PHOSPHOROUS CYCLE

PHOSPHOROUS CYCLE

• Phosphorus is an important element for all living organisms.
• Phosphorus forms a significant part of the structural framework of DNA and RNA.
• Phosphorus is also an important component of ATP and Lipids (fats and oils).
• Humans contain 80 % of Phosphorus in teeth and bones.
• Phosphorus is an essential nutrient for animals and plants. Insufficient phosphorus in the soil can result in a decreased crop yield.
• In Phosphorous cycle, the Phosphorus moves in a cycle through rocks, water, soil and sediments and organisms.
• The Phosphorous cycle is a slow process when compare to other Biogeochemical cycles.

STEPS INVOLVED IN PHOSPHOROUS CYCLE

Phosphorous cycle

• Phosphorous cycle has four steps. They are

1. Weathering
2. Absorption by Plants
3. Absorption by Animals
4. Return of Phosphorous back to Ecosystem through Decomposition

1) Weathering

• Phosphorous is most commonly found in rocks.
• The phosphorus cycle starts in the Earth’s crust. 
• Weathering is the breakdown of rock into smaller and smaller pieces.
• Weathering causes Phosphate salts to break from the rocks.
• Weather events, such as rain and other sources of erosion, result in Phosphorus (Phosphate salts) being washed into the soil. 

2) Absorption by Plants

• The Phosphate salts dissolved in water are absorbed by the plants. However, the amount of phosphorus present in the soil is very less. That is why the farmers apply phosphate fertilizers on agricultural land.
• The aquatic plants absorb Inorganic phosphorus from lower layers of water bodies. Since phosphate salts do not dissolve in water properly, they affect plant growth in aquatic ecosystems.

3) Adsorption by Animals

• The animals absorb Phosphorus from the plants or by consuming plant-eating animals.
• The rate of the Phosphorus cycle is faster in Plants and Animals when compared to Rocks.

4) Return of Phosphorous back to Ecosystem through Decomposition

• When the plants and animals die they are decomposed by microorganisms.
• During this process, the Organic form of Phosphorus is converted into the Inorganic form, which is recycled to Soil and Water.
• Soil and water will end up in sediments and rocks, which will again release Phosphorus by weathering. Thus, the Phosphorus cycle starts over.