A key challenge in understanding microbial ecology is addressing the question of how much metabolic heterogeneity exists among organisms that are genetically similar or identical. In other words, given a population of microbial cells, are they all catalyzing the same sets of reactions to make their living? Or does a subset of cells specialize. For example, when presented with a mixture of possible substrates to consume, do all cells use the most advantageous substrate? Or do some cells hedge, utilizing a non-preferred substrate - a strategy that might be advantageous in environments where conditions change frequently?
Through a series of experiments with model organisms, coupled with measurements of individual cells by secondary ion mass spectrometry, we are addressing these questions. The first stage of our investigation involves growing pure cultures in batch and chemostats, measuring, and modeling their growth. The next stage involves examining simple consortia and natural communities, to understand the flow of carbon and nutrients in natural environments.