Nutrient Release from Aquatic Plants

Eutrophication is among the greatest threats to global freshwater. Methods such as floating treatment wetlands (FTWs) utilize aquatic plants to remove excess nutrients directly from the water column. However, plants senesce or die off seasonally, releasing nutrients back into the water. The harvesting of plant tissues can be employed to remove nutrients from the system more permanently. The effectiveness of these strategies is dependent on the amount of nutrients a senesced or dying plant releases. This study submerged four common Missouri macrophytes in conditions that prompted senescence and examined the nutrient concentrations over time. The amount of nutrients released varied among plant species, with emergent plants offering a more permanent sequestration than either submergent or floating plants, which over time release significant amounts of phosphorous and nitrogen compounds. The findings highlight the importance of plant tissue removal in reducing the nutrient concentrations in freshwater systems using FTWs