Science Serving Maryland's Coasts

Olivia Lopez, University of Wisconsin Madison

Class Year: 
2019

Project Title: 

Phosphorus Uptake in Floating Wetlands: A Mass Balance Approach

Abstract: 

The health of marine environments situated near developing coasts, like the Chesapeake Bay, is threatened by mass-inputs of nutrients that run off the land. In an attempt to mitigate eutrophic events in aquatic environments, scientists have deployed Floating Treatment Wetlands (FTWs), which mimic a natural wetland’s ability to remove excess nutrients from flowing water. Scientific literature on the behavior of FTWs in lakes and stormwater ponds supports the success of this innovation, however, studies testing the potential of FTWs in estuarine waters is lacking. This study utilized mesocosms to imitate the behavior of FTWs in brackish environments. Mesocosms consisted of a tank filled with ambient estuarine water, an FTW in which Spartina patens was established, and a plumbing system that kept water flowing in and out at a consistent rate. Wetland mesocosms were compared to control mesocosms, which did not contain Spartina patens. The nutrient of interest for this experiment was Phosphorus (P), and uptake of P within wetland mesocosms was determined by calculating the difference between the concentration of P in inflowing and outflowing water. We hypothesized that wetland mesocosms would show greater uptake P than control tanks over the entire 5-week experiment. Results showed wetland mesocosms removing less P than control mesocosms until the fourth week. It was determined that this outcome was likely due to fertilizer leeching into the tanks containing the Spartina patens at the beginning of the experiment, but further research is necessary to support this assumption.