The metabolic physiology of soil microorganisms

This chapter presents an overview of the physiological strategies employed by soil microorganisms. To survive and grow, soil microbes require a carbon source, an energy source, and a means of transferring electrons. The biochemical transformations that soil microbes undertake are governed by the principles of redox reactions and chemical thermodynamics. In addition to phylogenetic diversity, the soil microbial community comprises a large diversity of metabolic strategies, which can be fit into a metabolic classification system. Following this broad introduction, the chapter presents examples of specific soil microorganisms and associated biogeochemical transformations for each metabolic class. The full spectrum of soil microbial metabolism can be synthesized into a simplified conceptual model of multiple interconnected cycles of electrons. This model relates the microscale reactions mediated by soil microorganisms in their search for energy to global biogeochemical cycles.