where is the majority of phosphorus stored on earth
Phosphorus cycle Phosphorus occurs most abundantly in nature as part of the orthophosphate ion (PO4)3âˆ’, consisting of a P atom and 4 oxygen atoms. On land most phosphorus is found in rocks and minerals. Phosphorus rich deposits have generally formed in the ocean or from guano, and over time, geologic processes bring ocean sediments to land. Weathering of rocks and minerals release phosphorus in a soluble form where it is taken up by plants, and it is transformed into organic compounds. The plants may then be consumed by herbivores and the phosphorus is either incorporated into their tissues or excreted. After death, the animal or plant decays, and phosphorus is returned to the soil where a large part of the phosphorus is transformed into insoluble compounds. Runoff may carry a small part of the phosphorus back to the ocean. Generally with time (thousands of years) soils become deficient in phosphorus leading to ecosystem retrogression.[4]
Phosphorus deficiency In plants, Phosphorus (P) is considered second to nitrogen as the most essential nutrient to ensure health and function. Phosphorus is used by plants in numerous processes such as photophosphorylation, genetic transfer, the transportation of nutrients, and phospholipid cell membranes.[2] Within a plant cell these functions are imperative for function, in photophosphorylation for example the creation of stored energy in plants is a result of a chemical reaction including phosphorus. Phosphorus is a key molecular component of genetic reproduction. When phosphorus is present in inadequate levels, genetic processes such as cell division and plant growth are impaired. Hence, phosphorus deficient plants may mature at a slower rate than plants with adequate amounts of phosphorus. The stunted growth induced by phosphorus deficiency has been correlated with smaller leaf sizes and a lessened number of leaves.[3] Phosphorus deficiency may also create an imbalance in the storage of carbohydrates. Photosynthesis, the main function of plant cells that produces energy from sunlight and water, usually remains at a normal rate under a phosphorus-deficient state. However phosphorus usage in functions within the cell usually slow. This imbalance of rates in phosphorus deficient plants leads to the buildup of excess carbohydrate within the plant. This carbohydrate buildup often can be observed by the darkening of leaves. In some plants the leaf pigment change as a result of this process can turn leaves a dark purplish color.