Bridging microbial and theoretical ecology to investigate cooperative strategies in bacteria

• Jill L. S. Murray

Abstract
Microbiologists have recently become equipped to identify the taxonomy of bacteria in situ, understand phylogenetic relationships among groups, and assay gene expression in individuals, a development that parallels the explosion of natural-history studies by general ecologists a century ago. One of the most exciting recent discoveries is that bacteria engage in extensive chemical signaling and density-dependent behavior, some of which appears to involve cooperative adaptive strategies. Paralleling early ecologists who studied cooperation, microbiologists have not yet developed rigorous theory to test these ideas. Because theoretical and microbial ecology have developed with little interdisciplinary crossover, microbiologists have not capitalized on the existing framework that is now available to investigate cooperation in higher organisms. The gap between empirical microbiology and quantitative theoretical ecology is a common theme that must be addressed as microbial natural history unfolds. I aim to work at the interface of the two fields; my goal is to learn if and how cooperative strategies play a role in the spatial distributions of bacteria in nature. This work will involve predictive numerical and simulation modeling of microbial foraging strategies and their resulting spatial patterns, developed to enable discrimination amongst modes of selective pressure in future experimental tests. A mechanistic understanding of adaptive strategies in bacteria is essential to the understanding microbial food webs, bacterial infections, biogeochemical cycles, and the bioremediation of contaminated habitats. The scaling of ecological theory to microscopic proportions will also benefit general ecology, as long-standing questions can be tested in microbial systems that can be modeled almost perfectly and tested over relatively vast spatial and temporal scales given the sizes and generation times of bacteria.