Five Princeton Students Awarded Walbridge Fund Graduate Award

Joanna M. Foster ’08 for the Princeton Environmental Institute ・ High Meadows Environmental Institute

Five graduate students were selected to receive the Princeton Environmental Institute (PEI) Walbridge Fund Graduate Award in support of their dissertation research at Princeton.

This year’s recipients include: Cara Brook, Victor Charpentier, Jennifer Kasbohm, Anna Trugman, and Yuzhen Yan. Their research addresses important issues in climate change including emergence of zoonotic diseases, dynamics of boreal forest carbon sinks, biomimetic building design, and perturbations in Earth’s climate history.

Initiated in 2009, the PEI Walbridge Fund has provided support to Princeton graduate students pursuing innovative projects in the fields of energy technology, carbon policy, and climate science. The students will use the grants to support their research including fieldwork, travel, conference participation, the purchase of equipment, and costs associated with data analysis and facility use.


Cara Brook

Cara BrookCara Brook has spent nearly half of the last three years of her doctoral program in the Department of Ecology and Evolutionary Biology in Madagascar, where she is studying how climate-driven resource scarcity is impacting the emergence of zoonotic diseases in fruit bats.

“In Madagascar, bats of both Asian and African origins coexist to create a veritable melting pot of viral pathogens,” said Brook. “These bats, which are widely consumed as bush-meat, can serve as reservoirs for several virulent zoonotic diseases, including Ebola, Nipah, and SARS.”

There are multiple factors that influence the spread of infections through bat populations and the likelihood that these will spillover as diseases in humans. Brook is focusing on how climate is affecting food availability in different seasons and how the nutritional status of bats influences transmission between individuals.

“The goal of my dissertation research will be to model the impact of nutritional scarcity on the propensity for seasonal viral shedding and risk of spillover under a series of climate projections,” said Brook.

Brook has already collected pathogen samples from over 800 bats in Madagascar captured throughout every season. The grant from the Walbridge Fund will enable Brook to transport these samples to the laboratory for testing to establish the nutritional status of infected bats.

“Understanding the impacts of climate stressors on resource availability for wildlife—and the impacts which resource scarcities might have on the likelihood of zoonotic emergence—is important for both conservation and public health,” said Brook.


Victor Charpentier

Victor CharpentierVictor Charpentier from the Department of Civil and Environmental Engineering is turning to the mechanics of plant movements for inspiration in creating smart structures that will decrease energy consumption in buildings.

“Buildings in the United States were responsible for 40 percent of the primary energy demand in 2015,” said Charpentier. “But available solutions for shading in building skins – the envelope of the building separating the inside from the outside — have not evolved in essence since Venetian blinds became popular in the 18th century.”

According to Charpentier, in order to allow the maximal flexibility of operation and the most savings in heating, cooling, and lighting, a building skin must be able to react and adapt to variations in environmental conditions and user inputs.

After extensive study of plant movements, including the passive movements of seed dispersal, movements to maximize light capture, defensive movements to protect from a predator, and movements to catch prey in carnivorous plants, Charpentier is ready to begin building prototypes of large-scale mock-ups of biomimetic systems.

Walbridge funds will go towards purchasing materials and equipment for Charpentier’s models of botanic mechanisms.

“Plants are especially useful in this research because they perform movements in low energy states,” said Charpentier. “Therefore the biomimicry of these botanic systems has great potential for translation into adaptive building skins that require little energy and can respond to environmental conditions to boost energy-efficiency in buildings.”


Jennifer Kasbohm

Jennifer KasbohmIn order to better understand how our injection of greenhouse gases into the atmosphere will affect Earth’s climate system in the coming years, Jennifer Kasbohm is looking back into the planet’s past.

Specifically, Kasbohm, a graduate student in the Department of Geosciences, is interested in a period of Earth’s history from about 17–15 million years ago when atmospheric CO2 concentrations spiked dramatically, and the planet experienced a 3C warming. The causes for this warm period known as the Mid-Miocene Climate Optimum or MMCO are uncertain, but massive and sustained volcanic eruptions may have played a role.

