Temporal and Spatial Patterns of Internal Phosphorus Recycling in a South Florida (USA) Stormwater Treatment Area

摘要: Large constructed wetlands, known as stormwater treatment areas (STAs), have been deployed to remove phosphorus (P) in drainage waters before discharge into the Everglades South Florida, USA. Their P removal performance depends on internal cycling under typically hydrated, but with occasionally desiccated, conditions. We examined spatial and temporal capacity different hydrologic conditions along a STA flow path. While inflow soils are enriched, outflow region of wetland contained P-unsaturated minimal net recycling bound soil water column plant-available P. The outflow-region were characterized by low porewater soluble reactive (SRP) (≤40 μg L) high total sulfide (TS) (2-9 mg concentrations, ammoniacal nitrogen (TAN) SRP flux rates that averaged 1.51 0.002 m d, respectively. Pronounced increases surface-water concentrations SRP, dissolved organic (DOP), TAN observed immediately after rehydration cell an extended drought. Elevated persisted at outfall for several months thereafter, resulting annual concentration nearly threefold higher than long-term mean. Relative processes can occur during periods inundation, such sulfate-enhanced release from matter mineralization or iron formation, aerobic oxidation prolonged dryout is more significant biogeochemical process compromising retention STAs.