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  2. Hydrogen cycle - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_cycle

    The hydrogen cycle consists of hydrogen exchanges between biotic (living) and abiotic (non-living) sources and sinks of hydrogen-containing compounds. Hydrogen (H) is the most abundant element in the universe. [1] On Earth, common H-containing inorganic molecules include water (H 2 O), hydrogen gas (H 2), hydrogen sulfide (H 2 S), and ammonia ...

  3. Microbial metabolism - Wikipedia

    en.wikipedia.org/wiki/Microbial_metabolism

    Microbial metabolism is the means by which a microbe obtains the energy and nutrients (e.g. carbon) it needs to live and reproduce.Microbes use many different types of metabolic strategies and species can often be differentiated from each other based on metabolic characteristics.

  4. Autotroph - Wikipedia

    en.wikipedia.org/wiki/Autotroph

    The process of photosynthesis splits a water molecule (H 2 O), releasing oxygen (O 2) into the atmosphere, and reducing carbon dioxide (CO 2) to release the hydrogen atoms that fuel the metabolic process of primary production. Plants convert and store the energy of the photons into the chemical bonds of simple sugars during photosynthesis.

  5. Water splitting - Wikipedia

    en.wikipedia.org/wiki/Water_splitting

    Electrolysis of water is the decomposition of water (H 2 O) into oxygen (O 2) and hydrogen (H 2): [2] Water electrolysis ship Hydrogen Challenger. Production of hydrogen from water is energy intensive. Usually, the electricity consumed is more valuable than the hydrogen produced, so this method has not been widely used.

  6. Plant nutrients in soil - Wikipedia

    en.wikipedia.org/wiki/Plant_nutrients_in_soil

    Nutrients in the soil are taken up by the plant through its roots, and in particular its root hairs.To be taken up by a plant, a nutrient element must be located near the root surface; however, the supply of nutrients in contact with the root is rapidly depleted within a distance of ca. 2 mm. [14] There are three basic mechanisms whereby nutrient ions dissolved in the soil solution are brought ...

  7. Semiheavy water - Wikipedia

    en.wikipedia.org/wiki/Semiheavy_water

    Semiheavy water is the result of replacing one of the protium (normal hydrogen, 1 H) in normal water with deuterium (2 H; or less correctly, [1] D). [2] It exists whenever there is water with 1 H and 2 H in the mix. This is because hydrogen atoms (1,2 H) are rapidly exchanged between water molecules.

  8. Hydrogen-oxidizing bacteria - Wikipedia

    en.wikipedia.org/wiki/Hydrogen-oxidizing_bacteria

    Hydrogen is the most widespread element in the universe, representing around three-quarters of all atoms. [4] In the atmosphere , the concentration of molecular hydrogen (H 2 ) gas is about 0.5–0.6 ppm, and so it represents the second-most-abundant trace gas after methane . [ 3 ]

  9. Heterotroph - Wikipedia

    en.wikipedia.org/wiki/Heterotroph

    A heterotroph (/ ˈ h ɛ t ər ə ˌ t r oʊ f,-ˌ t r ɒ f /; [1] [2] from Ancient Greek ἕτερος (héteros) 'other' and τροφή (trophḗ) 'nutrition') is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are ...