Page 88 - Science Course 2 (Book 2)
P. 88
Mo10-L2b: What is the Phosphorus Cycle?
The phosphorus cycle moves phosphorus among three Earth systems.
Phosphorus, which is not found in nature as an element, forms
compounds with oxygen called phosphates (PO4).
Rocks exposed at Earth’s surface release phosphates when they
weather.
Dissolved phosphate molecules move in liquid water through the water
cycle.
They eventually reach lake bottoms or the seaf oor, where they are
deposited along with sediment.
Plants absorb phosphorus from either soil or water.
Animals take in phosphorus when they eat plants or when they eat other animals that have eaten plants.
These phosphates return to the soil as part of animal waste or as part of decomposing organisms.
Key Concept
What is the Phosphorus Cycle?
How do Earth systems interact in the phosphorus cycle?
80
