Celia Murphy-Braunstein ’25



Project Title

Glimpses of Late-Cretaceous Ocean: Reconstructing Marine Environment From Foraminifera

Presentation Link

View Celia's Presentation

My internship centered on collecting and processing foraminifera fossils from sediment core samples from the North Atlantic. Foraminifera are single-celled zooplankton that form a calcium carbonate shell. These shells incorporate nutrients from their surroundings, where the isotopic composition of such organic matter acts as a record that can educate us on past marine environments. The central samples in my project are foraminifera from the late Cretaceous period between 82-66 million years ago. I helped to collect foraminera fossils from sediment core samples, washed away clay and fine particles to separate the fossils by different size fractions, and prepared them for analysis on a mass spectrometer. Through this internship, I’ve learned more about the mechanisms within ocean productivity and nutrient cycling, and in particular the nitrogen cycle. I now further value paleoceanography for helping us better understand how ocean environments are associated with climate changes. This internship has provided me with invaluable lab experience and introduced me to the process of independent research, which I hope to pursue in the future within the field of geochemistry.

Internship Year


Project Category

Climate and Environmental Science


Sigman Research Laboratory, Department of Geosciences, Princeton University - Princeton, New Jersey


Daniel Sigman, Dusenbury Professor of Geological and Geophysical Sciences, Professor of Geosciences; Crystal Rao, Ph.D. candidate, Geosciences