Research Interests:

My field- and lab-based Geobiology research program utilizes organic and isotope geochemistry, microbiology, and geology to address diverse, fundamental questions about:

Geobiology of extreme environments including the deep subsurface, caves, hypersaline lakes, hydrothermal systems, and ultrabasic systems
Compound-specific isotope organic geochemistry (H, C, N) applied to microbial ecology, biogeochemical cycling in microbe-rich environments, and the sedimentary record of environmental perturbation and climate
Neoproterozoic chemical evolution of the ocean-atmosphere system during extreme isotope excursions
Carbonate sedimentology, stratigraphy, and geochemistry with an emphasis on microbialite preservation and morphology

Education:

2013 Ph.D. Geobiology, California Institute of Technology, Division of Geological and Planetary Science

Thesis: Isotopic proxies for microbial and environmental change: Insights from hydrogen isotopes and the Ediacaran Khufai Formation Advisors: Alex Sessions and John Grotzinger

2008 M.S. Geobiology, California Institute of Technology, Division of Geological and Planetary Science
2007 B.A. summa cum laude, Earth & Planetary Sciences, Environmental Studies, Washington University in St. Louis

Postdoctoral Recognition:

2021 NSF CAREER Award recipient
2021 AT&T Research Fellow, Northwestern University
2020 Fellow, Scialog 2020 – Signatures of Life in the Universe initiative sponsored by Research Corporation for Science Advancement and the Heising-Simons Foundation
2019 Fellow, Canadian Institute for the Advancement of Research (CIFAR) – Earth 4D: Subsurface Science and Exploration Program
2019 Fellow, 2019 US Kavli Frontiers of Science Symposium/li>
2018 Northwestern University Associated Student Government Faculty and Administrator Honor Roll
2017 Packard Fellowship Award

Research Grants:

2021-2026 NSF FRES – Collaborative Research: Evolution of Subsurface Microbe-Rock-Fluid Systems (SMRFS).
2021-2026 NSF CAREER – A Triple-Isotope Approach to Unraveling Subsurface Food Webs
2020-2023 NSF P2C2 – Seasonality of Abrupt Climate Change over Greenland: Direct Tests for the Younger Dryas and 8.2 ka event using Paleolimnology
2018-2021 NASA Exobiology – Biosignature Preservation in Sulfate-Dominated Hypersaline Environments
2017-2022 Packard – Illuminating microbial dark matter using subterranean geomicrobiology
2017-2020 NASA PSTAR – Biologic and Resource Analog Investigations in Low Light Environments (BRAILLE)
2015-2018 NASA Exobiology – Lipid Biomarkers of the Deep Subsurface Biosphere
2015-2017 NASA Astrobiology Institute – Life Underground
2015-2016 Institute for Sustainability and Energy at Northwestern University – Biomarker Records of Arctic Climate Change
2009-2012 National Science Foundation Graduate Research Fellowship

Research Experience:

Characterization of the type, scope, and energetic requirements of the continental deep subsurface biosphere using field and lab measurements of geochemistry, DNA sequencing, cultivation of microbes, and geochemical modeling (J. Amend)
Assessing biological fractionation of hydrogen isotopes by anaerobic bacteria using culturing techniques, compound-specific hydrogen isotope measurements, and modeling of cellular hydrogen flow (A. Sessions)
Characterization of lipid content, D/H, and community composition of a range of hydrothermal mat types to compare proxies and test correlation of D/H with microbial metabolism (A. Sessions, J. Spear)
Characterization of the Neoproterozoic Khufai Formation using sequence stratigraphy, facies analysis, carbon and oxygen isotopes, and sulfur isotopes and concentration to constrain the depositional conditions at the onset of the Shuram excursion and understand changes in Ediacaran biogeochemical cycles(J. Grotzinger, T. Lyons)
Isolation and characterization of novel hyperthermophiles from Yellowstone National Park using hot-spring specific geochemical measurements to inform growth media composition (J. Amend, D. Meyer-Dombard)
Analysis of microbial populations using molecular biological methods in arsenic-rich hydrothermal sediments in Papua New Guinea and acid-sulfate hydrothermal systems in Yellowstone National Park (J. Amend, D. Meyer-Dombard)

Selected Field Experience:

Dec & Aug 2021: Sample Collection at Mammoth Cave National Park for NCKRI funded seed project
Sept 2018 & 2019: Sample collection and geochemical characterization of hypersaline lakes in British Columbia with Alex Pontefract and Chris Carr.
Aug-Sept 2018: Sample collection at Lava Beds National Monument in Lava Caves for the BRAILLE project
Oct-Feb 2013-2014: Subsurface sample collecting trips to the SURF laboratory in the former Homestake Mine for initial fields site characterization and geobiological research.
Jan-Mar 2009-2012: Four to seven week field seasons in Oman characterizing the Neoproterozoic Khufai Formation including: measuring stratigraphic sections, collecting samples for chemostratigraphy, and analyzing stratigraphic relationships.
Mar 2011: Carbonate Stratigraphy field course, Permian Reef in the Guadalupe Mountains (J. Grotzinger)
Mar 2009: Modern Carbonate Sedimentology field course, Lee Stocking Island, Bahamas (J. Grotzinger)
July 2008, 2009: Sample collection and geochemical characterization of hydrothermal microbial mats from Yellowstone National Park, USA (A. Sessions, John Spear)
July 2007: Geochemical and microbial sampling of shallow submarine hydrothermal vents in the Aeolian Islands, Italy (J. Amend, D. Meyer-Dombard, R. Summons, E. Shock)
June-July 2006: Six weeks in Montana and Wyoming as part of YBRA geology field camp
June-July 1999-2006: Field cartography assistant and geochemistry technician for Group Exploring Organic Processes in Geochemistry (GEOPIG), School of Earth and Space Exploration, Arizona State University (E. Shock)
June 2004, 2005: Geologic Mapping Field Assistant, New Mexico State Mapping Project New Mexico Bureau of Geology and Mineral Resources (G. Osburn, S. Kelley)