Alysha Ulrich – Undergraduate Student Profile
Growing up as a Girl Scout and as a member of a rural community, I realized that I wanted to dedicate my career to the preservation of the environment rather quickly. I entered Penn State in the Environmental Resource Management program in the College of Agricultural Sciences, but the concentration on the local ecosystem made me feel like something was missing. I had been eyeing the Earth Science and Policy program in the College of Earth and Mineral Sciences, and I fell in love with my academics once I made the switch. Not only does it capture my passions for the broader environment through the atmospheric sciences, but my major concentration in climate change is teaching me the most modern climate science so that I feel prepared to enter my dream career field in climate policy once I graduate.
The interdisciplinary nature of my degree has encouraged me to pursue internships with the Pennsylvania Game Commission, the City of Pittsburgh’s Sustainability & Resilience Planning Division, organized through the City Semester Pittsburgh program, and the White House Council on Environmental Quality. I’ve also had incredible opportunities to study the natural hazards of climate change in Thailand, pursue atmospheric research with Dr. Michael Mann, and conduct independent research on the impacts of climate misinformation on momentum for climate action.
I will be graduating from Penn State in May 2024 with minors in political science and environmental inquiry as well as a certificate in climate and environmental change. I am so grateful to my mentors in the Department of Geosciences, the broader College of Earth and Mineral Sciences, and the Schreyer Honors College who have helped me find the perfect major.
Clay Wood – Graduate Student Profile
I am a sixth year Ph.D. student from a small town in Southeastern Ohio. I completed a B.S. degree in applied physics in 2016 at Emory University and worked as a research assistant in a fluid mechanics laboratory there for an additional year. My academic background exposed me to fundamental processes, and I learned to apply an analytical eye to complex systems. This led me to research on the complex system we all know and love—the Earth. You may be thinking, "wow, that's a lofty goal!" In all honesty, I thought I should write something that sounds nicer than, "I like the struggle of finding out how things work."
The quick version of my Ph.D. research is that I study properties of fractured rock using laboratory experiments. Much of the shallow subsurface is comprised of discontinuities—cracks, networks of fractures, faults—which can contain water or other fluids. The reason why we care about all of this is because small stress changes from earthquakes or from industrial activities can weaken fractures or reactivate other faults, which can cause earthquakes. We know this from observations of change in fluid flow properties in aquifers and from seismological records.
To understand the underlying physics, my colleagues and I have developed and executed highly controlled laboratory experiments where we use a large hydraulic machine—axial deformation apparatus—to apply stresses and small stress changes, approximating natural conditions, to fractured rock specimens. Additionally, we control the fluid flow through the fracture to measure changes in flow rate as we stress our fractured sample. While this is happening, we monitor, or image, the mechanical changes at the fracture interface using ultrasound—much like using ultrasound in medical applications. Ok, so what does all this mean? The simple answer is that even very small changes in stress applied to a fractured rock temporarily weakens it and larger changes result in weaker fractures. Similar to observations made in the field, fluid flow is transiently enhanced in response to stress changes.
I am very grateful for the support and patience of my advisers, Chris Marone and Parisa Shokouhi, and to my other advisers, Derek Elsworth, Jacques Riviere, and Tieyuan Zhu. Also, I am thankful for the help and friendship from Steve Swavely, Ben Madara, Kerry Ryan, Abby Kenigsberg, Srisharan Shreedharan, Chas Bolton, Tim Witham, Prabhakaran Manogharan, Raphael Affinito, Nolan Roth, Samson Marty, Chun-Yu Ke, and many others. Science is a collaborative effort and I have been enriched by the collegial atmosphere of the department.
Emma Hartke – Doctoral Student Profile
As a child, I always loved science and had a fascination with the natural world. I can clearly recall the times that my friends and I would gather at the playground to look for fossils in the rocks under the swings, when we would wander through the woods and collect animal bones, and other times where we would swim in creeks and pick up all of the turtles, snakes, and fish we could get our hands on. My youth primed me for a career in geosciences, which I ultimately discovered as a career path during my freshman year at the University of Iowa. I obtained my B.S. in geoscience from the University of Iowa in 2020. My undergraduate thesis research was heavily focused on carbon isotope chemostratigraphy of the Silurian Ireviken Event, and I knew I wanted to continue to explore other geochemical problems in graduate school.
I started my M.S. in geoscience at Penn State in fall of 2020 in the Freeman Biogeochemistry Lab. My master’s project is focused on extracting lipid biomarkers—special organic molecules with specific natural sources—from Croatian Holocene paleolake samples to reconstruct landscape changes due to human and climate influence. During the Holocene, the Mediterranean region saw major changes to human and climate activity. Humans began settling into more permanent living structures and began practicing early agriculture. At the same time, the Earth entered a deglaciation state and the Mediterranean experienced several major pulses of aridity associated with ice-rafting events.
The biomarkers I am looking at for this project are n-alkanes and polycyclic aromatic hydrocarbons (PAHs), which can track changes in vegetation distributions and fire activity, respectively. By pairing these biomarker analyses with existing isotope data and archaeological evidence from our study site, we can attempt to explain and distinguish between human and climate interactions across this landscape. This is an exciting study because this will be the first geochemical analysis on one of several “Lost Lakes” in Croatia that have not previously been studied.
Two things I’ve really enjoyed about this project are learning how to operate a suite of new lab instruments and studying a topic so different from my undergraduate project that has both human and geochemical components. I am currently in the final stages of reviewing my data and making interpretations, and my hope is that this data will help resolve questions about the timing and spread of early agricultural practices as well as the impact(s) of human activity and changing climate across a more local landscape. I’m grateful for all that I’ve learned over the last year and a half, in spite of COVID-19, and look forward to continuing towards my Ph.D. here at Penn State in the Freeman Lab.