Environmental Internship Program - 2023 Booklet

Tacy Guest ’26
ECOLOGY AND EVOLUTIONARY BIOLOGY
Certificate: Environmental Studies
PROJECT TITLE
Investigating Nitrogen
Allocation in Corals and
Their Symbionts
ORGANIZATION(S)
The Ward Lab,
Department of
Geosciences,
Princeton University
LOCATION(S)
Princeton, New Jersey
MENTOR(S)
Bess Ward,
William J. Sinclair
Professor of Geosciences
and the High Meadows
Environmental Institute;
Moriah Kunes, Ph.D.
candidate, Geosciences
I worked with The Ward lab to standardize
a method for separating coral tissue from
the symbionts that live within the tissue.
Coral is composed of coral tissue and singlecelled
photosynthetic algae symbionts called
zooxanthellae. The zooxanthellae undergo
photosynthesis and provide energy and fixed
carbon to the coral, but little is known about
how they contribute to nitrogen uptake.
Understanding these relationships is critical
to the future preservation of coral species. To
understand the nitrogen uptake however, it is
necessary to separate the coral tissue and the
symbionts. While many methods exist in the
literature, there is no standardized method, and
the cross contamination between the tissue and
the zooxanthellae in existing methods has never
been quantified. I tested different variations of
the method by preparing samples, assisting in
cell counts and running the mass spectrometer,
a machine that detects the nitrogen and carbon
content of a sample. I also participated in the
data analysis that followed these experiments. I
practiced technical lab techniques and learned
troubleshooting techniques for the mass
spectrometer. I’m excited to continue working
with The Ward Lab through my sophomore year
and on my junior paper and senior thesis.
CLIMATE AND
ENVIRONMENTAL SCIENCE
25