Incorporating chemical stressors and microbial stress responses into biogeochemical understanding
Microbes drive many critical bioegeochemical processes in ecosystems, and collectively microbial communities possess diverse metabolic capabilities and vary greatly in their resource requirements. Microbial ecology has largely focused on how resource supply and supply ratios drive the relative dominance and rates of metabolic pathways. Yet microbes, like macroorganisms, are subjected to a variety of physical and chemical stressors that may drive microbially mediated processes away from strict thermodynamic or stoichiometric optima. The interaction between microorganisms and chemical subsidies or stresses may be sufficient to drive changes in ecosystem processes. We suggest this is particularly likely for novel stressors or stressor combinations acting on microbial function that are narrowly distributed phylogentically or rare.
We will explore our current understanding of microbial stress/subsidy relationships and the challenges that arise in applying information from pure culture studies to complex natural microbial communities. We will report the results of a literature synthesis effort to compile cases in which chemical contaminant exposure has led to changes to in microbial community composition, microbially mediateted biogeochemical function or both and the frequency with which these studies are able to show an impact at the ecosystem scale. We suggest that a new focus on microbial ecotoxicology integrated ecosystems may prove a fruitful venue for relating microbial community assembly to cummulative microbial function.