Lucy Huelskamp ’24



Project Title

Molecular Biological Investigation of the Marine Nitrogen Cycle

Presentation Link

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I researched genes involved in denitrification, nitrogen fixation, nitrate reduction, and nitrite oxidation — nosZ, nifH, nxrB, and narG, respectively — as part of the Ward Lab, which studies nitrogen cycling in oxygen minimum zones (OMZs). I contributed to a project studying nitrogen fixation in OMZs by working to understand the diversity and activity of the microbes involved. I amplified nifH, a gene encoding dinitrogenase reductase, by polymerase chain reaction (PCR) using barcoded primer pairs from DNA and RNA extracted from the eastern tropical North and South Pacific OMZs’ water columns. After amplification, I purified the PCR products using a gel extraction protocol and quantified the clean products. Equal quantities of these products will be pooled and sequenced at the Genomics Core Facility. The resulting sequence data is expected to reveal the identities and relative abundances of the dominant nitrogen-fixing microbes present at different depths in the OMZs’ water columns. This can be correlated with rate data to offer insights into the diversity and activity of prokaryotic nitrogen fixers present in these OMZs. Through this project, I gained valuable microbiology research experience through and I enjoyed learning about the adaptations nitrite oxidizing bacteria possess that allow them to operate in OMZs.

Internship Year


Project Category

Climate and Environmental Science


The Ward Lab, Department of Geosciences, Princeton University - Princeton, New Jersey


Bess Ward, William J. Sinclair Professor of Geosciences and the High Meadows Environmental Institute; Samantha Fortin, Postdoctoral Research Associate, Geosciences; Amal Jayakumar, Senior Professional Specialist, Geosciences