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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 ...
Nitrogen is a chemical element; it has symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System.
A biogeochemical cycle, or more generally a cycle of matter, [1] is the movement and transformation of chemical elements and compounds between living organisms, the atmosphere, and the Earth's crust. Major biogeochemical cycles include the carbon cycle, the nitrogen cycle and the water cycle. In each cycle, the chemical element or molecule is ...
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. The transformation of ammonia to ...
Nitrogen enters the ocean through precipitation, runoff, or as N 2 from the atmosphere. Nitrogen cannot be utilized by phytoplankton as N 2 so it must undergo nitrogen fixation which is performed predominantly by cyanobacteria. [82] Without supplies of fixed nitrogen entering the marine cycle, the fixed nitrogen would be used up in about 2000 ...
{{Information| |Description=Diagram of the nitrogen cycle in an aquarium. |Source=Own work, drawn in Sodipodi and Inkscape by Ilmari Karonen. |Date=2005-10-2 File usage The following 4 pages use this file:
An example chemical cycle, a schematic representation of a Nitrogen cycle on Earth. This process results in the continual recycling of nitrogen gas involving the ocean. Chemical cycling describes systems of repeated circulation of chemicals between other compounds, states and materials, and back to their original state, that occurs in space ...
There is much overlap between the terms for the biogeochemical cycle and nutrient cycle. Most textbooks integrate the two and seem to treat them as synonymous terms. [5] However, the terms often appear independently. The nutrient cycle is more often used in direct reference to the idea of an intra-system cycle, where an ecosystem functions as a ...