Key agreements in the “Law of the River,” which encompasses more than 100 years of regulations, laws, court decisions and more focused on managing the Colorado River, are set to expire next year. First established in 1922 as the Colorado River Compact, the guidelines split water management and allocation among seven states. Now, those states — Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming — are renegotiating the terms of use for the water.
Five years ago, Andrew Nyblade became head of the Penn State Department of Geosciences with a road map based on his vision for the department. In 2019, just like all other road maps of that era, a stack of new tasks quickly piled on top of it.
Nyblade instead found himself embroiled in the fallout of a global pandemic. COVID-19 sidelined in-classroom instruction, lab and field work, research, travel, and conferences: nearly all aspects of the routine activities in the department.
Nyblade, a professor of geosciences with a research focus on geophysics and tectonics in regions such as Africa, Antarctica, and Pennsylvania, said his best laid plans would have to wait. In the immediate, he needed to steer his department through uncharted waters.
“The COVID-19 pandemic really shifted my focus,” said Nyblade, who stepped down June 30. “We were able to accomplish some of the things I set out to do such as improving diversity among our faculty. But my initial task became continuing research and education during the pandemic. My main goal became making sure the department could endure the pandemic.”
Knowing that research was a longtime strength of the department, Nyblade worked to create opportunities for people to stay in touch during the lockdown and sought research alternatives for faculty and students who couldn’t travel. In one case, the department rallied to create a virtual experience for students who were required to participate in field camp to graduate. The department used Google Earth, drone footage, images, and datasets to create a learning experience much like the traditional one.
Nyblade joined Penn State as a National Science Foundation postdoctoral scholar in 1992 before joining the faculty two years later. He was met by a welcoming and accepting mentoring system from senior faculty, so that’s something he wanted to preserve, despite the pandemic challenges.
He made a few key faculty hires that expanded the department’s research breadth while fulfilling his goal of increasing diversity of the faculty because historically geosciences is one the least diverse science fields.
“In retrospect, I think the department is doing extremely well,” said Nyblade, who will remain on the geosciences faculty. “We’ve made a lot of hires and many of them were made during the pandemic with completely remote candidate searches. To me, that’s the overall highlight of my tenure: we hired tremendous junior faculty in the past five years and at the same time improved the diversity of the department.”
Nyblade grew up in Tanzania, the son of missionaries. Later during his research career, he returned to Africa for research and teaching. For a geoscientist, it’s a fascinating place for tectonic research. But it’s also an opportunity for budding geoscientists there to create career opportunities while understanding the Earth beneath them.
Diversity has always been a focus for Nyblade. It’s why, with the help of colleagues in South Africa, he co-founded AfricaArray, an initiative to train and educate Africans in scientific fields vital to natural resource development. The goal was to promote, strengthen and maintain a workforce of highly trained African geoscientists and researchers for Africa. Nyblade plans to publish the results of the twenty-year effort during his sabbatical this year.
Countless studies point to how an increase in diversity leads to a stronger workforce and Nyblade said he believes his profession is leaving a lot of great ideas behind.
“I feel strongly that the people we educate should look like the general population,” Nyblade said. “Everyone is bringing great ideas to the table. If we’re not educating a diverse group of students, and we don’t have a diverse group of faculty, then we’re missing out. People arrive at science and education with different perspectives, and we make the best advances—educational and scientific—if we have a diversity of views. And we’re not where we need to be.”
Welcome to our annual magazine, which is one of the ways we share stories from our past year and reconnect with our alumni and friends. The department is quite healthy, with a steady or slightly growing enrollment. We continue to have about two hundred undergraduate students and roughly eighty graduate students in our various degree programs.
Our department and its programs continue to be highly ranked nationally and internationally. Research expenditures continue to demonstrate excellence, with most of the funding from the National Science Foundation (NSF), the National Aeronautics and Space Agency (NASA), and the Department of Energy (DOE). We are fortunate to be able to share these successes with our alumni and friends, who also support our efforts with generous support to our students and programs. Thank you for your continued support.
In this magazine, we welcome two new faculty members. Nicolas Choquette-Levy, who is joining our department this coming winter, and conducts research focused on using geoscience data to facilitate local governance frameworks for climate adaptation. Eric Kirby joins our department this coming summer as our next department head. Eric’s research focuses on the interplay between climate, erosion, and tectonics during the growth and decay of mountain ranges.
