Phosphorus Cycle - Nutrient Cycles

Phosphorus is a very important nutrient because of its role in the form of phosphate, in reactions that store and release energy. The availability of phosphates often becomes a limiting factor in ecosystem productivity. The reservoir pool of phosphorus is in crystalline phosphate rock and the compartments in phosphorus cycling involve organisms, soil and shallow marine sediments. Tie natural form in which Phosphorus is available is inorganic phosphate. Through erosion and weathering of rocks, inorganic phosphate is made available to plants that absorb it from soil or in the case of aquatic plants from the water. Once taken up by the plant the phosphate may become part of ATP (adenosine triphosphate), nucleic acid or some other organic compound.

The phosphate may be returned to the soil or sediment when the plant dies and decomposes. Phosphorus may also be passed to the consumer or get incorporated into the cell body of the decomposers. In consumers the phosphorus may be incorporated into the bones and teeth and thus it remains bound for a long period of time. Some of it is excreted as waste and is immediately available to the decomposer. It may by a short loop be converted back to inorganic phosphate and be assimilated by the plants. On the other hand, it may be tightly bound to iron, calcium and aluminium as insoluble compounds and be washed off or lost in sediments.