Students use DNA sleuthing to protect Chesapeake Bay plant species

December 12, 2022


Sweaty biology fieldwork in the Chesapeake Bay tends to be an incredibly effective icebreaker for first-year students.

“They’re wearing hip waders, it’s usually 90-something degrees, and they’re all tromping around,” said associate professor of biology and Environmental Studies Program coordinator Carrie Wu. Her class, Genetics in the Environment, doesn’t just invite new connections. The students’ hands-on work supports local conservation efforts too. 

The class concentrates on Phragmites australis, an invasive plant resembling bamboo that can grow 15 feet tall. Spreading aggressively in wetlands, the reed forms a dense thicket that destroys food and nesting habitats. The mats trap sediment, raising soil levels. Landowners find that the towering plants block views and lower property values. 

“Once Phragmites starts becoming established, the ecosystems go from high to low diversity habitats,” Wu said. “Right around the Virginia Beach area, the concentration of Phragmites has exploded.”

But, as students discover in their course-based undergraduate research experience with Wu, the area is also home to a native plant species Phragmites americanus that land managers want to protect. Distinguishing between the two species is crucial for controlling the invasive one.

When Wu first joined the faculty, she sought to offer experiential service learning. Colleagues connected her with Kevin Heffernan, stewardship biologist in the Division of Natural Heritage for the Virginia Department of Conservation and Recreation. Heffernan had seen scientific literature on genetic testing for Phragmites, but his resources were limited, Wu recalled. She realized her students could help.

We do the collections and we try to morphologically identify the plants. Then we go through all the steps to extract the DNA.
headshot of Carrie Wu
Carrie Wu


“Each year, Kevin takes us to a different natural area preserve,” she said. “We do the collections and we try to morphologically identify the plants. Then we go through all the steps to extract the DNA.” Wu doesn’t know in advance what they’ll find — she’s teaching the process.

When this fall semester started, she shared an email with her class from Heffernan about treating the invasive Phragmites that students had identified the previous semester. She told her students: “What you’re doing is actually informing how local land management is occurring.”

The class went to the New Point Comfort Natural Area Preserve near Matthews, Virginia. There, they broke into teams and sampled along linear routes. At each site where they collected leaf tissue to bring back to the lab for DNA analysis, they marked the location with a phone app.

They learn geo-referencing and mapping software at UR's Spatial Analysis Lab, Wu said. “It’s nice to be able to have students introduced to that in their first semester.”

First year Katie Camera found Genetics in the Environment through the Endeavor program. “The Phragmites project we’ve been working on, it helps me learn not only the biology, but also how to be a scientific writer and scientific thinker,” she said.

Paxton Calder was also among the students donning waders. “Embracing the idea of using science to do service, I think that that’s really valuable,” she said, adding that the class solidified her plan to pursue a career in research.

Laura Murray-Nerger, a 2015 alum, credited Wu’s course with setting her professional career in motion. She received a Ph.D. in molecular biology from Princeton and is currently a post-doctoral research fellow studying Epstein-Barr virus at Harvard Medical School.

“I learned a great deal about doing research and thinking scientifically,” she remembered. “The course also showed me the importance of collaboration in science and how, working together, we can achieve so much more than we ever could working alone.”