“I study estuaries, where river and sea water meet. These are important areas for biodiversity and biological productivity. I am also interested in the ‘missing plastics paradox.’ People say there’s so much plastic in the ocean, but when you actually measure how much is out there, there isn’t as much as you’d expect based on how much is coming down rivers. I thought, then, that much of the plastic might be getting stuck in estuaries.

“In 2021, a postdoctoral scholar in my research group developed a circulation model to test this idea in the Chesapeake Bay, a big estuary. We found that a lot of the plastic was getting stuck on the shorelines of the bay and wasn’t making it out into the ocean. Looking for confirmation of the idea in the environment, some of my Penn State collaborators and I made measurements in a tidal marsh at the John Heinz National Wildlife Refuge; we pushed long, steel cylinders several meters into the marsh to pull out what we call a core. The deeper you go, the older the marsh is, and the deeper we went, the less plastic there was—presumably because there was less plastic in the environment. We could then calculate how much plastic was deposited over time and estimate how much of it is getting trapped by the marsh.

“There are many research and advocacy efforts to improve the health of estuaries. Plastic is a relatively new area of study. I would be concerned about the zooplankton ingesting microplastics—this could turn out to be a huge problem as it works its way up the food chain. Fish and birds flock to estuaries to feed. There are a lot of nurseries in estuaries, so microplastics trapped there could do more harm than in the open ocean.”