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  2. Oxygen cycle - Wikipedia

    en.wikipedia.org/wiki/Oxygen_cycle

    Oxygen cycle refers to the movement of oxygen through the atmosphere (air), biosphere (plants and animals) and the lithosphere (the Earth’s crust). The oxygen cycle demonstrates how free oxygen is made available in each of these regions, as well as how it is used. The oxygen cycle is the biogeochemical cycle of oxygen atoms between different ...

  3. Ozone–oxygen cycle - Wikipedia

    en.wikipedia.org/wiki/Ozone–oxygen_cycle

    The ozone– oxygen cycle is the process by which ozone is continually regenerated in Earth 's stratosphere, converting ultraviolet radiation (UV) into heat. In 1930 Sydney Chapman resolved the chemistry involved. The process is commonly called the Chapman cycle by atmospheric scientists. Most of the ozone production occurs in the tropical ...

  4. Ozone layer - Wikipedia

    en.wikipedia.org/wiki/Ozone_layer

    Ozone-oxygen cycle in the ozone layer. The photochemical mechanisms that give rise to the ozone layer were discovered by the British physicist Sydney Chapman in 1930. Ozone in the Earth's stratosphere is created by ultraviolet light striking ordinary oxygen molecules containing two oxygen atoms (O 2), splitting them into individual oxygen atoms (atomic oxygen); the atomic oxygen then combines ...

  5. Oxygen - Wikipedia

    en.wikipedia.org/wiki/Oxygen

    Oxygen is a chemical element; it has symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is the most abundant element in Earth's crust, and after hydrogen and helium, it ...

  6. Geological history of oxygen - Wikipedia

    en.wikipedia.org/wiki/Geological_history_of_oxygen

    Oxygen began building up in the atmosphere at approximately 1.85 Ga. At current rates of primary production, today's concentration of oxygen could be produced by photosynthetic organisms in 2,000 years. [4] In the absence of plants, the rate of oxygen production by photosynthesis was slower in the Precambrian, and the concentrations of O 2 ...

  7. Ozone depletion - Wikipedia

    en.wikipedia.org/wiki/Ozone_depletion

    The ozone cycle. Three forms (or allotropes) of oxygen are involved in the ozone-oxygen cycle: oxygen atoms (O or atomic oxygen), oxygen gas (O 2 or diatomic oxygen), and ozone gas (O 3 or triatomic oxygen). [15] Ozone is formed in the stratosphere when oxygen gas molecules photodissociate after absorbing UVC photons. This converts a single O

  8. Ozone - Wikipedia

    en.wikipedia.org/wiki/Ozone

    Ozone (/ ˈoʊzoʊn /) (or trioxygen) is an inorganic molecule with the chemical formula O. 3. It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope O. 2, breaking down in the lower atmosphere to O.

  9. Chemical cycling - Wikipedia

    en.wikipedia.org/wiki/Chemical_cycling

    This process results in the continual recycling of nitrogen gas involving the ocean. Chemical cycling describes systems of repeated circulation of chemicals between other compounds, states and materials, and back to their original state, that occurs in space, and on many objects in space including the Earth. Active chemical cycling is known to ...