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The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheric, terrestrial, and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes.
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 ...
Nitrogen-15 (15 N) tracing is a technique to study the nitrogen cycle using the heavier, stable nitrogen isotope 15 N.Despite the different weights, 15 N is involved in the same chemical reactions as the more abundant 14 N and is therefore used to trace and quantify conversions of one nitrogen compound to another.
Nitrogen is a critical chemical element in both proteins and nucleic acids, and thus every living organism must metabolize nitrogen to survive. Only bacteria and Archaea are able to convert nitrogen gas (N 2 ) to and from soluble ionic compounds that other organisms can metabolize.
The nitrogen cycle describes the movement of the element from the air, ... Pure nitrogen as food additive is labelled in the European Union with the E number E941.
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 ...
Donald Trump mocked Canadian Prime Minister Justin Trudeau after his top minister’s surprise resignation following a clash on how to handle the president-elect’s looming tariffs.
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 ...