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Four Graduate Students Receive PEI Walbridge Fund Awards

Posted by: 
Holly Welles
Publish Date: 
Monday, July 6, 2015 (All day)

Four 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: Rachel Baker, Cleo Chou, Qixing Ji, and Timothy Treuer. Their research addresses important issues in climate change including carbon sinks, tropical forest regeneration, and the production of the greenhouse gas, nitrous oxide.

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 support, travel, conference participation, the purchase of equipment, and costs associated with data analysis and facility use.


Rachel Baker

Rachel BakerRachel Baker’s research topic is “Climate change, employment and migration: What can we learn from historic climate variations?”

A graduate student in the Woodrow Wilson School of Public and International Affairs, Baker has been using statistical methods to investigate how historic deviations in climate change have impacted certain social and economic outcomes, specifically in Sub-Saharan Africa.; She will use the Walbridge funds to supplement her data analysis with field research. “I plan to conduct this research in Malawi, by meeting with local NGOs, community groups and households, to investigate how climate interacts with livelihoods,” said Baker.

The ultimate aim of this research she said is to suggest something about future livelihoods in a climate-changed world. “I will use my quantitative results, enhanced by knowledge gained during field research, to generate models in order to predict how migration may respond to future climate scenarios.”

Baker also said she plans to use the funds to present her results at the Population Association of America conference in 2016.


Cleo Chou

Cleo ChouThrough her dissertation research in the Department of Ecology and Evolutionary Biology, Cleo Chou is researching plant allocation and mechanisms of tropical forest nutrient limitation. “Tropical forests are large carbon sinks, but it is unclear how they will respond to increasing levels of CO2 in the atmosphere. A key uncertainty is the lack of understanding of the mechanisms of how soil nutrients may limit tropical forest growth,” said Chou. “Even as CO2, a main resource for plant growth, increases in the atmosphere, soil’s abundance of other key nutrients like nitrogen, phosphorus and potassium, may not be able to match the CO2 levels, and thus prevent the tropical carbon sink from growing or persisting.”

Consequently for her dissertation, Chou conducted a tropical forest fertilization experiment designed to test for mechanisms of nutrient limitation in terms of plant allocation. She is also building a forest simulation model to scale-up experimental results to determine their significance in the tropical carbon sink;

Chou plans to use the Walbridge funds to cover lab expenses for nutrient analysis of leaf tissue from her experiment.


Qixing Ji

Qixing JiWorking on his dissertation in the Department of Geosciences, Qixing Ji’s research topic is “Nitrous oxide production in marine environments using stable isotope approach.” Nitrous oxide (N2O) is a strong greenhouse gas and powerful ozone depletion agent. The ozone layer helps protect the earth from harmful radiation from the sun. Ji explained, “Today, up to 20% of global emissions originate from the marine environments. Since the Industrial Revolution, human activities have led to increased emissions. Understanding the natural N2O production processes will be critical in predicting responses of the global system to anthropogenic disturbances.” The aim of Ji’s research is to develop a methodology to quantify marine N2O production. Future application of his research will be improving global N2O flux estimate due to human activities and the changing climate.

Ji plans to use the Walbridge funds to support field sample collections in order to generate a comprehensive dataset for his PhD thesis. 


Timothy Treuer

Timothy TreuerTimothy Treuer’s research focuses on the patterns and processes of large-scale tropical forest regeneration in Costa Rica. His proposed research topic is, “Sequestering carbon with orange peels and birds: patterns and processes in the world’s largest tropical forest restoration site.”

“I seek to understand how degraded tropical forests can be restored cheaply and at a large scale not just because doing so is critical for preserving endangered biodiversity, but because tropical land-use change is responsible for a large fraction of global anthropogenic carbon emissions,” said Treuer. “In addition, if properly understood, large-scale restoration of tropical forests on former agricultural land could play a substantial role in a global climate change mitigation agreement.” His research is located in Costa Rica’s Guanacaste Conservation Area—a UNESCO World Heritage Site and the home to many innovative experiments in tropical forest restoration. One chapter of Treuer's dissertation investigates the experimental deposition of orange peels and other agricultural waste products to speed forest regeneration on heavily degraded lands, thereby increasing carbon sequestration.

The Walbridge funds will help Treuer resolve some remaining questions within his broader dissertation project, in particular investigating the role that animals play in recovery of former cattle pastures.