Microcosm carbon amendments

Soil represents the most important sink of atmospheric H2. The process is undertaken by H2-oxidizing bacteria (HOB) thriving in soil. The H2 oxidation activity increases with soil organic carbon content, but the incidence of different carbohydrate fractions on the process has received little attention. Here we tested the hypothesis that carbon amendments impact HOB activity and diversity differentially depending on their recalcitrance and their concentration. Carbon source (sucrose, starch, cellulose) and application dose (0, 0.1, 1, 3, 5 %C-equivalent) were manipulated in soil microcosms. Dose-response effects of each carbon sources on H2 oxidation rate were measured weekly for 42 days.