To shed light on the connection between volcanism and the spike in global temperatures, Kasbohm traveled to the Columbia Basin in eastern Washington, Oregon, and Idaho, where the dramatic volcanic activity of this period is recorded in vast layers of cooled lava, now basalt rock.

“The emission of CO2 from these eruptions may have played an important role in establishing the elevated global temperatures of the MMCO,” said Kasbohm. “By analyzing samples from this area, I am creating a detailed eruptive chronology for the entire Columbia River Basalt and getting precise estimates of how eruption rates changed throughout its duration.”

Kasbohm will then compare this timeline to other climate records to determine if the elevated temperature and increased CO2 levels occurred coincidentally with, or immediately following eruptions.

The Walbridge funds will support a second trip to the Columbia Basin to collect additional samples for analysis and help cover the cost of lab work.


Anna Trugman

Anna TrugmanBoreal forests currently contain over 30 percent of Earth’s terrestrial carbon. However, the future of these high-latitude forests is uncertain due to increasing air temperature, hotter drought conditions, and changes in fire regime and insect disturbance.

Anna Trugman, a graduate student in the Department of Atmospheric and Oceanic Sciences, is working to elucidate the future resilience of the boreal forest carbon sink by refining predictive models of how these forests will respond to global change.

“My doctoral dissertation focuses on improving our understanding of the mechanistic controls on the boreal forest carbon cycle through an approach that integrates diverse surface and remote sensing measurements with dynamic vegetation models,” said Trugman.

Models are important tools for diagnosing the current state of the carbon cycle and forecasting ecosystem responses to global change. Yet, they often oversimplify important environmental and biological processes. Trugman’s current research focuses on updating an existing dynamic vegetation model with important boreal-specific processes that drive soil carbon accumulation and control forest growth and longevity. She has tested her model in sites throughout Alaska and Canada and is currently working to accurately identify mechanisms behind boreal forest growth and mortality over multiple decades using observations from the Canadian and Alaskan forest inventories.

“This work is crucial to assessing boreal forest resilience to global change and developing forest management strategies in the upcoming century,” said Trugman. “It will enable us to better predict how the boreal ecosystem and the global carbon cycle will respond to global climate change.”

Walbridge funds will enable Trugman to present her research at the Ecological Society of America annual meeting and the American Geophysical Union fall meeting.


Yuzhen Yan

Yuzhen YanYuzhen Yan’s graduate research is focused on finding and analyzing million-year-old ice from Antarctica to better understand Earth’s climate history.

“Finding ice older than 800,000 years is the Holy Grail of the international ice core community,” said Yan, a graduate student in the Department of Geosciences. “We are the only team in the world working in a unique place in Antarctica – Blue Ice Areas — in pursuit of this goal.”

Million-year-old ice is crucial in documenting a dramatic period in the history of Earth’s climate system known as the Mid-Pleistocene Transition. Before this transition, or about 1.2 million years ago, ice ages occurred every 40,000 years. But since about 700,000 years ago, ice ages have occurred every 100,000 years.

In 2015, Yan traveled to East Antarctica with a team from Princeton where they collected 300 meters of ice core samples from the Allan Hills Blue Ice Areas. These areas, known as ablation zones, are like giant conveyor belts that bring deep, old ice towards the surface. Core samples taken from as little as 100 meters down in this area can be as old as ice retrieved from the bottom of the 2-mile thick ice sheet in central Antarctica.

“Ice from Allan Hills Blue Ice Areas provides us with snapshots of atmospheric composition and polar temperature in the Mid-Pleistocene,” said Yan. “My graduate research aims to find the ice older than 800,000 years and analyze its chemical composition to investigate the climate dynamics of the Mid-Pleistocene Transition and to better understand how the climate systems operate on different glacial-interglacial timescales.”

With the support of Walbridge funds, Yan will attend the American Geophysical Union fall meeting and a professional development course in Copenhagen, Denmark.