I am a microbiologist that is interested in developing a better understanding of microbial physiology: how microbes harvest energy and materials from their environment to reproduce. In the course of acquiring energy and materials, microbes catalyze many chemical transformations. Since microbes are among the most abundant forms of biomass on the planet, these chemical transformations have global significance. Thus, microbial physiology is intimately tied to biogeochemistry. Some microbes I have worked on include methanotrophic bacteria that consume the flammable greenhouse gas methane and filamentous cyanobacteria that harvest light as an energy source to fix carbon dioxide into biomass plus converting nitrogen gas to ammonium all while producing oxygen gas. More recently, I have focused on microbes that interact with group VIa elements: primarily sulfur, but also selenium, tellurium, and polonium. My lab currently focuses on anaerobic phototrophic bacteria and how they extract electrons from reduced forms of sulfur: sulfide, thiosulfate, and elemental sulfur. My research uses a wide variety of techniques including both molecular and classical microbiology, various "-omics", bioinformatics, and analytical chemistry. This research has been generously supported by the National Science Foundation, Department of Energy, German Academic Exchange Service (DAAD), Delaware EPSCoR, and the University of Delaware Research Foundation.