The phosphorus cycle is a biogeochemical process describing how phosphorus moves through the biosphere, the hydrosphere, and the lithosphere.

The phosphorus cycle is a biogeochemical process describing how , the , and the . The phosphorous cycle does not include the because very little phosphorus circulates through as a gas.

Like all cycles, this one does not have a start nor does it have an end. You can see the basics of the phosphorus cycle in the image below.

Most phosphorus is found in rocks, so we'll start looking at the cycle there.

As rocks are broken down and , the phosphorus is released. A form of phosphorus is then taken up from the soil by plants. Herbivores consume these plants and ingest phosphorus while doing so. Animals that consume the herbivores obtain their phosphorous through the herbivores. All animals excrete phosphorus through their urine and and feces, releasing it back into the soil.

When either the plant or the animal dies, such as fungi and bacteria break down the body and phosphorous is released into the soil again.

Phosphorous enters rivers and other waters through precipitation, runoff, or through organisms that enter or live in the water. Organisms that die in the ocean return their phosphorus to sediments in the water (if the organism wasn't consumed by another organism). Over time, these sediments may form rocks or the phosphorous may be used by aquatic plants.

The form of phosphorus changes throughout this cycle. To learn more, see this link.