text: A number of different types of chemical cycles geochemical cycles occur on Earth. Biogeochemical cycles play an important role in sustaining the biosphere.
  Notable active chemical cycles on Earth include:
  * Carbon cycle – consisting of an atmospheric carbon cycle (and carbon dioxide cycle), terrestrial biological carbon cycle, oceanic carbon cycle and geological carbon cycle
  * Nitrogen cycle – which converts nitrogen between its forms through  fixation, ammonification, nitrification, and denitrification
  * Oxygen cycle and Ozone–oxygen cycle – a biogeochemical cycle  of circulating oxygen between the atmosphere, biosphere (the global sum of all ecosystems), and the lithosphere
  * Ozone-oxygen cycle – continually regenerates ozone in the atmosphere and converts ultraviolet radiation (UV) into heat
  * Water cycle – moves water continuously on, above and below the surface shifting between states of liquid, solution, ice and vapour
  * Methane cycle – moves methane between geological and biogeochemical sources and reactions in the atmosphere
  * Hydrogen cycle – a biogeochemical cycle brought about by a combination of biological and abiological processes
  * Phosphorus cycle – the movement of phosphorus through the lithosphere, hydrosphere, and biosphere
  * Sulfur cycle – a biogeochemical process resulting form the mineralization of organic sulfur, oxidation, reduction and incorporation into organic compounds
  * Carbonate–silicate cycle transforms silicate rocks to carbonate rocks by weathering and sedimentation and transforms carbonate rocks back into silicates by metamorphism and magmatism.
  * Rock cycle – switches rock between its three forms: sedimentary, metamorphic, and igneous
  * Mercury cycle – a biogeochemical process in which naturally occurring mercury is bioaccumulated before recombining with sulfur and returning to geological sources as sediments
  Other chemical cycles include hydrogen peroxide.