The Phosphorus cycle
(a) Unlike the nitrogen and carbon cycles, the phosphorus cycle does not involve a gaseous phase. As a consequence, phosphorus tends to cycle more locally rather than entering into the world-wide cycling seen with nitrogen and carbon.(b) The ultimate source of phosphorous is phosphate minerals that make up rocks.
(c) The form in which phosphorus is available is as the phosphate ion (PO4 3–)
(d) Phosphorous is lost from ecosystems by erosion; e.g., The Grand Canyon, an impressive example of erosion in action. Phosphorous can be gained by ecosystems, sometimes significantly, particularly via the movement of animals.
(e) “After producers incorporate phosphorus into biological molecules, it is transferred back to the soil by the excretion of phosphate by animals and by the action of decomposers on detritus.”
(f) Note that phosphorus is transferred to (and between) terrestrial environments also by processes other than just bird pooping (i.e., guano) including the migration of various others animals such as salmon, which carry phosphorous from the sea back to their mother streams and on the way are eaten by such things as bears which, yes, do go on to poop in the woods:
(g) [Heterotrophs (animals) obtain their phosphorous from the plants they eat, although one type of heterotroph, the fungi, excel at taking up phosphorous and may form mutualistic symbiotic relationships with plant roots. These relationships are called mycorrhizae; the plant gets phosphate from the fungus and gives the fungus sugars in return.
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