By: Katie Maxfield, DUSRC CEC Intern
Samantha “Sam” Phelps is a PhD student and DUSRC Project 4 Trainee in the lab of Dr. Nishad Jayasundara.
Sam’s favorite part of her job is the chance to work outside – something not all toxicology lab technicians get to do. Sam studies killifish that have adapted to survive toxic waters in the Elizabeth River near Norfolk, VA. Every spring, she and her colleagues adventure to Virginia to catch killifish from two different sites: one Superfund site, heavily contaminated with creosote from a wood treating facility that used to operate there, and another with clear, clean water and no known contamination.
In the lab, Sam investigates the cellular and molecular developmental impacts of PAH (polycyclic aromatic hydrocarbon) contamination. They ask questions like “How do developmental co-exposures to PAHs and lead or cadmium affect fitness outcomes? What if the killifish also experience thermal or hypoxia stress?”
The killifish she studies have beaten the odds and adapted to live in contaminated waters, and it’s rare that the team even sees any other types of fish at the Superfund site when they go to catch killifish. However, this adaptation comes with some drawbacks: the fish from the contaminated site aren’t as good at tolerating other kinds of stress. “Something about having to evolve to resist that really strong selection pressure made them more sickly” she explained to me. Even after the killifish from the contaminated sites are “raised in clean water for months, something about the ability to overcome the PAHs also makes them less flexible, less adaptable to a changing environment. In the context of climate change, the ability to tolerate extremes is increasingly important.”
Sam was attracted to this project with Dr. Jayasundara’s lab because of the real-world applicability of the problem. With her background in biochemistry and neuroscience, Sam had worked in research labs before, first as an undergraduate and then as a technician in an academic research lab before beginning graduate school. She knew she didn’t want her job to be solely lab-based. “I wanted to be able to make real-world connections,” she explained. “You’re studying something in a tube, and it’s so hard to conceptualize how it relates to anything in the real world.” Thus, when this opportunity arose, she jumped at it.
In the lab, Sam runs experiments exposing embryos to various chemicals, measuring their oxygen consumption to estimate mitochondrial function, and observing behaviors that hint at neurodevelopmental effects. Collaboration is also a major component of her work. “I literally could not do this alone,” Sam said. Her field work requires long days driving to the sites, catching fish at both sites, and transporting them safely back to the lab. Even then, the day isn’t done, because Sam and her colleagues have to make sure the fish are settled in their tanks. Sam appreciates that though some of her lab mates don’t work directly with the killifish, they still help out with caring for them. It strengthens the lab community and brings in undergrads, grad students, and their lab manager. She emphasized that the lab culture is great and that she appreciated the amazing mentorship of Dr. Jayasundara. Sam’s path to a PhD has been deliberate. Her goal has always been to have her own lab and mentor students closely. “I really like mentoring students, that one-on-one relationship,” she says. She looks forward to TAing a small class alongside her advisor next fall.
