Reducing nitrogen (N) is one of the biggest challenges facing coastal communities. Too much N fuels harmful algal blooms; degrading water quality and negatively impacting seagrass. These problems continue to threaten waterways across the country. A recent study reveals that while stream restoration can help reduce N entering sensitive coastal ecosystems, finding locations where environmental benefits, public (financial) support and community need all align is far more difficult than expected. Using a combination of hydrology, ecology, economics and social science, researchers identified where restoration projects are most likely to succeed — and where important tradeoffs may limit their effectiveness. 

A.J. Reisinger, associate professor of urban soil and water quality in the UF/IFAS Department of Soil, Water, and Ecosystem Sciences, is a co-author of the study. He contributed to the work through his previous role as a postdoctoral associate at the Cary Institute of Ecosystem Studies. 

“Excess nitrogen is one of the leading causes of water-quality degradation in coastal ecosystems around the world,” Reisinger said. “Its entry point to a watershed system is typically through a stream, which is why we focused on that pathway.” 

Current Challenges

For years, watershed managers and policymakers have invested heavily in stream restoration and green infrastructure projects to help reduce nitrogen entering coastal waters. However, Reisinger and his colleagues found that identifying locations where all restoration goals align perfectly is far more difficult than expected. Areas with the strongest potential for nitrogen removal were often suburban or exurban locations where stream conditions favored natural nitrogen processing. However, the greatest social need and strongest public support for restoration tended to occur in denser urban neighborhoods with less green space. 

“This is a major challenge for environmental management,” Reisinger noted. “Projects that attempt to maximize environmental performance, economic value and social equity all at once may ultimately produce only moderate outcomes in each category.” 

The study also found that stream restoration can meaningfully reduce nitrogen but likely cannot solve the problem alone. Restoration projects reduced watershed nitrogen loads entering coastal systems by roughly 12% under the best circumstances. The researchers suggest watershed managers rethink how restoration projects are targeted and how different environmental goals are prioritized. 

Reducing Nitrogen in Florida

Now working at the University of Florida, Reisinger sees strong parallels between the study’s findings and the environmental challenges facing the state’s coastal watersheds. 

“Florida has many of the same pressures we studied in the Chesapeake Bay region,” Reisinger said. “We have rapid urban and suburban development, aging infrastructure, stormwater runoff and excess nitrogen affecting estuaries, springs and coastal waters.” 

Florida’s waterways are especially vulnerable to nutrient pollution. Reasons include the state’s shallow groundwater systems, high rainfall and extensive coastal development. Notably, excess nitrogen contributes to degraded water quality in systems such as the Indian River Lagoon and Tampa Bay. 

One of the most relevant findings for Florida involves septic systems. These are significant nitrogen sources in many parts of the state. 

“The study showed that lower-density suburban areas outside centralized sewer systems can contribute disproportionately high nitrogen loads to nearby waterways,” Reisinger said.

The research also highlights the importance of understanding how hydrology influences nutrient management. Effective removal depends heavily on how water crosses the landscape. In Florida, groundwater interactions, storm intensity and flow conditions all affect whether restoration efforts will achieve the desired outcomes. 

Future Strategies

Reisinger noted that the findings reinforce the need for targeted, science-based restoration planning rather than assuming every project can achieve every objective simultaneously. 

“The main takeaway from this work is that we may need different strategies for different goals,” he said. “Some areas may be best suited for nutrient reduction, while other places may be priorities for urban greening, flood mitigation or community access to green space.” 

He added that Florida’s rapidly growing coastal communities make this type of integrated planning increasingly important. 

“As we continue to grow, balancing environmental protection with community needs will become even more critical,” Reisinger said. “Studies like this help us better understand where restoration investments can have the greatest impact and where additional approaches may be needed.” 

Environmental quality, our tourism and fisheries industries and community resilience all depend on healthy coastal ecosystems. Combining ecological science with social and economic analysis provides a more realistic understanding of how restoration decisions affect both waterways and people. Additionally, carefully targeted investments may produce the greatest long-term benefits for Florida’s coastal communities. 

The paper, “Sweet Spots for Nitrogen Reduction in a Coastal Watershed,” was published in Nature Sustainability and was supported primarily by the U.S. National Science Foundation Coastal Science, Engineering and Education for Sustainability program, along with additional support from the NSF Long Term Ecological Research and Long Term Research in Environmental Biology programs. The research also received support from the U.S. Department of Agriculture Economic Research Service. Read the full article here: https://www.nature.com/articles/s41893-026-01828-5 

Featured image above of a creek with a small waterfall by Tyler Jones, UF/IFAS photographer.

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