Nitrogen Cycle

Nitrogen Cycle

By: Joshua Miller

The Nitrogen Cycle is when nitrogen moves between the atmosphere, biosphere, and geosphere in different forms.  It is a biogeochemical cycle by which nitrogen is converted into various chemical

forms as it circulates. The conversion of nitrogen can be carried out through both biological and physical processes.  Even though most of the air we breathe is N2, most of the nitrogen in the air is not available for use by organisms because it is relatively unreactive; whereas, organisms need reactive nitrogen to be able to bring it into cells.  For plants and animals to be able to use nitrogen, N2 gas is first converted to a more chemically available form   

There are five main processes that cycle nitrogen through the geosphere, atmosphere, and biosphere.  They are nitrogen fixation,  nitrogen uptake through organismal growth, nitrogen mineralization through decay, nitrification, and denitrification.    Microorganisms like bacteria play a major role in all of the main nitrogen transformations.  

Since atmospheric nitrogen has limited availability for biological use, usable nitrogen is scarce in many types of ecosystems.  Ecologists find the nitrogen cycle interesting because nitrogen availability can affect the rate of certain ecosystem processes such as decomposition.  The human activities of fossil fuel combustion, use of artificial nitrogen fertilizers, and the release of nitrogen in wastewater have dramatically altered the global nitrogen cycle.  

In summary, most nitrogen in the air cannot be used by organisms because it is unreactice.  For plants and animals to be able to use nitrogen, it must first be converted to a more chemically available form. I found it interesting, but I am not surprised, that human activities can affect the way the nitrogen cycle works.  

https://en.wikipedia.org/wiki/Nitrogen_cycle

http://www.visionlearning.com/en/library/Earth-Science/6/The-Nitrogen-Cycle/98