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Most people pass retention ponds without giving them a second thought.

But for Jonathan Terzado, a master's candidate in marine science and oceanography at ×î´ó×ÊÔ´²É¼¯Íø's Harbor Branch Oceanographic Institute (HBOI), those ponds tell an important story about how water moves through South Florida and what happens when nutrient pollution follows.

Working under I-SENSE faculty fellow and HBOI researcher Dr. Jordon Beckler in the Geochemistry and Geochemical Sensing Lab, Terzado is helping monitor nutrient levels in stormwater retention ponds on FAU's Boca Raton campus. These ponds are designed to collect runoff from across campus, but the water they capture often carries elevated nutrient levels from the surrounding landscape.

"At a basic level, we're studying how rainwater moving across campus carries nutrients into ponds, and whether those ponds, and new tools like the SOXPRO system, are actually helping remove that pollution before it moves downstream," said Terzado. "The goal is to figure out practical ways to reduce nutrient pollution before it reaches canals, estuaries and the ocean, where it can harm sensitive ecosystems."

In Florida, that connection matters. What happens on land can directly affect waterways, estuaries and coastal ecosystems miles away. Understanding that pathway, and finding ways to interrupt it, is at the heart of Terzado's research.

The project evaluates the effectiveness of the SOXPRO system, a nutrient mitigation technology designed to improve water quality within stormwater systems. To determine whether it is working, researchers monitor nutrient concentrations before and after installation while tracking factors such as rainfall, pond water levels and other natural processes that influence water quality.

That work recently led Terzado to an unusual task: mapping the bottom of a campus pond using an experimental technique blending his research with "some good old fishing ingenuity."

Using a castable sonar device similar to the fish finders commonly used by anglers, Terzado collects depth measurements throughout the pond. The device sends sound waves into the water and measures how long it takes for the signal to bounce back from the bottom. Combined with GPS data, those measurements allow him to create detailed maps of the pond floor hidden beneath the surface.

"Mapping the depth of the pond allows us to estimate how much water each pond can hold," said Terzado. "This is necessary for interpreting changes in nutrient concentrations, since those changes depend on both inputs and the amount of water present.

The maps are combined with water quality measurements collected using field sensors and weekly water and sediment samples analyzed in the lab. By bringing those datasets together, Terzado can track how nutrients move through the system and evaluate whether the ponds, and technologies like SOXPRO, are effectively preventing pollution from traveling downstream.

Understanding these patterns matters because nutrient pollution does not stay in one place.

"Excess nutrients are a major driver of algal blooms," said Terzado. "These blooms can block sunlight from reaching submerged vegetation and degrade overall water quality. In more severe cases, they can lead to low-oxygen conditions that cause fish kills and harm aquatic ecosystems."

And the impacts extend well beyond campus boundaries.

"These issues don't just stay in the ponds," he said. "Stormwater eventually moves through canals and estuaries and can make its way to the coast, where it can impact systems like seagrass beds and coral reefs."

For Terzado, one of the most rewarding aspects of the project has been seeing how dynamic these systems can be.

"The most interesting part has been seeing how much water levels change between the rainy and dry seasons," he said. "It really highlights how important these ponds are in managing stormwater across the larger drainage system."

The experience has also strengthened his interest in understanding how pollutants move through aquatic environments and identifying practical solutions that can make a difference.

"In Florida, what happens on land directly impacts coastal ecosystems," said Terzado. "Finding effective ways to interrupt that pathway is something I'd like to keep working on."

By helping researchers better understand how stormwater systems function, Terzado is contributing to practical solutions that could reduce nutrient pollution before it reaches Florida's waterways, estuaries and coastlines.