Horn Point scientists track how microplastics move through the watershed

November 14, 2022
The game-changing Short-wave Infrared Radiation Microscope detects the different wave-lengths and patterns of light different plastics emit.

Scientists at the University of Maryland Center for Environmental Science’s Horn Point Laboratory have embarked on a research project that will lay the foundation for plastic research in the Chesapeake Bay. The two-year project, funded by the National Oceanic and Atmospheric Administration’s Marine Debris Program, will track how microplastics move through the Choptank River watershed on the Eastern Shore of Maryland.

Thanks to a $30,000 matching grant from the Mid-Shore Community Foundation (MSCF) and a group of generous donors who met the match, a short-wave infrared (SWIR) microscope will be purchased.  This camera microscope system transforms the project. Project Co-leaders are Drs. Jamie Pierson and William Nardin.  Pierson stated, “We are thankful for the support we have found with people in the local community who contributed to our work on microplastics in the Choptank River.  With this new microscope we will be able to tell not only how much microplastic is in our samples, but what are the kinds of plastic in different parts of the river.”


Larger plastics such as tires along the shoreline will be identified using a drone carrying a high definition camera, much like that on the SWIR Microscope.

Plastic samples of all sizes, from plastic bags to microplastics barely invisible to the naked eye, will be collected and examined. Along with the SWIR microscope, a drone outfitted with a special camera will be used to scope out larger plastic debris in the watershed from above. Both devices can identify different types of plastics, from plastic bag from beach ball to water bottle. Experiments will look at six different types of plastic, which degrade differently and have different densities, and how they may be trapped or move differently in different places in the river at different times of year.

“Potentially, we’ll be able to make the connection between bigger pieces of plastic in a marsh that break down, and the pieces feeding into river system leading to microplastics in the water. We’re hoping to figure out if different types of debris get moved in different ways,” said Pierson.


Degradation boards holding samples of six different plastics are placed in strategic field sites to evaluate degradation - photo courtesy of Dave Harp

The project will also create a group made up of experts and stakeholders that will advise the research in specific ways to ensure that the outcomes of the project are relevant to policy makers and directly inform management actions regarding plastic marine debris.

“The goal is to develop a budget that illustrates plastic debris input and retention in marsh and open water habitats of the Choptank river system,” said Assistant Professor William Nardin. “Ultimately, this information will allow stakeholders to examine how plastic debris deposition differs across habitats, different flow regimes, and different plastic loads, and to assess potential management strategies to mitigate plastic pollution.”

Studies have estimated that up to 95% of the waste that accumulates on shorelines, the sea surface, and the seafloor is plastic. To date, most published studies on plastic debris have focused on marine ecosystems and not estuaries, rivers, or freshwater systems. Even fewer studies have focused on the interaction of coastal wetlands, such as underwater grasses or marshlands, and the accumulation of microplastics.  

Water samples, taken at identified sites in and along the banks of the Choptank River during all 4 seasons, will help identify how different plastics may be trapped or move in various places in the river at all times of year.

Large pieces of debris are most obvious, but increasing attention has been paid to microplastics, which are less than 5 millimeters in size, or smaller than a pencil eraser. These smaller particles have specific and important human and ecological health implications because they can enter the food chain when they are ingested by the creatures at the base of the food chain.  

All of the data gathered will be made available to stakeholders and policymakers from agencies such as NOAA and the Maryland Department of Natural Resources, as well as local agencies and NGOs, to be applied to coastal wetland systems, locally and globally.

Learn more about the Microplastics Marine Debris Project

The Horn Point Laboratory, located on more than 800 acres on the banks of the Choptank River on Maryland's Eastern Shore, has advanced society’s understanding of the world’s estuarine and ocean ecosystems. Horn Point scientists are widely respected for their interdisciplinary programs in oceanography, water quality, restoration of seagrasses, marshes and shellfish and for expertise in ecosystem modeling. With ongoing research programs spanning from the estuarine waters of the Chesapeake Bay to the open waters of the world's oceans, Horn Point is a national leader in applying environmental research and discovery to solve society’s most pressing environmental problems.