Phosphates PO4-3 are formed from this element. Phosphates exist in three forms: orthophosphate, metaphosphate (or polyphosphate) and organically bound phosphate each compound contains phosphorous in a different chemical arrangement. These forms of phosphate occur in living and decaying plant and animal remains, as free ions or weakly chemically bounded in aqueous systems, chemically bonded to sediments and soils, or as mineralized compounds in soil, rocks, and sediments.
Orthophosphate forms are produced by natural processes, but major man-influenced sources include: partially treated and untreated sewage, runoff from agricultural sites, and application of some lawn fertilizers. Orthophosphate is a readily available to the biological community and typically found in very low concentrations in unpolluted waters. Poly forms are used for treating boiler waters and in detergents. In water, they are transformed into orthophosphate and available for plant uptake. Organic phosphates are typically estimated by testing for total phosphate. The organic phosphate is the phosphate that is bound or tied up in plant tissue, waste solids, or other organic material. After decomposition, this phosphate can be converted to orthophosphate.
Phosphate rock in commercially available form is called apatite and the phosphate is also present in fossilized bone or bird droppings called guano. Apatite is a family of phosphates containing calcium, iron, chlorine, and several other elements in varying quantities. The most common variety contains fluorine, and fluorapatite is the main constituent in bones and teeth! Huge quantities of sulfuric acid are used in the conversion of the phosphate rock into a fertilizer product called "super phosphate".
Small amounts of certain condensed phosphates are added to some water supplies during treatment to prevent corrosion and this chemical is used extensively in the treatment of boiler waters. Larger quantities of these compounds can be found in laundering and commercial cleaning fluids. Orthophosphates applied to agricultural or residential lands as fertilizers are carried into the surface water during storm events or snow melt. In addition, storm events can cause the vertical migration of the phosphates into the groundwater system, but because of soils affinity for phosphate, the soil mantle acts as a storage media.
Why Phosphorus Is Important </span>
Phosphorus is one of the key elements necessary for the growth of plants and animals and in lake ecosystems it tends to be the growth-limiting nutrient and is a backbone of the Kreb's Cycle and DNA. The presence of phosphorus is often scarce in the well-oxygenated lake waters and importantly, the low levels of phosphorus limit the production of freshwater systems (Ricklefs, 1993).Unlike nitrogen, phosphate is retained in the soil by a complex system of biological uptake, absorption, and mineralization. Phosphates are not toxic to people or animals unless they are present in very high levels. Digestive problems could occur from extremely high levels of phosphate. The soluble or bio-available phosphate is then used by plants and animals. The phosphate becomes incorporated into the biological system, but the key areas include ATP, DNA, and RNA. ATP, adenosine triphosphate, which is important in the storage and use of energy and a key stage in the Kreb's Cycle. RNA and DNA are the backbones of life on this planet, via genetics. Therefore, the availability of phosphorus is a key factor controlling photosynthesis.
<span>Photosynthesis - KEY Factor At the Base of the Food Chain</span>
Photosynthesis is a complex series of reactions carried out by algae, phytoplankton, and the leaves in plants, which utilize the energy from the sun. The simplified version of this chemical reaction is to utilize carbon dioxide molecules from the air and water molecules and the energy from the sun to produce a simple sugar such as glucose and oxygen molecules as a by-product. The simple sugars are then converted into other molecules such as starch, fats, proteins, enzymes, and DNA/RNA, i.e., all of the other molecules in living plants and animals. All of the of a plant or animal is ultimately produced as a result of this photosynthesis reaction. The equation governing photosynthesis is: