It’s Getting Hot in Here

Katelyn Jones, COL ’24, Fayetteville, PA

Climate change – one problem that will undoubtably plague the future of the planet. Among other global issues, rising global ocean temperatures feels like an out-of-control train car that just can’t seem to be stopped. This threatens the health and survival of marine populations, including those of corals and other cnidarians. Coral reefs are essential communities for tropical and temperate ocean climates, providing shelter for other fish and importantly acting as a carbon sink (as carbon in the environment can be incorporated into their skeletons). However, as ocean heat waves become more frequent, corals are directly impacted.

As important context, corals are animals, even though they might look like rocks or plants. Corals also maintain a symbiotic relationship with single-celled algae (Symbiodiniaceae). These symbionts reside in a special organelle within coral cells and receive shelter in addition to access to inorganic nutrients like ammonium and nitrogen. Also, the coral receives some of the bounty of photosynthates from the algae. The relationship between the symbiont and host, however, breaks down during heat stress. This is called “bleaching” – corals often expel their symbionts, causing them to lose an important source of nutrition. This can lead to starvation, weakening of their skeletons, and possibly death.

This summer, I was honored with the opportunity to work in Dr. Katie Barott’s laboratory at Penn studying aiptasia, a species of sea anemone that serves as a model species for corals. Aiptasia also host symbiotic algae and behave similarly under heat stress. In May, I assisted with a 2-week acute heat stress experiment with the aiptasia. In studying the effects of climate change, many different scales of approach are necessary. Taking a more mechanistic approach, the heat-stress experiment was followed with several physiological assays, including a Bradford for protein content, symbiotic cell counts, chlorophyll content, and the intracellular pH (pHi) of the host cells. We are currently in the process of analyzing this data and are preparing to publish a paper of the results. The goal is to glean some understanding about the mechanistic responses to heat stress to understand the relationship of the symbiosis more clearly. Identifying mechanistic responses to stress is the “basic biology” of tackling the real-world problem of bleaching. It’s kind of like a puzzle – unless you know what the picture looks like, it’s extremely difficult to solve it.

Under the wonderful guidance of graduate candidate Luella Allen-Waller and post-doc Kristen Brown, I have learned such invaluable skills. From planning a project from beginning to end to managing real-time technical errors to using lab instruments, I must give all my thanks to my wonderful mentors for supporting me. I also learned how to code in R, which was a major under-taking and has provided me with great data-analysis skills. This experience has only fueled my fire to continue in research and seek out a career in this academic space. Thank you to Career Services for providing funding for this experience and to the Barott lab for a fantastic lab-home.

This is part of a series of posts by recipients of the 2022 Career Services Summer Funding Grant. We’ve asked funding recipients to reflect on their summer experiences and talk about the industries in which they spent their summer. You can read the entire series here


By Career Services
Career Services