Phosphorus is one of the most important chemical elements involved in the development of living organisms. It is part of protoplasm and most animal and vegetable proteins. Phosphorus is vital for humans for the full development of organs and tissues, as well as for the normal functioning of the brain. No wonder Academician AE Fersman called it an element of life and thought.
The phosphorus cycle in the biosphere consists of several main links - these are rocks, soil, plants and animal organisms. The source of most phosphorus-containing compounds in nature is the mineral apatite, which contains from 5 to 36% phosphorus oxide. Apatite crystals are found in igneous rocks and in places of their contact with sedimentary rocks. Significant reserves of this mineral have been discovered in Brazil and Norway, and the largest deposit is located in the Khibiny (Kola Peninsula).
In the process of weathering, which occurs under the influence of atmospheric conditions, soil acids, living organisms, apatites are destroyed and involved in the biochemical cycle of phosphorus, encompassing the bio-, hydro- and lithosphere.
Plants absorb anions of phosphoric acid from dissolved phosphates and accumulate an element mainly in the generative organs - fruits and seeds. Different parts of the plants are consumed by animals and people, and the circulation of phosphorus continues.
In any animal organism, physiological processes constantly occur, associated with the breakdown, synthesis and other chemical transformations of phosphorus-containing compounds. In mammals, this element is found in the proteins of blood, milk, nervous, bone and brain tissues. It is also present in the composition of nucleic acids - compounds involved in the transmission of hereditary information. After the death of animal organisms, the phosphorus cycle closes - the element returns to the lithosphere, falling out of the biochemical cycle. Under certain conditions (for example, with a sharp change in climatic conditions, with fluctuations in salinity, temperature, water acidity, etc.), mass death of organisms and the accumulation of their remains on the seabed occurs . As a result, new deposits of phosphorus-containing rocks of sedimentary origin (for example, phosphorites) are formed. Over time, organogenic rocks - bioliths - become a new source of this element in the biogenic cycle.
As in all cycles of substances in nature, a person energetically intervenes in this process. Phosphorus and its compounds are used in metallurgy, the chemical industry, and in the production of detergents, matches, and pharmaceuticals. But the main consumer of phosphates is agriculture. This element is necessary for plants for full flowering and fruiting, it increases winter hardiness and is involved in the development of the root system. But on cultivated soils, the phosphorus supply is gradually depleted, and therefore there is a need for fertilizers, for the production of which all the same phosphorites and apatites are used.
Thus, new anthropogenic links — industry and agriculture — are included in the phosphorus cycle. Human activities are aimed at increasing the concentration of this element in the environment. This phenomenon, called by scientists the phosphatization of land, occurs due to the seafood catch and the extraction of phosphorus-containing minerals with subsequent use in various sectors of the agricultural complex. The most intensive phosphatization develops in industrially developed regions with a high population density. In sparsely populated areas and in areas of apatite and phosphorite mining, on the contrary, dephosphatization is observed.