This year, we celebrated the remarkable geochemistry career of Sue Brantley, who retired at the end of 2024. Over her career, she was a tremendous force in both research and teaching, positively impacting many of our students and publishing a numerous highly cited papers. One of our challenges as a department will be replacing the oversized impact Sue had on all of our work and how she elevated our department.
The past summer saw our first implementation of our new four-week field camp structure. The students had a great experience learning GIS and field mapping in Utah, Montana, and Wyoming. Ensuring such authentic, hand-on experiences is one of the areas for which our alumni support is most evident. Support from alumni and friends enhances these types of educational experiences and makes these experiences affordable to our students.
I am only an acting department head, slipping into this role for a year before Eric Kirby arrives. This year, I have gained new perspective on how special our department is. We have outstanding faculty and staff, excellent students, and supportive alumni and friends.
This summer, a group of Penn State professor Susan Brantley’s former graduate students organized a special session at the prestigious Goldschmidt Conference in Chicago to honor their mentor.
Students, collaborators, and colleagues shared cutting-edge research in areas that Brantley spent her career advancing like water-rock interactions and critical zone science.
But her students distilled Brantley’s impact to a simpler message.
Plastered on conference name tags, shirts, and water bottles were stickers that read: Be brave enough to be bad at something new—Be like Sue.
“That’s very congruent with the kinds of things I say, and it really touched me a lot that it is what they remember me for,” said Brantley, Evan Pugh University Professor and Barnes Professor of Geosciences.
Brantley will retire in December after nearly forty years at Penn State, and during her career she was never afraid to try something new.
Ever experimenting in research and leadership roles alike, Brantley rose to the top of the field of geochemistry while blazing a trail for women in a traditionally male-dominated discipline. And she helped shape Penn State for those who followed through leadership roles, like serving as the longtime director of the Earth and Environmental Systems Institute.
“I have a lot of gratitude,” she said. “I couldn’t have done it without a really good place like Penn State. Our college in particular has been a really good place for me. And you know, I changed our college, but our college changed me.”
As a young graduate student at Princeton who had grown fond of her urban surroundings, Brantley wasn’t sure about the idea of moving to central Pennsylvania.
Her adviser, David Crerar, received his doctorate from Penn State, and that connection combined with the University’s lofty reputation in the geosciences were enough to convince her to come for an interview when an assistant professor position opened.
At the time, it was a daunting prospect. Brantley would be the only female faculty member in her department. A senior scientist at another university warned her, “You’ll never make it—they are going to eat you alive.”
“I’ve always kind of been a fighter,” Brantley said. “In college, someone told me that crew was the hardest sport. So, I tried it. If you are going to tell me I can’t do something, I’m going to go do it.”
So, Brantley took the job. And she never left. She said at Penn State she found an environment that allowed her to succeed while becoming a better person, scientist and, most importantly, mentor.
Brantley advised nearly forty doctoral candidates at Penn State, and more than two-thirds of them were women.
“When I went to grad school, we had a small incoming class and about half were women,” she said. “But the number of women who actually went all the way through and got their Ph.D. was much smaller. So I am proud of helping people come into the field and then stick in the field.”
Alexis Navarre-Sitchler, one of those graduate students, is now a professor and department head at the Colorado School of Mines and co-chaired the poster session in honor of Brantley.
Navarre-Sitchler said it wasn’t what Brantley did as a mentor, but what she didn’t do. She never let her students believe something was too hard to figure out.
“Sue taught me to be brave when working in the unknowns of science and that serves as a guidepost for me still today,” Navarre-Sitchler said. “She showed us that it is OK to step into a room, speak loudly and say, ‘This is important. I don’t know the answer, but I have ideas for how we should do it and who can help us.’ And then she got to work.”
Brantley earned her bachelor’s degree in chemistry from Princeton, but after taking a geology course she discovered a passion in addressing questions about rock weathering and soil formation. She continued at Princeton earning her master’s and doctorate in geological and geophysical sciences.
She found that measuring how quickly geochemical reactions happen in the lab did not necessarily translate to how quickly they happen in the field.
“Because I was a chemist, the lab part of it made sense to me, but it was a geoscience program and I really wanted to be able to say, ‘If I measure this in the lab it means it’s going to happen this fast in the field,’ Brantley said. “And we could never make that extrapolation. Really, almost my whole career I’ve been looking at that question—how can you measure the rate of something in the lab and then predict it in a field setting?”
Over time, Brantley realized that in the lab you have one mineral reacting with one solution in a flask, but in the field myriad processes all around are engaging with the reaction.
