and multiple chemical elements in living systems. While this work is primarily ecological in focus and includes studies of both aquatic and terrestrial ecosystems and biota, the approach uses an evolutionary perspective to integrate levels of organization from the molecule and cell to the ecosystem. Specific studies involve observational and experimental studies at various scales, including laboratory cultures, short-term field experiments and sustained whole-ecosystem manipulations. Over the years, field sites have included the Experimental Lakes Area in Ontario, Canada; lakes of the Arctic; lakes, forests, and grasslands of the upper Midwest; desert springs in Mexico’s Chihuahuan Desert; and the surrounding Sonoran Desert. In addition, Dr. Elser collaborates extensively with mathematicians in developing quantitative theoretical approaches to these questions. In more recent work he has extended the work to investigate the connections among C:N:P stoichiometry, growth rate, rRNA physiology and genetics, and ecological dynamics in diverse biota and ecosystems and to evaluate the application of these ideas to tumor dynamics. Currently, he is an active member of the ASU’s NASA-funded Astrobiology project “Follow the Elements” and a co-organizer of ASU’s Sustainable Phosphorus Initiative.