Dissolved Inorganic Phosphorus (DIP) aka Soluble Reactive Phosphorus (SRP) Disolved Organic Phosphorus (DOP) Particulate Phosphorus (PP) Total P = DIP + DOP + PP Found in the form of Phosphates (PO 4 -3 ) Important to plants, animals, and microbiota Growth – Limiting Nutrient
Weathering of Apatite Point Sources Sewage, Urban Runoff Nonpoint Sources Agriculture, Animal Waste, Fertilizers Modes of Entry to Aquatic Systems Precipitation (dust in air), Groundwater Adsorption, Surface Runoff
Decreases Downstream Can occur faster than needed for growth Rate of uptake dependant upon how much organic matter there is to take it in, and the metabolism of those constituents
How does the solubility of Fe influence the phosphorus redox reactions? As a result, explain how sulfur and iron trapping influences the concentration of phosphorus in the hypolimnion at overturn in a lake. Others….
Iron trap for P - In oxygenated waters, iron is present as Fe 3+ (ferric) pH < 7 : Fe 3+ + PO 4 3- : FePO 4 (Vivianite) pH > 7 : Fe 3+ + PO OH- : Fe 2, OH, PO 4
Fe 3+ conversion to Fe 2+ releases PO 4 3- Sulfur trap may lower iron concentrations enough to allow some phosphate to remain at overturn All these reactions mediated by bacteria