“It became really clear that it was impossible in some ways to make the extrapolation,” she said. “You couldn’t do it in a flask. You had to look at the whole thing.”
That idea was captured by the emerging field of critical zone science, a cross-disciplinary effort to study the thin outer layer of Earth where rock, soil, water, air, and living organisms interact and shape the planet’s surface.
Brantley became a driving force in developing critical zone research in the United States. The effort led to a $40 million U.S. National Science Foundation-funded program that established Critical Zone Observatories across the world— ncluding at Penn State.
Critical zone science, for example, has helped scientists better understand the complex interactions that influence weathering, the breakdown of rocks at Earth’s surface that acts as a thermostat that helps control the planet’s temperature.
“That was probably the most fun part of my career,” Brantley said. “It was so interactive. It brought so many students in, and you could feel their excitement. Scientists all around the world were excited. It was a wonderful time.”
In 2003, Brantley was appointed as director of the Earth Systems Science Center, now named the college’s Earth and Environmental Systems Institute (EESI), a position formerly held by Eric Barron, Penn State president emeritus and dean emeritus of the College of Earth and Mineral Sciences.
Brantley set out to help researchers address hard and important societal questions related to the sustainability of life on Earth and how to communicate with the public about these issues.
“I always wanted to make scientists’ lives easier to do great science,” Brantley said. “And that’s how I perceived my own job as an administrator. If someone had a problem and they couldn’t get a really cool piece of science done, I viewed my role as finding out what I could do to help them get it done.”
Under Brantley, EESI assembled researchers to address important issues like the environmental and social impacts of the Marcellus Shale gas boom that began in Pennsylvania around 2007.
She began to see her job as director of a small institute within the University through a geology analogy—the wildcatters in the oil and gas industry who seek out high-risk, high-reward drilling opportunities.
“A wildcatter may not have a lot of money compared to the big players, and they are just trying new things,” Brantley said. “They are risk takers, and you know, they might make mistakes. But they also might find a new reservoir. And I thought of EESI as being like that.”
Brantley plans to continue conducting research after her retirement. What she’ll miss, though, is the ability of an administrator to help others solve their problems.
“I think that’s what I miss the most, really, because I can still do science,” she said. “I love thinking about scientific problems. I can still do that, and I can do more of it now because I have more time.”
Brantley said she and her husband, Andy Nyblade, professor and former head of the Department of Geosciences, will maintain their home in State College. But they will do more traveling, including visiting their daughters, who are both early-career geoscientists. Their daughters also happen to live near some of Brantley’s favorite places to ski and paddle on her kayak—two of her passions.
“I feel very happy about retirement, because I’m really happy with the kinds of things that I have already done, and now I have the freedom to do more of the same, but less of the same,” Brantley said. “And I have a lot more time to be outside.”
For the second year, Penn State hosted the International Geobiology Course (IGC), funded by the Agouron Institute and Simons Foundation. Katherine Freeman, Evan Pugh University Professor of Geosciences, and Jennifer Macalady, professor of geosciences, directed the course.
The course explores how microbial life and the Earth have shaped each other and brought together seventeen students pursuing their doctoral degrees.
Students conducted research in central Italy and New York’s Fayetteville Green Lake before traveling to Penn State to analyze their findings.
Central Italy’s Frasassi cave system contains microbial life that endures harsh anoxic conditions, similar to potential life on other planets. Same for Green Lake, which researchers think approximates Earth’s anoxic bodies of water that existed up until about 2.5 billion years ago. Course objectives included exploring how life and Earth processes are linked, by studying microbial ecosystems and biosignatures in modern and ancient thermal springs, tracking biological signatures within ancient sediments, learning testing methods in both the lab and the field, and writing and understanding research papers.
“My colleagues and I were delighted to bring the International Geobiology Course to Penn State,” Freeman said. “This is our second year as hosts of this highly regarded course, which has taught generations of young scholars, many of whom are now scientific leaders in this innovative field. For me, hands down, the best is working with students from all over the world together with our incredibly talented team of instructors.”
Bridget Reheard is one of the three Penn Staters selected as Goldwater Scholars for 2024-25. Goldwater Scholars are selected for their potential as leaders in the fields of natural sciences, mathematics, and engineering. About 5,000 students from across the U.S. applied for one of the 438 awarded scholarships available in 2024.
For the past three years, Reheard, of Lancaster, Pennsylvania, has been researching the implications of brines from Marcellus Shale fracking on stream ecosystems. She is pursuing a double major in geosciences and wildlife and fisheries science. Reheard is both a Schreyer and Millennium Scholar.
