Nitrogen cycle

Nitrogen cycle

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  NITROGEN CYCLE Samarth singh 8th-E Kviit
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  Nitro • an essentialpart of the amino acids. It is a basic element of life. Cyclegen n + es‘‘nitre forming’’ • composes about four-fifths (78.03 percent) by volume of the atmosphere. •in the form of protein is an important constituent of animal tissue. • is an important element in plant nutrition.•is inert and serves as a diluent for oxygen in burning and respiration processes.
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  Nitrogen Cycle • naturalcyclic process in the course of which atmospheric nitrogen enters the soil and becomes part of living organisms
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  Importance of NitrogenCycle • essential to living organisms and its availability plays a crucial role in the organization and functioning of the world's ecosystems • key factor controlling the nature and diversity of plant life • vital ecological processes such as plant productivity and the cycling of carbon and soil minerals
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  Steps of NitrogenCycle • Nitrogen Fixation • Nitrogen Assimilation • Ammonification • Nitrification • Denitrification
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  Nitrogen Fixation • nitrogengas is converted into inorganic nitrogen compounds. It is mostly (90 percent) accomplished by free-living, nitrogen-fixing bacteria.
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  Nitrogen-Fixing Bacteria • symbioticbacteria living on the roots of plants (mostly legumes and alders) • cyanobacteria (formerly known as blue- green algae) • archaebacteria (also known as archaea) in deep-sea hydrothermal vents
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  Nitrogen Fixation byHaber-Bosch Process • method of directly synthesizing ammonia from hydrogen and nitrogen, developed by the German physical chemist Fritz Haber.
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  Nitrogen Fixation byLightning • The high energies provided by lightning and cosmic radiation serve to combine atmospheric nitrogen and oxygen into nitrates, which are carried to the Earth’s surface in precipitation.
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  Steps of NitrogenCycle • Nitrogen Fixation • Nitrogen Assimilation • Ammonification • Nitrification • Denitrification
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  Nitrogen Assimilation • areassimilation of nitrates and ammonia resulting from nitrogen fixation into the specific tissue compounds of algae and higher plants. Animals then ingest these algae and plants, converting them into their own body compounds.
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  Steps of NitrogenCycle • Nitrogen Fixation • Nitrogen Assimilation • Ammonification • Nitrification • Denitrification
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  Ammonification • The remainsof all living things—and their waste products—are decomposed by microorganisms which yields ammonia.
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  Steps of NitrogenCycle • Nitrogen Fixation • Nitrogen Assimilation • Ammonification • Nitrification • Denitrification
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  Nitrification • a processcarried out by nitrifying bacteria, transforms soil ammonia into nitrates, which plants can incorporate into their own tissues.
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  Steps of NitrogenCycle • Nitrogen Fixation • Nitrogen Assimilation • Ammonification • Nitrification • Denitrification
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  Denitrification • The processwhere nitrates are metabolized by denitrifying bacteria to free nitrogen and returned to the atmosphere
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  Human Intrusion andIts Effects Declination of nitrogen in the soil • cultivation of croplands • harvesting of crops • cutting of forests
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  Human Intrusion andIts Effects Over supply of Nitrogen • the production and use of nitrogen fertilizers • burning of fossil fuels in automobiles, power generation plants, and industries
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  Human Intrusion andIts Effects Over supply of Nitrogen • the leaching of nitrogen from over fertilized croplands, • animal wastes and sewage
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  Effects of OverSupply of Nitrogen • substantial acidification of soils and of the waters of streams and lakes • acid rain • Increased global concentrations of nitrous oxide (N2O), a potent greenhouse gas,
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  Effects of OverSupply of Nitrogen • stratospheric ozone depletion • greatly increased transport of nitrogen by rivers into estuaries and coastal waters where it is a major pollutant.
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  References • http://www.bbc.co.uk/schools/gcsebitesize/science/21c/food/naturalp olymersrev3.shtml • http://www.epa.gov/owow/watershed/wacademy/acad2000/nitroabstr. html •Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved. • nitrogen cycle. (2010). In Encyclopædia Britannica. Retrieved September 02, 2010, from Encyclopædia Britannica Online: http://www.britannica.com/EBchecked/topic/416271/nitrogen- cycle • Haber-Bosch process. (2010). Encyclopædia Britannica. Encyclopaedia Britannica Ultimate Reference Suite. Chicago: Encyclopædia Britannica.