I earned a Bachelor of Science in Environmental Geosciences from the University of Notre Dame in May 2012. My undergraduate research experiences exposed me to the intersection of microbiology and environmental remediation, as well as pioneering techniques for separating spent nuclear fuel. I had the opportunity to participate in two internships at Pacific Northwest National Laboratory looking at uranium contamination in the vadose zone as well as microbiological responses to remediation amendments. To further my knowledge in microbiological-geological interactions, I earned a Ph.D. in geomicrobiology from the University of Colorado at Boulder under Dr. Alexis Templeton. The work focused on advanced spectroscopic techniques to understand Fe redox water/rock reactions while also looked at unique carbon and hydrogen isotope values produced by methanogens in extreme environments. Overall, I enjoy learning new, multidisciplinary analytical techniques and focusing on problems that have a clear application. Outside of the lab, I enjoy rock climbing, trail running and reading.
My work in the Borch lab will focus on analyzing the efficacy of typical treatments practices for slowing the spread of citrus greening in Florida. I will work with a multi-disciplinary team to determine the best insecticide and land management practices to cultivate a resilient citrus industry. More to come soon!
Low temperature water/rock reactions
My PhD research focused on characterizing low-temperature water/rock reactions that lead to hydrogen production. Hydrogen is a strong electron donor that, along with electron acceptors such as CO2 or SO42-, can sustain microbial life. I performed experimental and analytical work with partially serpentinized rocks from the Samail ophiolite in Oman to understand the key reactive Fe-bearing minerals behind H2 production. This multi-disciplinary work exposed me to a variety of analytical techniques to tackle complex problems spanning geochemistry to water chemistry to microbiology.
Advanced spectroscopic techniques
I have experience generating hyperspectral micro-Raman maps to generate high quality maps of mineralogical samples. This high level of detail gives insight into low-temperature water/rock reactions involving iron oxidation. Additionally, I have worked at the Stanford Synchrotron Radiation Lightsource (SSRL) to generate Fe K-edge micro x-ray absorption near edge spectra (µXANES) with members of the Templeton lab at the University of Colorado at Boulder. Along with Eric Ellison and Dr. Lisa Mayhew, we developed a technique to analyze the pre-edge region of the Fe K-edge that allows us to constrain the Fe(II)/(III) ratio in minerals. This gives us more complete information about past water/rock reactions and the future redox potential of mineral phases.
Biological methane isotopes
I have isolated methanogens from subsurface pH 10.5 fluids in Oman and grown them over a range of alkaline pHs (8-10.5), then measured their carbon and hydrogen isotope values. These methanogens that grow at high pHs in carbon-limited environments have 13CCH4 values greater than -40‰, which expands the range of known archaeal 13CCH4 values. This calls into question past interpretations of abiotic methane from natural environments based on 13CCH4 values.
For more details about the research conducted in the Borch group please click here.
Miller HM, Mayhew LE, Ellison ET, Kelemen P, Kubo M, Templeton AS (2017) Low temperature hydrogen production during experimental hydration of partially serpentinized dunite Geochim. Cosmochim. Acta 209, 161-183
Rempfert KR, Miller HM, Bompard N, Nothaft D, Matter JM, Kelemen P, Fierer N, Templeton AS (2017) Geological and geochemical controls on subsurface microbial life in the Samail ophiolite, Oman. Frontiers in microbiology. Volume B, 56.
Miller HM, Mayhew LE, Ellison ET, Kelemen P, Kubo M, Templeton AS (2017) Reply to “Methane origin in the Samail ophiolite: Comment on “Modern water/rock reactions in Oman hyperalkaline peridotite aquifers and implications for microbial habitability”” [Geochim. Cosmochim. Acta 179 (2016) 217–241]
Miller HM, Mayhew LE, Ellison ET, Kelemen P, Kubo M, Templeton AS (2016) Modern water/rock reactions in Oman hyperalkaline peridotite aquifers and implications for microbial habitability. Geochim. Cosmochim. Acta 179, 217–241
Wang S, Alekseev EV, Diwu J, Miller HM, Oliver AG, Liu G, Depmeier W, Albrecht-Schmitt, TE (2011), Functionalization of Borate Networks by the Incorporation of Fluoride: Syntheses, Crystal Structures, and Nonlinear Optical Properties of Novel Actinide Fluoroborates. ChemInform, 42
Wang S, Alekseev EV, Diwu J, Miller HM, Depmeier W, Albrecht-Schmitt, TE (2011), Boronic Acid Flux Synthesis and Crystal Growth of Uranium and Neptunium Boronates and Borates: A Low-Temperature Route to the First Neptunium(V) Borate.ChemInform, 42
For more publications in the Borch group please click here.
Name of collaborator, Institution, Link to their website.
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