“I am studying how potential releases of these hypersaline brines may affect aquatic benthic macroinvertebrate—think insects, crustaceans, etc. that live on the stream bottom—and fish communities in Sproul and Tiadaghton state forests here in Pennsylvania,” Reheard said.
Previously, she conducted research with the Duke University Marine Lab to evaluate changes to genes in the Atlantic killifish in response to the presence of polycyclic aromatic hydrocarbons (PAHs) in the Atlantic Wood Industries Superfund site along the Elizabeth River in Virginia. Reheard explained that changes to certain genes that regulate the metabolism of PAHs can be beneficial since the normal breakdown of these substances can result in DNA adducts and mutations that may reduce survivorship. This past summer, she worked on a project with the NOAA Hollings Marine Laboratry in Charleston, South Carolina, to experiment on the toxicity of different concentrations and mixtures of per- and polyfluoroalkyl substances on larval sheepshead minnow survivorship and gene regulation.
“Being involved in undergraduate research has solidified my interest in aquatic toxicology and genetics and has greatly prepared me for attaining higher education,” Reheard said. “I aim to earn a Ph.D., so having the background and knowledge that I do and having been able to identify a field that matters a lot to me will prove to be pivotal as I search for programs that match my interests and goals.”
Reheard said she faced financial difficulties as she finished high school and entered college, working multiple jobs and tutoring to make ends meet. Earning a Goldwater Scholarship was a special moment, she said.
“I will always be grateful to the Millennium Scholars Program and the Schreyer Honors College for elevating me from poverty conditions to a college education with their financial and academic support,” Reheard said. “I knew that having the opportunity to go to college with all the obstacles I faced early in my life meant that I had to do everything in my power to make the most of it.”
Reheard has served in multiple officer positions of the Penn State chapter of the Wildlife Society. The organization holds a lot of meaning for her, she said, as it provided a way to engage students interested in wildlife careers from a professional and hands-on perspective. She is also part of the American Women in Geosciences and Geosciences Club, the Gamma Sigma Delta Honors Society, and Phi Beta Kappa Honors Society. She said she also enjoys playing soccer with the Centre Soccer Association.
Kayla Irizarry, a doctoral candidate in geosciences, is using her Ford Foundation Predoctoral Fellowship to better understand what controlled diversity in Earth’s earliest complex ecosystems. Her research focuses on the Cambrian period, about 485 million to 541 million years ago, which was a prolific time of change in the history of life known as the “Cambrian Explosion.”
“The Cambrian Explosion was a dramatic transition when simple, soft bodied animals gave way to animals with limbs, heads, hard skeletal parts, and complex sensory organs like eyes,” Irizarry said.
However, in the middle and late Cambrian, species diversity tended to flatten out with high background extinction rates and frequent large extinction events. Irizarry’s research seeks to answer the question: Did fluctuating oxygen conditions control extinction and diversification during this diversity plateau in the latter half of the Cambrian?
“Nearly all animal phyla evolved during the Cambrian Explosion, but in the middle-to-late Cambrian, marine invertebrates experienced high extinction rates hypothesized to have been triggered by persistently low oxygen conditions in the ocean,” Irizarry said.
Irizarry said she wants to look at this question through both a geochemist lens and a paleontologist lens.
“Geochemists will look at the fluctuating oxygen conditions in the ocean, which have been identified by geochemistry, and say it probably affected the animals; and paleontologists will say that the fossil assemblages look like this so maybe this has something to do with the oxygen levels. Not enough researchers are playing both roles,” Irizarry said. “Few studies have combined geochemical and quantitative paleontological data to understand the mechanism by which low oxygen conditions affected marine invertebrate communities.”
The Ford Foundation Predoctoral Fellowship is administered by the National Academies of Sciences, Engineering, and Medicine and provides funding of $27,000 per year for three years.
“I am so thankful for this fellowship,” Irizarry said. “This funding will pay my salary for the next three years and allow me to focus on my research full time.”
Irizarry was one of eighty-seven graduate students awarded a Ford Foundation Predoctoral Fellowship for 2023 and was the only Penn State recipient. She is advised by Mark Patzkowsky, professor of geosciences, and Kimberly Lau, assistant professor of geosciences.
Irizarry earned her bachelor’s degree in earth and environmental science from Brooklyn College and her master’s degree in geosciences from Penn State. She expects to graduate with her doctorate in June 2026.