The Search for Microplastics in Blue Crabs

I knew studying microplastic ingestion would be a rewarding experience both personally and professionally, but I had no idea how much this opportunity would prepare me for the future.

For the past 5 years, I have been active in the North Carolina Marine Debris scene and passionate about the reduction of plastic pollution in coastal areas. I coordinated educational events, participated in beach sweeps, and even helped create a Facebook account dedicated to educating North Carolina stakeholders about marine debris. I learned a lot through all these experiences, but I really wanted to participate in microplastic research. This Spring, I was excited and grateful to receive an award from the CNR Enrichment Fund to pursue my research interests.

The purpose of my research project was to chemically break down juvenile blue crabs and evaluate the ingested microplastics. Juvenile crabs are too small to dissect, so I was unable to remove their stomachs and gills to chemically dissolve. I needed to digest the entire crab exoskeleton and all. Unfortunately, during my literature search, I had trouble finding previous studies describing how to chemically dissolve the whole crab. I was starting from scratch, which was exciting and daunting, so I needed to develop my research methodology. Thankfully, my research advisor, Erin Voigt, from the Eggleston lab with the Department of Marine and Atmospheric Sciences was a huge help.

At one point during the methodology testing, I remember feeling frustrated because our planned methods were not working. The digestion liquids we used were just not strong enough to dissolve exoskeletons. It was back to the drawing board for us. After consulting a few outside sources, Erin and I were pointed to a more complex chemical process called wet peroxide oxidation. This was the real deal. The wet peroxide oxidation process is highly reactive, and we were warned to take special care not to let the mixture overheat. When I was mixing the catalyst solution, I remember thinking “Wow, I feel like a real lab scientist!” The first time we tried this option, the crabs were almost fully digested in an hour. Finally, success!

I always get a thrill from looking into microscopes, so I was excited to examine the filtered remnants of our crabs. I was unsure of what we would find. The crabs were collected from the Albemarle-Pamlico Estuary System, and these areas are pretty rural. I was prepared to not find plastics at all. Upon my first glimpse in the dissecting microscope, I saw a small teal speck on the filter. To my surprise, I actually found fragments and fibers of potential microplastic contamination! Since I only visually identified the particles, they might not be of plastic origin. I have never been more excited to see possible plastic pollution in my life.

I know I want to pursue graduate school, but this project solidified that for me. As a graduating senior, this experience was a fantastic way to prepare me for graduate school. I applied for funding, designed an experiment, gained experience budgeting and ordering supplies. The method development process was an incredible learning opportunity. Also, watching my experiment finally work was exceedingly rewarding!