nitrogen cycle

Examples of nitrogen cycle in the following topics:

• The Nitrogen Cycle

  • The nitrogen cycle is the process by which nitrogen is converted from organic to inorganic forms; many steps are performed by microbes.
  • The nitrogen cycle describes the conversion of nitrogen between different chemical forms.
  • Nitrogen is essential for the formation of amino acids and nucleotides.
  • It can either be cycled back into a plant usable form through nitrification or returned to the atmosphere through de-nitrification.
  • Describe the nitrogen cycle and how it is affected by human activity

• The Nitrogen Cycle

  • Nitrogen is cycled through the earth via the multi-step process of nitrogen fixation, which is carried out by bacteria.
  • Cyanobacteria are able to use inorganic sources of nitrogen to "fix" nitrogen.
  • The nitrogen that enters living systems by nitrogen fixation is successively converted from organic nitrogen back into nitrogen gas by bacteria .
  • A similar process occurs in the marine nitrogen cycle, where the ammonification, nitrification, and denitrification processes are performed by marine bacteria.
  • Although the movement of nitrogen from rock directly into living systems has been traditionally seen as insignificant compared with nitrogen fixed from the atmosphere, a recent study showed that this process may indeed be significant and should be included in any study of the global nitrogen cycle.

• Nitrospirae and Deferribacter

  • Nitrospirae is a phylum of bacteria; some nitrospirae species perform important functions in the nitrogen cycle.
  • Some nitrospirae species perform important functions in the Nitrogen Cycle :
  • The Nitrogen Cycle describes the changes in nitrogenous compounds in the environment.
  • Because many of them are toxic, it is important to know something about this cycle.
  • Luckily, these compounds are converted to less and less toxic forms through this Nitrogen Cycle.

• The Role of Prokaryotes in Ecosystems

  • Prokaryotes play vital roles in the movement of carbon dioxide and nitrogen in the carbon and nitrogen cycles.
  • Prokaryotes play many roles in the environments they occupy, but the roles they play in the carbon and nitrogen cycles are vital to life on earth.
  • Prokaryotes play an important role in the carbon cycle .
  • In this case, the cycle is based on one-carbon compounds.
  • As a macronutrient in nature, it is recycled from organic compounds to ammonia, ammonium ions, nitrate, nitrite, and nitrogen gas by myriad processes, many of which are carried out solely by prokaryotes; they are key to the nitrogen cycle .

• Nitrogen Fixation: Root and Bacteria Interactions

  • Atmospheric nitrogen, which is the diatomic molecule N2, or dinitrogen, is the largest pool of nitrogen in terrestrial ecosystems.
  • However, nitrogen can be "fixed."
  • Through symbiotic nitrogen fixation, the plant benefits from using an endless source of nitrogen from the atmosphere.
  • Schematic representation of the nitrogen cycle.
  • Abiotic nitrogen fixation has been omitted.

• Nitrogenase and Nitrogen Fixation

  • Nitrogen fixation also refers to other biological conversions of nitrogen, such as its conversion to nitrogen dioxide.
  • Nitrogen fixation is a process by which nitrogen (N2) in the atmosphere is converted into ammonia (NH3).
  • Atmospheric nitrogen or elemental nitrogen (N2) is relatively inert: it does not easily react with other chemicals to form new compounds.
  • Microorganisms that fix nitrogen are bacteria called diazotrophs.
  • Biological nitrogen fixation (BNF) occurs when atmospheric nitrogen is converted to ammonia by an enzyme called nitrogenase.

• Sources and Sinks of Essential Elements

  • Most important substances on Earth, such as oxygen, nitrogen, and water undergo turnover or cycling through both the biotic (living) and abiotic (geological, atmospheric, and hydrologic) compartments of the Earth.
  • Ecosystems hinge on biogeochemical cycles.
  • The nitrogen cycle, the phosphorous cycle, the sulfur cycle, and the carbon cycle all involve assimilation of these nutrients into living things.
  • The atmosphere is considered a reservoir for nitrogen.
  • This flow from abiotic to biotic compartments of the Earth is typical of biogeochemical cycles.

• Role of Microbes in Biogeochemical Cycling

  • Nutrients move through the ecosystem in biogeochemical cycles.
  • A biogeochemical cycle is a pathway by which a chemical element (such as carbon or nitrogen) circulates through the biotic (living) and the abiotic (non-living) factors of an ecosystem.
  • A good example of a molecule that is cycled within an ecosystem is water, which is always recycled through the water cycle.
  • The key collective metabolic processes of microbes (including nitrogen fixation, carbon fixation, methane metabolism, and sulfur metabolism) effectively control global biogeochemical cycling.
  • Consequently, chemical processing of nitrogen (or nitrogen fixation) is necessary to convert gaseous nitrogen into forms that living organisms can use.

• Properties of Nitrogen

  • Nitrogen compounds were well known during the Middle Ages.
  • Nitrogen is a chemical element with symbol N and atomic number 7.
  • The nitrogen cycle describes the movement of the element from the air into the biosphere and organic compounds and back into the atmosphere.
  • Nitrogen is a nonmetal with an electronegativity of 3.04.
  • The triple bond in molecular nitrogen (N2) is one of the strongest known.

• Nitrogenous Waste in Terrestrial Animals: The Urea Cycle

  • It is the main nitrogen-containing substance in the urine of mammals.
  • The body uses it in many processes, the most notable one being nitrogen excretion.
  • Urea is widely used in fertilizers as a convenient source of nitrogen.
  • Hence, the urea cycle is also referred to as the ornithine cycle.
  • The enzyme ornithine transcarbamylase catalyzes a key step in the urea cycle.