[Back to Meeting 2003]

NSF Integrated Research Challenge in Environmental Biology (IRCEB): Biological Stoichiometry from Genes to Ecosystems

Symposium organized by
Jon Harrison

The National Science Foundation has made a significant commitment to funding collaborative proposals aimed at promoting research that integrates across multiple levels of biological organization and across diverse types and habitats of organisms (Integrative Research in Environmental Biology, IRCEB and Frontiers in Integrative Biological Research, FIBR).  One goal of these programs is to articulate general principles that can begin to re-unify the increasingly fragmented wealth of biological knowledge that this century has generated.  This symposium will provide a summary of the four-year results of one of the two NSF IRCEB proposals funded in the first year of the program, "Biological Stoichiometry from Genes to Ecosystems".  


Biological stoichiometry uses fundamental principles of chemical balance to link genetics, organismal physiology, community structure, and ecosystem processes.  The organizing foci of this research is a hypothesis that fast- and slow-growing organisms differ in their C:N:P stoichiometry, because fast-growing organisms require high concentrations of P-rich ribosomal RNA.  The research addressed by the Biological Stoichiometry IRCEB group includes an Organismal Component, which has a goal of rigorously testing the relationship between growth rate, organismal P- and RNA-content in a wide array of terrestrial and aquatic invertebrates, and also includes studies of the physiological and behavioral responses of organisms to variation in dietary C:N:P.  A second Evolution Component of the IRCEB grant considers the links between stoichiometry and growth in an evolutionary context, using terrestrial (Drosophila) and aquatic (Daphnia) model systems for comparative, phylogenetic studies as well as artificial selection experiments.  This component also is examining the genetic mechanisms responsible for producing variation in ribosomal RNA, specifically examining links between growth rate and promotor-binding intergenic spacer lengths known to regulate ribosomal RNA production.  A third Ecology Component examines links between organismal C:N:P and community/ecosystem processes by testing for links between C:N:P of the primary producers and consumers across gradients in N and P availability in lakes, grasslands, deserts, and forests.  Data to date suggest that environments with high P availability support rapidly growing, high P-species, while environments with poor P availability are dominated by slower-growing, low-P species.  Both the Ecology and Evolution components also have strong modeling components, which utilize both analytical and computational approaches to examine the theoretical significance of biological stoichiometry.  Further information on this IRCEB program is available at http://lifesciences.asu.edu/irceb/stoichiometry/.


Symposium Program:

8:00  Scott Collins, National Science Foundation.  Overview of the NSF IRCEB and FIBR programs.

8:20.  James Elser, Arizona State University: Overview of biological stoichiometry from genes to ecosystems

9:00.  James Cotner, Univ. of Minnesota: Links between growth rates, stoichiometry, and RNA of bacteria.

9:40.  Jon Harrison and H. Arthur Woods, Arizona State University and the Univ. of Texas: The causes and significance of C:N:P variation in insects.

10:20.  Coffee break

10:40  Larry Weider, Univ. of Oklahoma: rDNA intergenic spacer sequence variation and its significance for influencing growth and/or developmental rates of organisms.

11:20 Teri Markow, Univ. of Arizona:  The evolution of growth rate variation in drosphilids.

12:00 Lunch break

1:20.  John Schade and Sarah Hobbe, Univ. of Minnesota: Biological stoichiometry of terrestrial ecosystems.

2:00  Robert Sterner, Univ. of Minnesota: Biological stoichiometry of aquatic ecosystems.

2:40 Coffee break

3:00.  William Fagan, University of Maryland: Theoretical consequences of links between growth rate and body stoichiometry for community structure.

3:40.  Yang Kuang, Arizona State University: Stoichiometry and biodiversity: mathematical models, analysis and simulation.

4:20. Panel Discussion: How should multi-laboratory research programs for integrative biological research be designed and organized?