Quantifying the energetics of microbial growth*

Energetics is central to microbial life. The strategies by which microbes harbor and spend energy comprise an essential link between the geochemical and biological makeup in an ecosystem. A quantitative understanding of these strategies and their underlying mechanisms can provide useful insight into the microbial component in the global cycling of carbon, nitrogen, sulfur, and other elements. We study the growth of various environmentally relevant microbes using calorimetry, which measures the heat dissipation. We combine this approach with other biological and geochemical methods to dissect energy flow in various types of microbial metabolism.