1. Chuck Hansen 3.7.13

2.  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

3.  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

7.  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

8.  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….

10.  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 4 3- + OH- : Fe 2, OH, PO 4

11.  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