Found organically in the form of the phosphate ion (PO 4 3-).
Figure 1. The phosphorus cycle. Phosphate is taken up by plants from soils, utilized by animals that consume plants, and returned to soils as organic residues decay in soils (Figure 1) . Much of the phosphate used by living organisms becomes incorporated into organic compounds. Humans can alter the phosphorus cycle in many ways, including in the cutting of tropical rain forests and through the use of agricultural fertilizers. Rainforest ecosystems are supported primarily through the recycling of nutrients, with little or no nutrient reserves in their soils. This nutrient cycle begins with photosynthesis, the process by which plants, algae, and some bacteria use energy from sunlight to combine carbon dioxide (CO 2) from the atmosphere and water to form sugars, starch, fats, proteins, and other compounds that they use to build cells or store as food. The Phosphorus Cycle. The phosphorus cycle differs from many other biogeochemical cycles because it does not involve the atmosphere in any significant way (although there is some evidnece of an atmospheric component in the form of PH3). Phosphorus and phosphorus-based compounds are usually solids at normal temperatures and pressuresfound on Earth, and any phosphorus in the atmosphere is usually only present in the form of dust particles. Phosphorus-which is an essential nutrient-is usually found in the form of the phosphate ions (PO 4 3- and HPO 4 2-). It is an important component of nucleic acid molecules (DNA & RNA) and of the cellular energy carrier ATP. The nutrient cycle describes the use, movement, and recycling of nutrients in the environment. Valuable elements such as carbon, oxygen, hydrogen, phosphorus, and nitrogen are essential to life and must be recycled in order for organisms to exist. In the phosphorus cycle, phosphorus is circulated mainly through soil, rocks, water, and living organisms. Phosphorus is found organically in the form of the phosphate ion (PO 4 3-). Phosphorus is added to soil and water by runoff resulting from the weathering of rocks that contain phosphates. Phosphorus (P) is an essential element classified as a macronutrient because of the relatively large amounts of P required by plants. Phosphorus is one of the three nutrients generally added to soils in fertilizers. One of the main roles of P in living organisms is in the transfer of energy.
http://www.extension.umn.edu/agriculture/nutrient-management/phosphorus/the-nature-of-phosphorus/ http://enviroliteracy.org/air-climate-weather/biogeochemical-cycles/phosphorus-cycle/ http://www.wisegeek.org/what-is-the-nutrient-cycle.htm http://sci.waikato.ac.nz/farm/content/nutrientcycling.html http://sci.waikato.ac.nz/farm/content/nutrientcycling.html http://biology.about.com/od/ecology/ss/nutrient-cycle.htm http://biology.about.com/od/ecology/ss/nutrient-cycle.htm http://www.extension.umn.edu/agriculture/nutrient-management/phosphorus/the-nature-of-phosphorus/
what are the nutrients in the phosphorus cycle