Elizabeth Wallace ’20



Project Title

Fish Ecology from Otoliths (Ear Stones) Past and Present

Presentation Link

View Elizabeth's Presentation

Certificate(s): Visual Arts

I studied changes in the trophic level of four species of commercially important fish in the Gulf of Maine. Changes in trophic level indicate alterations in the health and structure of the ecosystem due to overfishing or changes in global climate. Nitrogen isotopes in the fish’s body provide a quantitative measurement as the ratio of heavy-to-light isotopes increases with trophic level. I measured the ratio of nitrogen isotopes in the fish’s otoliths, or ear stones, which grow throughout the fish’s life and can be preserved over long periods of time. I compared the trends in nitrogen isotopes of otolith samples from the past 40 years with the stomach contents of fish from a field-survey database. During this internship, I learned new laboratory and data-analysis skills, and I gained an understanding of how a scientific question can be explored through experiments and data analysis. This internship taught me skills that I will use for my senior thesis and gave me insight into a career in research.

Internship Year


Project Category

Biodiversity and Conservation


Sigman and Ward Labs, Department of Geosciences, Princeton University - Princeton, New Jersey


Daniel Sigman, Dusenbury Professor of Geological and Geophysical Sciences, Professor of Geosciences; Bess Ward, William J. Sinclair Professor of Geosciences and the Princeton Environmental Institute; Jessica Lueders-Dumont, Postdoctoral Research Fellow, Geosciences