The Phosphorus Cycle (including human influences)

Understanding the Phosphorus Cycle

The phosphorus cycle is a biogeochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere.
Unlike other major biogeochemical cycles, the phosphorus cycle does not include a gas phase, passing primarily through rocks, soil, water, and living organisms.
Phosphorus is an essential nutrient for plants and animals in the form of phosphates, required for cell membrane structure, energy transfer (ATP), and nucleic acids (DNA and RNA).

Components of the Phosphorus Cycle

Weathering of rocks: The phosphorus cycle begins with the weathering or erosion of phosphate-laden rocks, which releases phosphates into the soil and water.
Uptake by plants and animals: Plants absorb these phosphates from soil or water, and then animals obtain phosphorus by eating plants or plant-eating animals.
Decomposition: When plants and animals die and decompose, or when animals excrete waste, phosphorus returns to the soil and water, potentially to be used again by plants.
Sedimentation: Over time, phosphorus in water bodies can slowly sink and become part of rock formations, an occurrence referred to as sedimentation. This phosphorus can eventually be brought back to the surface through tectonic activity, continuing the cycle.

Human Influence on the Phosphorus Cycle

Mining and Fertilisers: The mining of phosphorus for the production of artificial fertilisers has lead to an increase in the amount of phosphorus entering ecosystems, heavily influencing the natural phosphorus cycle.
Eutrophication: The excess phosphorus from fertilisers can cause eutrophication in water bodies, characterised by algal bloom, oxygen depletion, and adverse effects on aquatic life.
Detergents: Phosphates are also used in many cleaning products. When these enter water bodies, they act as a pollutant, also increasing the instances and severity of eutrophication.
Animal Feeds: High phosphate levels can be found in animal feed, which, when excreted as waste, can further contribute to the level of phosphates in the soil and water.

By revising these points, you will have a clear understanding of the nature of the phosphorus cycle, its components, and how human activity has significantly influenced this biogeochemical cycle.