Sessina Dani ’23


Ecology and Evolutionary Biology

Project Title

What Controls the Biodiversity and Function of Cryptogam Microbiomes?

I investigated the biotic and abiotic factors affecting cryptogam biodiversity and function. We studied their roles in biological nitrogen availability by measuring different aspects of cryptogam function, like biological nitrogen fixation, production of greenhouse gas nitrous oxide, and component bacteria communities. My co-interns and I collected field samples across latitudes and altitudes in Québec, Canada, and in North Carolina. I had the opportunity to familiarize myself with various species of mosses, lichens, and liverwort in the field and learned about their biome-specific, ecosystem-specific, and microenvironment-specific differences. We visited and met researchers and colleagues at the Université de Sherbrooke, Highlands Biological Station, and The Watershed Institute. Back in the lab, we performed chemical and biological analyses, which we then processed into quantitative measurements of cryptogam function. I enjoyed many firsts, like short-term and long-term project planning and implementation, a glimpse into highly interdisciplinary environmental research, and I developed important critical thinking and problem-solving skills. I also gained exposure to environmental research and increased my knowledge of botany and geochemistry. Now, I notice cryptogams everywhere, noting all the same patterns we learned about and observed this summer.

* This internship is connected to the HMEI Biodiversity Grand Challenges project, “What Controls the Biodiversity and Function of Cryptogram Microbiomes.”

Internship Year


Project Category

Climate and Environmental Science


Zhang Lab, Department of Geosciences, Princeton University - Highlands, North Carolina; Princeton, New Jersey; Sherbrooke, Québec, Canada


Xinning Zhang, Assistant Professor of Geosciences and the High Meadows Environmental Institute, Romain Darnajoux, Associate Research Scholar, Geosciences