The IRCEB program seeks to promote research that integrates across multiple levels of biological organization and across diverse types and habitats of organisms. Such work should articulate general principles that can begin to re-unify the increasingly fragmented wealth of biological knowledge that this century has generated. HOST-PATHOGEN BIOLOGY AND THE GLOBAL DECLINE OF AMPHIBIANS This NSF funded project is aimed at understanding the role of pathogens in causing the decline of amphibians. The principal question being asked is: Why are pathogens causing some amphibian populations to decline, even to extinction? Specific questions include: How do pathogens influence host pathogen dynamics? Have recent environmental changes altered amphibian-pathogen interactions? BIOLOGICAL STOICHIOMETRY FROM GENES TO ECOSYSTEMS Our project involves a diverse team of researchers that includes a physiologist, a microbial ecologist, theoretical biologists, evolutionary biologists, limnologists, and a terrestrial ecosystem ecologist. It involves an explicit, conceptually organized, integration from genes to ecosystems, from microbes to metazoans, and from lakes to deserts. We propose to use the framework of "biological stoichiometry" to assess how the fundamental chemical balance required for growth links the genetics and physiology of organisms to ecosystem dynamics.