Environmental researchers produce a stream of data

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Freshwater ecosystems emit nearly 70 million metric tons of carbon into the atmosphere annually. “Or 70 million individual [plane] tickets from New York to Paris,” says Amanda DelVecchia, an assistant professor in the UNC College of Arts and Sciences’ geography and environment department.

DelVecchia manages the UNC-Chapel Hill Freshwater Ecology and Biogeochemistry Lab. The lab’s current study, the MacroGas Project, questions how different stream characteristics affect how much greenhouse gas is produced or released into the atmosphere from watersheds.

Research in the DelVecchia lab uses data from the National Ecological Observatory Network. This National Science Foundation effort connects 28 freshwater sites nationwide, which pool their data to better understand how freshwater ecosystems in the U.S. change.

Recent data from the lab suggests the highest concentrations of carbon dioxide are associated with warm, gentle-sloped streams — like the ones often found in the Piedmont region of North Carolina. Each fall, winter and spring, DelVecchia’s team of students and postdoctoral researchers visit one of these streams — New Hope Creek in Durham — to capture a variety of measurements, from water speed to temperature.

The lab focuses on areas with heavy gas release, and their methods involve taking one measurement in an accessible and deep part of the stream. The more they do it, the more data and experience they will get — and the more she hopes to refine current methods to fill the gap in biogeochemical research.

Amanda DelVecchia (Emmy Trivette/UNC Research)

Pooling knowledge

To take their measurements, DelVecchia’s team installs nine different sensors at the start and end of each pool in New Hope Creek to uncover how much carbon dioxide and oxygen releases into the atmosphere.

They use a homemade gas chamber that captures gases on top of the water and provides real-time data for emissions. Constructed using PVC pipe, a plastic sampling bag and a bit of mechanical engineering, the chamber isolates gases coming off the water and provides an estimate of greenhouse gas flux.

This tool is managed by Nguyen Tien Anh Quach, a first-year doctoral student in DelVecchia’s lab.

“At first, everything was so new,” Quach says. “I did not know what I was doing, just tagged along to learn about the methods. But I knew they would be useful for my project.”

Quach’s previous work focuses on how insects interact with freshwater ecosystems. While he didn’t have a gas background going into the MacroGas Project, he’s now a leader in the lab thanks to DelVecchia’s guidance. Soon he will begin fieldwork for his doctoral project to understand if and how freshwater macroinvertebrates contribute to greenhouse gas emissions.

“She wants all her students to understand how these processes work,” Quach says. “If you don’t get it, or if she’s going too fast or too slow, she will adapt to your learning ability.”

DelVecchia prioritizes her lab as a learning space. She offers a first-year seminar that includes optional fieldwork for students who want the experience.

“Many students are excited to get out there to collect samples and see the connections of what we’re doing in class,” DelVecchia says. “I’ve always loved fieldwork so much, since my first summer in college. I feel very at home with those processes around me.”