The biogeochemical consequences of dihydrogen (H 2 ) underground storage in porous aquifers are poorly understood. Here, the effects of nutrient limitations on anaerobic H 2 oxidation of an aquifer microbial community in sediment microcosms were determined in order to evaluate possible responses to high H 2 partial pressures. Hydrogen isotope analyses of H 2 yielded isotope depletion in all biotic setups indicating microbial H 2 consumption. Carbon isotope analyses of carbon dioxide (CO 2 ) showed isotope enrichment in all H 2 -supplemented biotic setups indicating H 2 -dependent consumption of CO 2 by methanogens or homoacetogens. Homoacetogenesis was indicated by the detection of acetate and formate. Consumption of CO 2 and H 2 varied along the differently nutrient-amended setups, as did the onset of methane production. Plotting carbon against hydrogen isotope signatures of CH 4 indicated that CH 4 was produced hydrogenotrophically and fermentatively. The putative hydrogenotrophic Methanobacterium sp. was the dominant methanogen. Most abundant phylotypes belonged to typical ferric iron reducers, indicating that besides CO 2 , Fe(III) was an important electron acceptor. In summary, our study provides evidence for the adaptability of subsurface microbial communities under different nutrient-deficient conditions to elevated H 2 partial pressures.