Allie Hopper – Semester by the Sea: Studying Oyster Health Responses to PFAS
A little fish in a very large ocean. This is how I felt when I first began my undergraduate experience at NC State, among a student population of almost forty thousand and with little idea of where I wanted my education to take me after graduation. I was passionate about the environment but tried and failed to find my niche in the broad spectrum of specialties the College of Natural Resources offered. I found myself joining Marine Science Club on a whim and had never considered a career in the marine science field until I learned about the Semester at CMAST program. Despite it still being in North Carolina, spending one of my last few semesters at NC State in Morehead City seemed like a daunting and risky commitment, but the wide expanse of research opportunities the program promised drew me in, and I suddenly found myself applying despite my limited knowledge of oceanic and coastal environments.
CMAST became my home this semester and, in addition to my marine-focused coursework, I had the privilege of working in the lab of Dr. Maria Rodgers, an assistant professor in NC State’s Department of Biological Sciences whose research focuses on immunotoxicology in marine organisms. The project I worked on under grad student Jacob Collins revolved around studying the health responses of Eastern Oysters (Crassostrea virginica) to both high water temperature and PFAS, or per- and poly-fluoroalkyl substances. The idea of working with these synthetic chemicals was daunting at first, as I had always considered myself to be more drawn to field work than any chemical or molecular lab work, and I worried that I lacked the background knowledge of both molecular biology and lab protocols necessary to be reliable.
I quickly landed in the role of oyster caretaker, and my daily tasks for the first half of the semester, prior to our exposures, revolved around their wellbeing and acclimation to the conditions of our aquaculture lab at UNC’s Institute of Marine Sciences. These tasks included changing the water in their tanks daily, monitoring the water heaters, and measuring and feeding them a smelly algae concoction dubiously labeled “shellfish food.” Despite the tedious and often slimy nature of my caretaking responsibilities, I found myself developing a fondness for the hardy mollusks as I learned more about their nature and importance to coastal ecosystems. Not only can they filter up to fifty gallons of water per day, but they also protect the coast against erosion from harsh storms or breaking waves by forming reefs, cementing to one another to stabilize shorelines. As my semester progressed, I was provided with articles to help build my knowledge of the molecular processes we would utilize in our lab work, and eventually we began practicing these assays while continuing our aquaculture work. My confidence in both my knowledge and practical abilities continued to grow, and I soon realized I could follow protocols, navigate our equipment, and have an in-depth understanding of the work I was doing. This confidence carried over into my career aspirations, and an idea of what I want to do after graduation started to form and solidify in my mind.
We faced our first snag in the previously smooth operation when we began our trials, which were practiced exposures to the high-water temperatures to be used in conjunction with the chemical exposure to PFAS. Our small sample sizes faced staggering mortalities, and what was meant to be only one trial became three as we made small adjustments to the temperatures to staunch the loss. We eventually found the temperatures at which the oysters could feasibly survive during their exposure to PFAS, and through this portion of our research I not only gained valuable experience in animal husbandry but also witnessed firsthand the types of challenges one might face in research, and how to pivot and recover from them.
Once the PFAS exposures were finished, during which my daily tasks remained constant, we began the lab work that would reveal how the oysters responded on a cellular level to the environment we’d created. I got to choose multiple genes to target in the lab, meaning I was to search for their expression in the data we collected from each oyster’s tissue. The first step of this was to gather tissue samples from every specimen, which involved shucking dozens of oysters and collecting data like their dimensions and weight. I then spent the following weeks extracting RNA from our tissue samples, and using that RNA to synthesize cDNA, or complementary DNA. The cDNA was then used for qPCR, or quantitative polymerase chain reaction, where the cDNA was replicated repeatedly, extracting targeted gene data from it throughout this process. These procedures were completed through a series of steps such as carefully measuring and distributing each necessary solution, followed by centrifuging the samples. With each procedure I set up and each drop of solution I measured, my paralyzing fear of making a mistake that would negate my previous work lessened.
While the lab work portion of the research was the most challenging, it was also, unexpectedly, the most enjoyable and rewarding. Each time I donned my goggles, lab coat, and gloves, it felt like I was transforming into the scientist I’d always dreamed of being. I not only gathered practical skills such as learning how to use each instrument and machine, I also grew to be knowledgeable of the step-by-step molecular processes of each part of the experiment. The more time I spent in the lab, the more I familiarized myself with protocols that have become second nature, such as when to change my gloves, what counts as contamination of a sample, and how to avoid that contamination. The knowledge that I enjoyed doing this type of work was easily as valuable to me as the practical skills I learned, and throughout this semester I was able to set clear goals for where I want to go and what I want to study next – a grad program in environmental toxicology!
I stepped into my research position at CMAST as a self-proclaimed lover of nature with an undirected passion for conservation. Through this opportunity I feel as though I have finally found my niche, not only in the field of marine science, but also in the type of scientific work I enjoy most. Muddying my shoes every now and then in the field is rewarding in its own sense, but stepping up to the lab bench, pipette in hand, is where I now feel the most at home. I now have the knowledge to begin my graduate school applications and, more importantly, the resources and connections needed to feel secure and confident in choosing a program that’s right for me. The field of conservation work is indeed a very large ocean, and I might be a little fish, but this experience has made it hard to believe I ever thought myself lost.