Students Make a Splash to Help Restore the Great Marsh Ecosystem

A group of Honors Biology students walks across the Govs athletic fields to the Barn. Once inside, there’s a mix of hesitancy and excitement as each chooses a pair of brown or green waders. But the waterproof overalls are a welcome fashion accessory a few minutes later when the budding field scientists arrive at the muddy banks of the Parker River in the Great Marsh.

Their assignment? To collect baseline data—including vegetation, insect and fish species—before the removal of a collapsed agricultural culvert. Dating back to at least 1920, it’s likely that farmers built the structure for livestock or equipment crossing over the water. But it has proven to be a barrier to the marsh’s natural tidal flow and, consequently, the broader ecosystem.

“The marsh is designed by nature to take in a lot of water on incoming tides and then drain that water on outgoing tides; that’s part of its natural hydrology,” says Erika Mitkus, director of The Bass Institute at the Bill '67 and Peter '71 Alfond Coastal Research Center. “It’s important to have natural drainage and inflow without any barriers like the culvert. We are stewards of 550 acres of land at Govs, and about 80 of those are part of the Great Marsh ecosystem. Initiating a project like this can be daunting, but it aligns with the purpose of my role,” added Mitkus.

We are stewards of 550 acres of land at Govs and about 80 of those are part of the Great Marsh ecosystem. Initiating a project like this can be daunting...

Specifically, Mitkus serves as the point person to bridge Govs with local environmentalists and agencies, including the Newbury Conservation Commission and Northeast Massachusetts Mosquito Control and Wetlands Management. The latter committed to complete culvert removal given that Govs obtains and funds permitting from the Commission, and monitors compliance with town and environmental laws.

Mitkus also teamed up with Roberta McLain P'07,'09, who teaches ninth-grade Honors Biology, so that students could participate in the real-time longitudinal study. The pair designed curriculum that includes data collection in the marsh before and after the culvert is removed, and advocacy for permit approval by the Commission.

Tracking Nature’s Clues

Students began preliminary data collection around the Corn Creek Culvert in fall 2024. Wearing their waders, they divided into four groups—abiotic (nonliving factors), nekton (aquatic creatures such as fish, crabs, and eels), vegetation, and macroinvertebrates (aquatic insects and worms)—and headed out to collect data at seven sites. Emily Geist ’27 was part of the abiotic factors group measuring dissolved oxygen, turbidity, and salinity of the water upstream and downstream. 

“I liked the idea of being a part of a real science project that would continue for years to come and influence future decisions around culverts,” Geist says of first hearing about the assignment in McLain’s Honors Biology class. “The marsh was like our lab. We brought tools to take measurements and recorded our data on a clipboard. In the end, we compiled data on the health of the marsh and hypothesized what would happen when the culvert was removed.”

In October 2024, Geist, along with Anja Suomi ’27 and Alex Wang ’27, attended a local Conservation Commission meeting to share that data and advocate for permission to have the culvert removed. “Seeing how permits are acquired was a cool aspect of the scientific process that I don’t think students normally get to see,” Geist says.  

Suomi was part of the vegetation group logging plant species in various parts of the marsh. An important lesson that would inform their prediction: When saltwater leaks into the marsh, it changes the chemistry of the marsh and results in higher salinity.

“Plants like cordgrass, which are resilient, can adapt to the saltier climate,” Suomi notes. “Other species, which are more fragile, can struggle to adapt and become endangered. This reduces biodiversity in the marsh and can lead to an unhealthy ecosystem. According to the data we collected, the marsh didn’t seem to be very healthy at the culvert site. The only four plants we found were salt marsh hay, cattails, goldenrod, and cordgrass, which could be due to the amount of seawater being trapped upstream by the culvert.”

Wading Into the Unknown

Culvert removal was completed in January 2025. Mitkus says the second group of students collecting data this spring has already found that the stream has widened. Though it’s now harder for them to cross the stream to gain marsh access during high tide, another species—blueback herring that swim upstream to lay eggs in the marsh—are thriving without the culvert blocking the natural path of the herring run. 

Suomi recalls an unplanned lesson related to herring stranded in the marsh during low tide before the culvert was removed. “We were walking upstream of the culvert, and there were hundreds of fish stuck, so we decided to skip our original assignments and instead work on saving the fish. 

“Before that class, I was scared of touching fish, but I no longer am,” she continues. “I spent an hour-and-a-half standing in the marsh grabbing fish with my bare hands and placing them in buckets and nets to be set free downstream. It was like nothing I’ve ever experienced. It was a great community moment because the whole class was working together toward a common goal.”

Geist shares a similar unexpected experience. “When I first went out into the marsh, I was kind of terrified of the mud and bugs, but with the waders you could just sit down in the middle of the marsh,” she recalls. “And even though I still hate bugs, I was surprised how much I like the marsh, especially around the culvert where it’s secluded.”

And on a broader level, she adds, “One of my biggest takeaways was the lasting impact of what we did. The research conducted in Honors Biology will continue to shape this study and inform future classes that collect data. It will also contribute to a bigger cause.”  

Uncertain Paths to Discovery

Those kinds of takeaways are exactly what Mitkus and McLain were hoping for. 

It’s great to see students get out there and get messy and uncertain—to understand that the answer isn’t always in a textbook.

“It’s exciting that we’re involving students in a real scientific project,” says Mitkus, who estimates that it will take at least five years of data collection to see the impact of culvert removal. “It’s harder to teach in the sense that I don’t know what the answer is going to be, but the learning is more authentic.

“I’m also happy that the school and my colleagues have embraced that approach as a teaching pedagogy. It’s great to see students get out there and get messy and uncertain—to understand that the answer isn’t always in a textbook.”

McLain says that as a microbiologist—typically working in a controlled lab setting where data is more concise—the uncertainty of ecology is something even she had to get used to. “This is good for me because it’s forcing me out of my comfort zone and into much grayer areas where patterns are messier, variables are harder to control, and answers are often incomplete. I saw that same shift in my students who were at first hesitant and, after their first day out in the marsh, told me how fun it was. 

"As an educator, it excites me to expose students to different kinds of sciences and open their eyes to what they can do,” McLain continues. “And it excites them to know that there are a lot of environmental organizations and scientists in the area interested in seeing what happens."