Checkups for Salt Marshes

Finding Foraminifera

At the center of Geraci’s research are foraminifera or "forams," microscopic single-celled organisms that scientists increasingly recognize as powerful environmental indicators of marsh health. “They're like a canary in the coal mine,” she said. “They're really sensitive to salinity, sea level rise, coastal acidification and pollution, and they can tell us a lot about marsh health.”

Traditional monitoring often focuses on marsh vegetation, but microbial communities may reveal ecological stress much earlier.

TNC Research Award

The TNC funding will help pay for the genetic sequencing needed to identify microbial communities. “Sequencing can be expensive, so the award allows us to do this work on a broader scale,” she said.

After collecting sediment samples from marshes across the state, Geraci and her collaborators use a method called metabarcoding—a type of DNA sequencing—to identify organisms living in the samples. “With metabarcoding, we take a sediment sample, extract it and then tag all the different forams that might be there and determine their overall diversity,” she said.

Mud to Marsh: How Well Is it Working?

Her research focuses on marsh restoration projects that add thin layers of sediment to help raise marsh elevation and counteract sea level rise. By comparing restored and non-restored marshes, the team hopes to understand how ecosystems respond to these interventions.

“We go out into the marshes to assess what their overall ecosystem health is, inform people where the marsh is going or how the restoration is affecting the marsh,” Geraci said.

Leveraging Scientific Partnerships

The project brings together scientists from multiple organizations, including Dr. Kenneth Raposa at the Rhode Island Department of Environmental Management (DEM) and Dr. Decatur Foster, a conservation biologist with the Environmental Protection Agency. By pairing her microbial analysis with other monitoring efforts, Geraci hopes to create a faster and more responsive way to evaluate restoration projects.

“Hopefully we can make a more robust long-term tool that potentially an agency like DEM could implement for themselves,” she said.

Community Conversations

Geraci is happy to answer questions or compare notes with community members who stop to ask about her research. “One of the best parts of my research is interacting with the people and how they connect with the marsh throughout their life,” she said.

During one field visit, she spoke with a longtime resident who had watched the marsh change dramatically over decades. “They remembered the salt marsh being a lot healthier with a lot more shellfish,” Geraci said. “They were appreciative that someone was looking into it, but they were also sad that they no longer could enjoy the same things that they used to.”

Those conversations reinforce why understanding marsh ecosystems matters, she said, not only for scientists but for the communities who depend on them.

“We’re hoping to detect the signals of stress in a marsh before larger changes, such as vegetation loss or erosion really become visible,” Geraci said. “This work helps us guide decisions to keep Rhode Island’s marshes healthy.”