Zachary Sahin ’23



Project Title

The Impact of Large Mammalian Herbivores on Small Invertebrates: A Literature Review

Presentation Link

View Zachary's Presentation

Certificate(s): American Studies, Near Eastern Studies

High productivity and slow circulation in the Eastern Tropical North Pacific (ETNP) results in one of the world’s largest oxygen deficient zones (ODZ). Organisms there rely on nitrate for respiration via water column denitrification (WCD). Reconstructing how rates of WCD in ODZs have changed since the last glacial maximum has important implications for understanding past changes in ocean circulation and abyssal carbon storage. During WCD, the expression of a large isotope effect elevates the 15N nitrogen to 14N nitrogen ratio of nitrate supplied for primary productivity above ODZs. This allows the Sigman Lab to make inferences about the extent of WCD based on the 15N/14N of fossil-bound organic matter deposited on the ocean floor. I prepared fossil foraminifera samples from a ETNP core site to be analyzed for a new nitrogen-isotope record covering the last glacial-interglacial transition. The hands-on work strengthened my skills in microscopy. In our weekly meetings, my mentor improved my understanding of the fields of paleoclimatology and oceanography through paper readings and discussions, and of the research process in general. I look forward to exploring these fields further and drawing on this experience for my own studies and independent research.

* This internship is connected to the HMEI Water and the Environment Challenge project, “Causes and Consequences of Water-Mediated Pattern Formation in Arid African Rangelands.”

Internship Year


Project Category

Biodiversity and Conservation


Pringle Lab, Department of Ecology and Evolutionary Biology, Princeton University


Robert Pringle, Professor of Ecology and Evolutionary Biology; Joel Abraham, Ph.D. candidate, Ecology and Evolutionary Biology; Finote Gijsman, Ph.D. candidate, Ecology and Evolutionary Biology; Erin Phillips, Ph.D. candidate, Ecology and Evolutionary Biology