Phosphorus cycle is an example of sedimentary nutrient cycle, since, it moves from land to the sediments at the bottom of the seas, then back to land again. The natural reservoir of phosphorus is earth’s crust. Rocks contain phosphorus in the form of phosphates.
By weathering and soil erosion, phosphates enter streams, rivers and then to oceans. With great movements of the tectonic plates, sea floor is uplifted and phosphates become exposed, on the drained land surfaces. From here, weathering for a long period of time releases phosphates from rocks. Then minute amount of these phosphates dissolve in soil and are absorbed by the roots of the plants. Herbivores and other animals obtain this element from the plants. The waste products and the dead organisms are decomposed by phosphate-solubilising bacteria releasing phosphorus.