The phosphorus cycle is the biogeochemical cycle which characterizes the transport and chemical transformation of phosphorus through the geosphere, hydrosphere and biosphere. Unlike many otherbiogeochemical cycles, the atmosphere does not play a significant role in the movement of phosphorus,since phosphorus and phosphorus-based compounds are typically solids at the normal ranges oftemperature and pressure found on Earth. Therefore most of the phosphorus remains within rock, sediments, sand, and the ocean floor, with a fraction in living biomass. Phosphorus moves among trophic levels in an ecosystem by plant growth, herbivory and carnivore