Phosphorus Cycle• Q: What is the phosphorus cycle?• A: The phosphorus cycle is the

movement of phosphorus from the environment to organisms and then back to the environment.

• Q: Where is phosphorus found?• A: Phosphorus is mainly found in soil

and rocks.• Q: Why is phosphorus important to life?• A: Phosphorus is in our DNA, bones and

teeth.

Phosphorus Cycle

Erosion: 1Runoff: 2 Plants absorb through soil: 2 1/2Consumption: 3Decomposition: 4

Phosphorus Cycle• Plants absorb phosphates through the soil• Animals absorb phosphates by eating plants or

plant-eating animals.• When animals and plants die, phosphates will

return to the soils or oceans again during decomposition.

• After that, phosphorus will end up in sediments or rock formations again, remaining there for millions of years.

• Eventually, phosphorus is released again through weathering and the cycle starts over.

• Phosphorus is never in the atmosphere.

Human Impacts on the Phosphorus Cycle• Like nitrogen, increased use of fertilizers increases

phosphorus runoff into our waterways and contributes to eutrophication.

• Eutrophication: a process where water bodies receive excess (too much) nutrients that cause excessive (too much) plant growth.

What’s important1. Most phosphorus is found in rocks and soil.2. Phosphorus is in our DNA and bones and

teeth.3. Excess phosphorus contributes to

eutrophication (too much plant growth).