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The oxygen cycle is the biogeochemical cycle of oxygen atoms between different oxidation states in ions, oxides, and molecules through redox reactions within and between the spheres/reservoirs of the planet Earth. [ 1] The word oxygen in the literature typically refers to the most common oxygen allotrope, elemental/diatomic oxygen (O 2 ), as it ...
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 ...
Photosynthesis ( / ˌfoʊtəˈsɪnθəsɪs / FOH-tə-SINTH-ə-sis) [ 1] is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabolism.
O. have also been characterized, all short-lived. The longest-lived radioisotope is 15. O. with a half-life of 122.266 (43) s, while the shortest-lived isotope is the unbound 11. O. with a half-life of 198 (12) yoctoseconds, though half-lives have not been measured for the unbound heavy isotopes 27. O. and 28.
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 ...
In the context of nutrition, a mineral is a chemical element. Some "minerals" are essential for life, but most are not. [ 1][ 2][ 3] Minerals are one of the four groups of essential nutrients; the others are vitamins, essential fatty acids, and essential amino acids. [ 4] The five major minerals in the human body are calcium, phosphorus ...
Energy flow is the flow of energy through living things within an ecosystem. [ 1] All living organisms can be organized into producers and consumers, and those producers and consumers can further be organized into a food chain. [ 2][ 3] Each of the levels within the food chain is a trophic level. [ 1] In order to more efficiently show the ...
Scientists have discovered a new source of oxygen on the planet, originating from metal “batteries” deep beneath the Pacific Ocean. The “dark oxygen” phenomenon was observed at depths of ...