Rapid Consumption of Dihydrogen Injected into a Shallow Aquifer by Ecophysiologically Different Microbes
Nina Keller, Klas Lüders, Götz Hornbruch, Susann Birnstengel, Carsten Vogt, Markus A. Ebert, René Kallies, Andreas Dahmke, Hans H. Richnow
Abstract
High Resolution Image Download MS PowerPoint Slide The envisaged future dihydrogen (H 2 ) economy requires a H 2 gas grid as well as large deep underground stores. However, the consequences of an unintended spread of H 2 through leaky pipes, wells, or subterranean gas migrations on groundwater resources and their ecosystems are poorly understood. Therefore, we emulated a short-term leakage incident by injecting gaseous H 2 into a shallow aquifer at the TestUM test site and monitored the subsequent biogeochemical processes in the groundwater system. At elevated H 2 concentrations, an increase in acetate concentrations and a decrease in microbial α-diversity with a concomitant change in microbial β-diversity were observed. Additionally, microbial H 2 oxidation was indicated by temporally higher abundances of taxa known for aerobic or anaerobic H 2 oxidation. After H 2 concentrations diminished below the detection limit, α- and β-diversity approached baseline values. In summary, the emulated H 2 leakage resulted in a temporally limited change of the groundwater microbiome and associated geochemical conditions due to the intermediate growth of H 2 consumers. The results confirm the general assumption that H 2, being an excellent energy and electron source for many microorganisms, is quickly microbiologically consumed in the environment after a leakage.