phosphorus cycle



We explain what the phosphorus cycle is, its stages and importance for life. In addition, in which cases this cycle is altered.

Phosphorus circulates through ecosystems through living things and other factors.

What is the phosphorus cycle?

The phosphorus cycle or phosphoric cycle is the circuit that describes the movement of this chemical element within a given ecosystem. Phosphorus (P) is a non-metallic element, multivalent and highly reactive. It is located in the nature in various rocky sediments inorganic and in the body of living creatures, in which it is a vital part although on a small scale.

The phosphorus cycle is part of the biogeochemical cycles, in which the life and inorganic elements maintain a balance so that various chemical elements are recycled. This cycle would not be possible in quick terms without the Trophic chains of the different ecosystems.

However, compared to nitrogen cycles, the carbon or the Water, it is an extremely slow cycle, since phosphorus does not form volatile compounds that can move easily from water to water. atmosphere and from there back to earth, where it originates from.

The plants they also play a vital role in the fixation and transmission of phosphorus, as will be seen when we analyze its different stages.

Importance of the phosphorus cycle

Phosphorus is an element abundant in terrestrial minerals. Although it plays an indispensable role in living beings, it is little present in the body of living beings. It is part of the macromolecules of greater importance, such as the DNA, the RNA or the ATP (adenosine triphosphate).

Consequently, phosphorus is essential for obtaining energy at the biochemical level, as well as for the replication of the life and hereditary transmission. The phosphorus cycle is essential for life as we know it.

Stages of the phosphorus cycle

We can study the phosphorus cycle in the following stages:

  • Erosion and weathering. Phosphorus is abundant in terrestrial minerals, which are found on land or at the bottom of seas. The constant effects of rain, erosion wind and solar, as well as the accidental action of the mining of the human being allow these phosphorous reserves to rise to the surface and be transported to various ecosystems.
  • Fixation in plants and transmission to animals. Plants absorb phosphorus from soils and fix it in your body, both in the case of terrestrial plants, as well as algae and phytoplankton that absorbs it from the marine waters. From there it is transmitted to the animals that feed on the plants, in whose bodies it is also stored, and in the same way to the predators of sayings herbivorous animals and its predators, spreading throughout the food chain.
  • Return to the ground by decomposition. Animal excretions are rich in organic compounds that, being decomposed by the bacteria and others organisms from natural recycling, they return to being phosphates usable by plants, or transmissible to the soil. The same occurs when animals die and decompose, or when carcass left behind from hunting is decomposed. In all these cases, the phosphates return to the soil to be used by the plants or to continue to run off in rivers and rains towards the sea.
  • Return to the ground by sedimentation. Another route of return of phosphorus from the body of animals to the earth, (where it becomes part of sedimentary minerals) is much longer than that allowed by the action of animals, and has to do with the fossilization of their organic remains and the tectonic displacement of phosphorous reserves of organic origin towards the depths of the earth. But such geological uplifts can take thousands of years to occur.

Alterations in the phosphorus cycle

The phosphates in fertilizers alter the phosphorus cycle.

The phosphorus cycle can be greatly altered by human interference. On the one hand, the release of phosphorus by mining action can increase the presence of this material in the land surface, since its extraction by erosive natural ways would have taken thousands of years more.

On the other hand, the action of the fertilizers used in the farming (whether of natural or artificial origin) involves the injection of much more phosphates into the soil than it would normally receive. Such excess is washed away by rain or irrigation waters, running off into water reservoirs, rivers or the sea.

Due to the increase in phosphates and nitrogen, algae and microorganisms who take advantage of it. This process is called eutrophication, which consists of the excessive increase of nutrients in a aquatic ecosystem and that causes the trophic dynamics to be unbalanced, which generates an overpopulation of algae that compete with each other until they die en masse on the shore. When they decompose, they generate pollution and also increase the amounts of phosphorus circulating in seawater.

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