Soils represent habitats with unpredictable conditions for microorganisms, often confronting them with suboptimal conditions for growth. As such, up to 80% of soil microorganisms are assumed to be in a state of non-growth or ‘dormancy’ – a state with low metabolic activity enabling long-term persistence. In many soil systems, microorganisms alter between ‘dormant’ and active states, presumably as a means of survival. It is believed that the state of ‘dormancy’ helps to maintain the extensive biodiversity in soils, with estimates ranging from 1,000- 1,000,000 species per gram of soil. Atmospheric gas oxidation, such as molecular hydrogen, has been proposed as a means to generate energy during periods of carbon limitation. It is believed to be a widespread survival strategy that contributes to bacterial persistence. Using a combination of genomics, transcriptomics, growth-based experiments, enzyme kinetics and molecular analyses, we are exploring this physiology in model organisms and in temperate and desert soils.