Alexis Templeton

How fast do hydrogen consuming microbial organisms grow in geological hydrogen systems that reside within the temperature limits of life (e.g. <121oC), and what is their impact on the steady-state abundance of hydrogen in the subsurface? There is currently a lack of data regarding the abundance of microbial life in geological hydrogen source and reservoir rocks, and how fast these organisms grow, which has significantly implications for calculating whether hydrogen can accumulate or will be substantially consumed. We will share new methods and spectroscopic tools we are developing that can be used to quantify the rates of microbial activity in hydrogen-bearing rocks and fluids. We then apply these tools to rocks and fluids obtained from partially-serpentinized peridotite aquifers in Oman, as well as generate data from experiments designed to more generally apply to hydrogen systems. The new data being produced shows many orders of magnitude variability in microbial hydrogen-dependent activity rates depending upon the mineralogy, salinity, pH and abundance of oxidants that can then be better integrated into emerging models of natural and stimulated hydrogen systems.

Co-auteurs : Srishti Kashyap, Tristan Caro, Carson Cucarola, Eric Ellison