In addition to water, carbon, nitrogen and oxygen, phosphorus is also important to living things. This element is, for example, part of hereditary material and from ATP energy molecules.
In some respects, the phosphorus cycle is simpler than the carbon and nitrogen cycles, as there are not many gaseous phosphorus compounds and therefore no passage through the atmosphere. Another reason for the simplicity of the phosphorus cycle is that there is only one phosphorus compound really important to living things: the phosphate ion.
Plants obtain phosphorus from the environment by absorbing the phosphates dissolved in water and soil. Animals get phosphates in water and food.
Decomposition returns the phosphorus that was part of organic matter to soil or water. Hence, part of it is dragged by the rains to the lakes and seas, where it ends up being incorporated into the rocks. In this case, phosphorus will only return to ecosystems much later, when these rocks rise as a result of geological processes and, on the surface, are decomposed and turned into soil.
Thus, there are two phosphorus cycles that happen at very different time scales. Part of the element recycles locally between soil, plants, consumers and decomposers in a relatively short time scale, which we may call “Ecological time cycle”. Another part of the environmental phosphorus settles and is incorporated into the rocks; its cycle involves a much longer time scale, which can be called “Geological time cycle”.