Phosphorus loading to the northern Everglades has led to a number of ecological changes. Stormwater Treatment Areas (STAs) are large constructed wetlands which have been built primarily on agricultural land, designed to reduce the total phosphorus (TP) concentration of agricultural runoff entering the northern Everglades. Problems such as infilling with detrital/organic matter and phosphorus re-release during decomposition can be associated with emergent vegetation wetland systems. These treatment wetlands promote the biological removal of phosphorus by utilizing both emergent and submerged aquatic vegetation (SAV). Effectiveness of P removal utilizing submerged aquatic vegetation was studied in a newly created system; STA 1 West, Cell 5b which is dominated by SAV. Water column, surficial sediments and vegetation samples were obtained from 120 stations within the 928 hectare treatment wetland. All samples were analyzed for TP while the water column samples were also analyzed for dissolved organic phosphorus (DOP), soluble reactive phosphorus (SRP) and particulate P (PP).

GIS maps indicated preferential phosphorus uptake spatially within the wetland. Percent removal of TP, DOP, and SRP the water column was determined utilizing the mean concentrations of the inflow and outflow stations. TP yielded a removal of 78% from an inflow mean of 0.146 mg L^-1 to an outflow of 0.031 mg L^-1. The inflow DOP averaged 0.0303 mg L^-1 and the outflow DOP was 0.015 mg L^-1 yielding a 51% reduction. SRP yielded a removal of 82% from 0.082 mg L^-1 to the outflow concentration of 0.015 mg L^-1. These removal percentages are promising, in particular for SRP, and suggest that this SAV-dominated STA is an effective alternative to traditional emergent vegetation dominated treatment wetlands.