Phosphorus cycle

The major reservoir of phosphorus is rock.

In the rock phosphorus is bound to oxygen to form phosphate.

As water flows over rocks containing phosphorus(river water flows through) it erodes the surface and carries inorganic phosphate into the soil to be taken up by plants.

In plant cells, the phosphate is incorporated into biological molecules like phospholipids , protein and nucleic acid.

When animal feeds on the plant, phosphorus is transferred.

Phosphorus move along the food web as organism consume it and excretion of phosphorus also occur.

Decomposers will decompose waste and dead organisms ; release inorganic phosphate into the soil and water bodies.

Phosphorus released is used by terresterial and aquatic producers.

Phosphorus enter aquatic system as dissolved phosphate which is absorbed by algae and aquatic plants.

The algae and aquatic plants are then consumed by zooplanktons and inturn by fishes.

Some phosphate in the aquatic system returns to lamd via fish and invertebrates eaten by birds.

The faeces of bird contain phosphate which will absorbed by land plants.

Some phosphate can be carried by rivers into the ocean and remain in the seabed for millions of years.

In time, geological uplifting may expose these sediments and reenter the phosphorus cycle.

Phosphorus also enter the water ecosystem artificially through fertilisers.

Leaching of phosphate from agriculture areas increases the phosphate in aquatic habitats and stimulates algal growth.

The completion of phosphorus cycle is very slow because abiotic storage of phosphorus is in the form of rock.

diagram from: Phosphorus Cycle | Science | ShowMe