Stanford University
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Alex Hedgpeth
Postdoctoral Scholar, Earth System Science
BioAlexandra Hedgpeth is a biogeochemist whose research explores how soil carbon cycling in peatlands responds to environmental change. Her work focuses on understanding the mechanisms that regulate carbon storage and greenhouse gas production in both tropical and boreal wetlands, with a particular emphasis on the vulnerability of deep, ancient carbon to modern surface inputs and hydrologic shifts.
Through her Ph.D. research at the University of California, Los Angeles, Alex has developed and applied novel isotopic and geochemical approaches—including implementing radiocarbon dating, stable isotope analyses, and high-resolution molecular characterization—to trace the sources and fates of carbon in peat soils. Her fieldwork spans a range of ecosystems, from ombrotrophic bogs in the Arctic to saturated tropical peat domes in Central America. This comparative framework allows her to identify unifying controls on carbon preservation and loss across climate zones.
Alex's research integrates field measurements, laboratory experiments, and synthesis of global datasets. She is a key contributor to multi-institutional efforts to model peatland carbon cycling under climate change scenarios, including DOE- and NSF-supported initiatives. Her work helps clarify the role of peatlands as both long-term carbon sinks and potential sources of atmospheric CO₂ and CH₄ under future disturbance.
In addition to her scientific contributions, Alex is committed to collaborative, interdisciplinary research and has worked closely with partners at national laboratories, the Smithsonian Tropical Research Institute, and international data synthesis networks. She is especially interested in questions with high uncertainty and high relevance to climate feedbacks—such as thresholds in biogeochemical function and the persistence of deep soil carbon under hydrologic change. -
Michelle Hill
Postdoctoral Scholar, Earth and Planetary Sciences
BioMichelle's work addresses a fundamental question in exoplanet habitability: determining the minimum planetary size required to maintain an atmosphere, a critical prerequisite for life as we know it. She found that stagnant lid (no plate tectonics) planets Earth sized and below orbiting in the habitable zone (HZ) of a Sun-like star need to be ≥ 0.8 Earth radii to maintain their atmosphere past 1 billion years. As a Stanford Science Fellow, Michelle will advance her research and expand her planetary habitability models to look at how tectonic regime, initial volatile content, stellar type, tidal locking and tidal heating effect the results of whether a planet smaller than Earth can hold onto it's atmosphere. Her faculty host is Laura Schaefer, Assistant Professor in the department of Earth and Planetary Sciences.
Michelle also detects and refines the masses and orbits of exoplanets using a combination of radial velocity (RV), transit and astrometry. She is currently observing 10 known planet systems that have shown indications of additional planets in orbit in order to detect the long period outer companions. These observations have lead to the discovery of 3 planets so far.
Michelle recently completed her PhD in Earth and planetary sciences at the University of California, Riverside, where she developed research on exoplanet habitability while supported by the NASA FINESST award. She lead a catalog paper on the demographics of all the known planets in HZ of their star where she found evidence of the sub-Saturn valley in the HZ. During this time she was also a member of the TESS-Keck Survey (TKS) team that conducted RV followup of TESS Objects of Interest (TOIs) and she lead the discovery paper of TOI-1386 b and c.
Michelle completed her post bachelor honours in astrophysics at University of Southern Queensland, Australia. Here Michelle worked on the occurrence rates of giant exoplanets in the habitable zone of their star and found that while giant planets are less likely to be found in the habitable zone than terrestrial planets, if each giant planet is host to more than one moon then exomoons could be more numerous than terrestrial planets in the habitable zone of their star. This work has direct implications for the fraction of stars in the galaxy that may host habitable terrestrial worlds.
Prior to this Michelle completed her bachelors in physics at University of New England, Australia where she attended San Francisco State University during her year abroad. Here she contributed to a study of the Kepler habitable zone planets where she found that the distribution of planets within the habitable zone closely mirrored the distribution of all known planets. This discovery had major implications for the opportunities of statistical analysis of this relatively small group of habitable zone planets.
Michelle loves flying! She was a commercial pilot before returning to school to study physics. She currently holds an Australian ATPL with plans to (one day!) convert this to an FAA APT. -
Alexander Honeyman
Postdoctoral Scholar, Earth System Science
BioI work at the intersections of data science, field work, laboratory experimentation, biogeochemistry, and microbial ecology. I was exposed to the issue of wildland fire through 10 years of experience as a volunteer firefighter / EMT in Colorado (fire / rescue / EMS). My current work involves investigating the geochemical character of wildfire smoke by hybridizing analyses of physical samples with various geospatial datasets and atmospheric particle transport models. I love working in environmental systems because they are complex, and offer numerous opportunities to blend the physical and computational sciences.
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Qi Hu
Postdoctoral Scholar, Energy Science and Engineering
BioI am a postdoctoral scholar collaborating with Tapan Mukerji on developing innovative workflows for monitoring subsurface CO2 sequestration. My research primarily involves integrating advanced seismic inversion techniques, such as full-waveform inversion, with rock physics and fluid dynamics to glean insights into subsurface structures and behaviors. Additionally, I am intrigued by the potential of distributed acoustic sensing and machine learning algorithms in various topics related to energy transition.
