Question: where does the phosphorus come from in an ecosystem

title: Phosphorus cycle
text: Phosphorus occurs most abundantly in nature as part of the orthophosphate ion ( PO ) , 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 . 

Answer: answer: On land most phosphorus is found in rocks and minerals. Weathering releases phosphorus of these in a soluble form, where it is taken up by plants and transformed into organic compounds .
answer: 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 .