Citizen-science project initiated at UMaine applied in National Parks nationwide

Citizen science is a powerful tool for assessing the risk of environmental contamination, according to a new assessment of a nationwide project initiated at the University of Maine.

The Dragonfly Mercury Project encourages students, volunteers and visitors of National Parks to collect dragonfly larvae to measure mercury levels in water bodies.

The continental-scale study is the brainchild of Sarah Nelson, who launched the initiative when she was an associate research professor in the UMaine School of Forest Resources. The framework was adapted and deployed in National Parks nationwide by the U.S. Geological Survey.

The project’s recently published assessment in the journal Environmental Science & Technology includes findings from more than 4,000 citizen scientists who collected 14,831 dragonfly larvae from 457 sites in 100 National Park Service units.

Mercury contamination is the leading cause of fish consumption advisories in North America. The pollutant is cited as one of the top 10 chemicals of major public health concern by the World Health Organization, posing risks to both humans and wildlife.

Compared to more commonly studied fishes, dragonfly nymphs are ubiquitous in water bodies of all sizes — from vernal pools that can be crossed with a single step to large lakes and rivers — on every continent except Antarctica. They are also easy to capture and identify, making them ideal subjects for study. Akin to canaries in coal mines, these ravenous aquatic insects help scientists on the project assess the mercury risk in aquatic ecosystems.

The idea of focusing on dragonfly nymphs came to Nelson when she worked with Schoodic Institute at Acadia National Park to analyze invertebrates that high school students collected for an inquiry-based science course.

“I was attending a poster session where two schools got together to share their findings, and suddenly I realized that both schools had sampled dragonfly larvae, and were seeing a pattern that made a lot of sense given my research up to that point in geochemistry: the dragonfly larvae from one stream that was downstream from a wetland had higher mercury than the mercury in dragonflies from another stream that did not have a wetland upstream,” said Nelson, who now directs research for the Appalachian Mountain Club. 

“This is what they call a eureka moment: seeing the results from these students together made me connect that macroinvertebrates could be just the kind of indicator — or biosentinel — we were looking for, to tell us which water bodies were likely to have higher mercury risk.”

During a later meeting about mercury pollution, Nelson mentioned the monitoring she was doing with high school students using dragonflies. Colleen Flanagan Pritz of the National Park Service Air Resources Division was in attendance and told Nelson that she would like to see the concept deployed in National Parks.

That first year, Nelson and Flanagan Pritz bootstrapped the Dragonfly Mercury Project with no funding and a handful of colleagues.

The project expanded to 11 national parks in 2012 with pilot funding from the University of Maine, then grew to include 25 parks with National Park Service funding in 2013. With UMaine, collaborators at the U.S. Geological Survey (USGS), National Park Service, Dartmouth College and University of Wisconsin-La Crosse joined in writing a proposal that helped the project expand nationwide — over 70 parks were sampled from 2014–15 — and more deeply investigate the water chemistry, sediment and food web interactions of each site.

Contact: Erin Miller,