What are the steps of the phosphorus cycle?

1 Answer
Feb 10, 2016


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Phosphorus moves in a cycle through rocks, water, soil and sediments and organisms.

Key steps of the phosphorus cycle:

# Over time, rain and weathering cause rocks to release phosphate ions and other minerals. This inorganic phosphate is then distributed in soils and water.

# Plants take up inorganic phosphate from the soil. The plants may then be consumed by animals. Once in the plant or animal, the phosphate is incorporated into organic molecules such as DNA. When the plant or animal dies, it decays, and the organic phosphate is returned to the soil.

# Within the soil, organic forms of phosphate can be made available to plants by bacteria that break down organic matter to inorganic forms of phosphorus. This process is known as mineralisation.

# Phosphorus in soil can end up in waterways and eventually oceans. Once there, it can be incorporated into sediments over time.

Phosphorus is a chemical element found on Earth in numerous compound forms, such as the phosphate ion (#PO_4 3^-#), located in water, soil and sediments.

The quantities of phosphorus in soil are generally small, and this often limits plant growth. That is why people often apply phosphate fertilisers on farmland. Animals absorb phosphates by eating plants or plant-eating animals.

  • The role of phosphorus in animals and plants

Phosphorus is an essential nutrient for animals and plants. It plays a critical role in cell development and is a key component of molecules that store energy, such as ATP (adenosine triphosphate) , DNA and lipids (fats and oils). Insufficient phosphorus in the soil can result in a decreased crop yield.