July 31, 2025 by Teamrat A Ghezzehei

Yulissa Defends PhD Dissertation

We are thrilled to announce that Yulissa Perez-Rojas successfully defended her PhD dissertation on July 31, 2025, completing her doctorate in Environmental Systems. This outstanding achievement marks the culmination of years of rigorous research and intellectual pursuit.

Dr. Perez-Rojas’s dissertation, titled “The Scale Integration Challenge: How Moisture Variability and Osmotic Stress Create Systematic Biases from Laboratory to Continental Carbon Predictions,” addresses one of the most pressing challenges in Earth system science: scaling carbon cycle processes from laboratory measurements to continental-scale predictions.

Her groundbreaking research investigates how moisture variability and osmotic stress—factors often overlooked or simplified in large-scale models—create systematic biases when scaling up from controlled laboratory experiments to regional and continental carbon predictions. This work has profound implications for improving Earth system models and our ability to predict carbon cycle dynamics under changing climate conditions.

Through innovative experimental designs, data analysis, and modeling approaches, Dr. Perez-Rojas has revealed critical mechanisms by which small-scale environmental heterogeneity affects large-scale carbon predictions. Her findings demonstrate that accounting for moisture variability and osmotic stress is essential for reducing uncertainty in carbon cycle models and improving our predictions of ecosystem responses to climate change.

Dr. Perez-Rojas’s research contributes significantly to the broader scientific effort to bridge the gap between process-level understanding and Earth system-scale predictions, advancing both fundamental soil science and applied climate modeling.

Congratulations to Dr. Yulissa Perez-Rojas on her exceptional achievement! We are immensely proud of her accomplishments and excited to see the continued impact of her research in the field of environmental systems science.