Sample Solution

    The global phosphorus cycle is the movement of the nutrient phosphorus and its various forms, such as phosphate ions, through the biosphere. Phosphorus plays a critical role in all organisms as it helps build strong cell structures and functions as an energy molecule. It is also used to make proteins, fats, carbohydrates and DNA. The global phosphorus cycle includes both abiotic reservoirs (such as rocks and oceans) and biotic reservoirs (such as plants and animals).

Phosphorus moves between these reservoirs in different forms; for example, it can be released from rocks into rivers or lakes in soluble forms like phosphate ions. These ions are taken up by plants either directly from water or soil where they have been deposited. Plants transfer phosphorus to animals which eat them through their diet. Some of this phosphorous is returned to soils when animal waste decomposes; some is transferred back to the atmosphere when plants respire; some enters oceans when rivers deposit sediment at their mouths; eventually yet more returns to land masses when oceanic sediments are uplifted during tectonic activity. At each stage there may be losses due to leaching or being locked away within certain mineral deposits; however overall it remains relatively constant over time due mainly to Earth's continual geologic processes that redistribute minerals between land, air and sea on geological timescales of millions of years rather than human ones. Humans are having a significant effect on this cycle by mining rock phosphates faster than they can be replenished naturally, leading to shortages in many parts of the world that rely heavily on agriculture for food production. In addition, runoff from agricultural fields has resulted in high concentrations of phosphate entering both freshwater systems (rivers/lakes) and coastal areas which leads to algal blooms that cause oxygen depletion resulting in fish kills etc., thereby affecting marine ecosystems too. Finally humans have also created artificial environments such as sewage treatment works which take large amounts of Phosphorus out of circulation so that it no longer cycles naturally back into soils but instead has been removed permanently from our environment via wastewater discharge into seas/oceans - effectively ‘locking’ it away forever!