| A | B |
|---|
| Phosphorus Cycle | The movement of phosphorus atoms from rocks through the biosphere and hydrosphere and back to rocks. |
| Phosphorus | essential element for life-sustaining molecules like DNA and RNA |
| Rocks and sediments | Most phosphorus exists in this form |
| Weathering and erosion | the mechanical process to release phosphorus stored in sedimentary rock |
| Runoff | water that flows over the ground surface rather than soaking into the ground |
| Fertilizer | Phosphate fertilizer applied to fields can run off directly into streams, become part of a soil pool, or be absorbed by plants |
| Excretion and decomposition | Excretion by animals (land or in the ocean) and decomposition of both animals and plants release phosphates on land or in water |
| Dissolved Phosphates | precipitate out of solution and contribute to the ocean sediments. Conversion of sediments into phosphate rocks is a very slow process. |
| Geological Uplift | slowly lift up phosphate rocks from the ocean floor (the rocks thick with phosphates in them) to form mountains |
