over time, rain and weathering causes rocks to release phosphate ions and other materials. This inorganic phosphate is then distributed into the soil and water. plants take up inorganic phosphate from the soil. the plants may then be consumed by animals. Once in the plants or animal, the phosphate is incorporated into organic materials that break down organic matter to inorganic forms of phosphate. this process is known as mineralisation. Phosphate in soil can end up in waterways and eventually oceans. once there, It can be incorporated into sediments over time.