The future of the atmospheric hydrogen soil sink

The National Science Foundation's Division of Atmospheric and Geospace Sciences awarded a Project Grant of $1,215,534 to the University of Arizona under the Geosciences program (CFDA 47.050) beginning September 1, 2025 and concluding August 31, 2028. The award funds research to improve understanding of atmospheric hydrogen removal through microbe-mediated soil uptake, addressing critical uncertainties regarding hydrogen distribution, lifetime, and budgets relevant to the emerging hydrogen energy sector. The project deliverables include continuous in situ measurements of hydrogen fluxes at two field sites with contrasting moisture regimes; development of a one-dimensional diffusion-consumption model and improved hydrogen deposition schemes for global community models; characterization of hydrogen releases from real and simulated hydrogen energy infrastructure using advanced mobile laboratory technology; and quantification of soil interception rates for atmospheric hydrogen plumes. The research generates field measurements, computational models, datasets, and scientific findings that will inform understanding of air quality, radiative balance, and ultraviolet radiation impacts related to hydrogen energy expansion.

The project team will conduct field investigations, computational modeling analyses, and mobile laboratory measurements at natural systems and hydrogen energy installation sites, with research outcomes informing expectations for atmospheric and ecological impacts of hydrogen energy sector growth. The award includes participation from Aerodyne Research Inc., a specialized atmospheric research instrumentation company, as a sub-awardee supporting the measurement and monitoring components. The project incorporates research, education, and mentoring opportunities for young scientists and students, consistent with the Geosciences program's emphasis on workforce development within fundamental Earth system science research.

Abstract

This project aims to improve understanding of the removal of atmospheric hydrogen due to microbe-mediated soil uptake. The central question addressed by the project is whether microbial adaptation to elevated hydrogen is sufficient to mitigate leaks from the hydrogen energy sector. Soil uptake is currently the largest source of uncertainty in the budget, lifetime, and distribution of hydrogen. The project evaluates microbial adaptation to two key forces: moisture regulation of soil hydrogen uptake and micrometeorological regulation of hydrogen plume-surface interactions. The research consists of field measurements in two natural systems differing in moisture and temperature regimes, computational modeling analyses, and measurements using a state-of-the-art mobile laboratory in the vicinity of real hydrogen energy installation sites and from controlled-release experiments. Advancing understanding of the hydrogen soil sink addresses societally important issues of air quality, radiative balance, and UV levels. The project includes research, education, and mentoring opportunities for young scientists and students. The proposal team will leverage their expertise in soil microbial hydrogen uptake, modeling, and novel in situ ecological and mobile lab measurements to generate data and improve models with the following specific project activities planned: (1) generate continuous in situ measurements of hydrogen fluxes under ambient and elevated hydrogen conditions at two sites with contrasting moisture regimes, (2) build a 1-D diffusion-consumption model and improve the hydrogen deposition scheme in a global community model, (3) characterize hydrogen releases from real and simulated hydrogen energy infrastructure using a mobile lab, and (4) quantify the proportion of hydrogen plumes intercepted by soil. Overall, this project will set expectations for the atmospheric and ecological impacts of growth in the hydrogen energy sector while also generating knowledge and tools to project changes to the atmospheric hydrogen budget. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the foundation's intellectual merit and broader impacts review criteria.- subawards are planned for this award.