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  2. Human impact on the nitrogen cycle - Wikipedia

    en.wikipedia.org/wiki/Human_impact_on_the...

    Approximately 78% of Earth's atmosphere is N gas (N 2), which is an inert compound and biologically unavailable to most organisms.In order to be utilized in most biological processes, N 2 must be converted to reactive nitrogen (Nr), which includes inorganic reduced forms (NH 3 and NH 4 +), inorganic oxidized forms (NO, NO 2, HNO 3, N 2 O, and NO 3 −), and organic compounds (urea, amines, and ...

  3. Reactive nitrogen - Wikipedia

    en.wikipedia.org/wiki/Reactive_nitrogen

    Reactive nitrogen ("Nr"), also known as fixed nitrogen [1], refers to all forms of nitrogen present in the environment except for molecular nitrogen (N 2 ). [ 2 ] While nitrogen is an essential element for life on Earth, molecular nitrogen is comparatively unreactive, and must be converted to other chemical forms via nitrogen fixation before it ...

  4. Marine biogeochemical cycles - Wikipedia

    en.wikipedia.org/wiki/Marine_biogeochemical_cycles

    The nitrogen cycle is of particular interest to ecologists because nitrogen availability can affect the rate of key ecosystem processes, including primary production and decomposition. Human activities such as fossil fuel combustion, use of artificial nitrogen fertilizers, and release of nitrogen in wastewater have dramatically altered the ...

  5. Nitrogen cycle - Wikipedia

    en.wikipedia.org/wiki/Nitrogen_cycle

    Global cycling of reactive nitrogen [1] including industrial fertilizer production, [2] nitrogen fixed by natural ecosystems, [3] nitrogen fixed by oceans, [4] nitrogen fixed by agricultural crops, [5] NO x emitted by biomass burning, [6] NO x emitted from soil, [7] nitrogen fixed by lightning, [8] NH 3 emitted by terrestrial ecosystems, [9] deposition of nitrogen to terrestrial surfaces and ...

  6. Nitrification - Wikipedia

    en.wikipedia.org/wiki/Nitrification

    Nitrogen cycle. Nitrification is the biological oxidation of ammonia to nitrate via the intermediary nitrite.Nitrification is an important step in the nitrogen cycle in soil.The process of complete nitrification may occur through separate organisms [1] or entirely within one organism, as in comammox bacteria.

  7. Nitrogen hypoxia to execute a human: 'Bloodless, but it won't ...

    www.aol.com/news/nitrogen-hypoxia-execute-human...

    Because no person has ever been executed by inhaling pure nitrogen, how the state will carry out a nitrogen hypoxia execution remains unclear. Nitrogen hypoxia to execute a human: 'Bloodless, but ...

  8. Denitrification - Wikipedia

    en.wikipedia.org/wiki/Denitrification

    Since denitrification can remove NO 3 −, reducing its leaching to groundwater, it can be strategically used to treat sewage or animal residues of high nitrogen content. Denitrification can leak N 2 O, which is an ozone-depleting substance and a greenhouse gas that can have a considerable influence on global warming.

  9. Biological roles of the elements - Wikipedia

    en.wikipedia.org/wiki/Biological_roles_of_the...

    Can produce a variety of toxic effects in humans and other animals; also toxic to various microorganisms. [11] sodium: 11: 5: Essential to animals and plants in many ways, such as osmoregulation and transmission of nerve impulses. [11] Essential to energy metabolism of some bacteria, particularly extremophiles. [64]