ELSER, JJ; Arizona State University: Biological stoichiometry from genes to ecosystems: ideas, plans, and realities

Biological stoichiometry is the study of the balance of energy and multiple chemical elements in living systems. This approach grows out of work in the arena of aquatic ecosystem science but in our ongoing IRCEB project we are extending these ideas into diverse areas of organismal and evolutionary biology and into new habitats, including deserts, forests, and grasslands. In this talk I describe the main ideas we are testing in our “Genes to Ecosystems” (GTE) project, in particular the Growth Rate Hypothesis, which states that variation among living things in the C:N:P stoichiometry of their biomass is a function of growth rate due to the requirement for increased allocation to P-rich ribosomal RNA during rapid growth. In addition, specific patterns in the structure of the genes coding for ribosomal RNA (i.e., in the rDNA) are also a part of the GRH. Since C:N:P stoichiometry has major ramifications for ecological processes such as trophic interactions, nutrient cycling, and organic matter sequestration, this chain of interactions has the potential to mechanistically link the fundamental cellular-genetic processes of growth to organismal physiology to ecosystem dynamics. In the talks that follow you will see various results from the GTE project supporting the overall set of ideas associated with the Growth Rate Hypothesis but also pointing us to new directions in achieving a stoichiometric synthesis of the living world.