Water Institute Research Award Recipient Highlights New Strategies for Strengthening Florida’s Salt Marshes

What happens when the nutrients that sustain coastal wetlands begin to overwhelm them? Salt marshes are coastal wetlands that form at the intersection of land and sea. Flooded and drained by saltwater from the tides, mixing fresh and saltwater shapes nutrient availability, vegetation growth, and ecosystem stability. These marshes are vital in protecting shorelines from erosion, supporting fisheries, filtering pollution from freshwater runoff, and buffering storm damage. Land use change and fertilizer application around marshes can cause nutrients to enter salt marshes, affecting their structure and function. Understanding the relationship between nutrient enrichment and salt marsh persistence is critical for effective restoration and management.

New research by University of Florida doctoral student Emory Wellman, supported by a Water Institute Research Award, sheds light on how nutrient enrichment and species interactions influence salt marsh persistence. Her study examines the combined effects of fertilization and ribbed mussels, secondary foundation species, in southeastern salt marshes that form a mutualism with smooth cordgrass, the system’s primary foundation species. Wellman, a student in the Fisheries and Aquatic Sciences program within the School of Forest, Fisheries, and Geomatics Sciences, conducted this research under the advisement of Dr. Anna Braswell. The study, titled “Fertilizer Enhances Production More Than Mussels in a Deteriorating Salt Marsh,” was recently published in the Journal of Applied Ecology and focuses on an urban salt marsh along the Matanzas River in St. Augustine, Florida, a system dominated by smooth cordgrass and shaped by tidal exchange, freshwater runoff, and nutrient inputs from surrounding developed areas

Through a two-year manipulative field experiment, Wellman varied the presence or absence of fertilizer and mussels to examine how nutrient enrichment and species interactions shaped marsh function. She assessed cordgrass production and recovery, nutrient conditions in the soil and water, abundance of marsh fauna, and mussel growth and survival. The results showed preliminary evidence that strategic fertilization could enhance vegetation growth in a rapidly degrading marsh. Specifically, this short-term fertilizer application might help marshes survive during the planning, permitting, and execution of large-scale restoration initiatives. However, further research is needed to better understand the effects of fertilization on the marsh’s mussels and other fauna, as well as logistical considerations of fertilization (e.g., the best fertilizer type, the best application method, etc.). This research paves the way for continued efforts to better understand the resilience of salt marshes.

Wellman and her research underscore the value of funding and enabling early-career scientists. With support from the Water Institute Research Award, Wellman investigates innovative, high-impact questions at the intersection of freshwater and coastal systems.

“The research funding I received from the Water Institute facilitated my inclusion of novel, valuable analyses in this project, including the assessment of plant dislodgement,” Wellman said. “Most importantly, this funding allowed me to conduct the study for two full years, increasing its ecological relevance and realism. I hope to keep working in and around coastal wetlands after finishing my PhD, and I feel very lucky to have had such a great experience conducting and publishing this research.”

The article, “Fertilizer Enhances Production More Than Mussels in a Deteriorating Salt Marsh,” was written by Emory Wellman, Hallie Fischman, Kylie Hollis, Jamila Roth, Zachary Siders, and Anna Braswell. It is accessible from the Journal of Applied Ecology.

Photo taken by Kylie Hollis; used with permission.

May 5, 2026