Geography4Kids.com Home Link to Earth Structure Link to Biosphere Link to Atmosphere Link to Hydrosphere Link to Nutrient Cycles Link to Activities
Geography4Kids.comBiogeochemical (BGC) Cycles
 

The Nitrogen Cycle

Nitrogen (N) is an element like carbon. All creatures need nitrogen to survive. There are huge amounts of nitrogen gas in the atmosphere, but most animals and plants have no way of using it. It needs to be fixed (put into a biologically useful compound). After it is fixed, it can then start to move through the cycles and organisms in an ecosystem.

Where Can You Find It?

Let's start with the main sources of nitrogen. Nitrogen gas is the most abundant element in our atmosphere. The other main source of nitrogen is in the nitrates of soil. The nitrogen in the atmosphere cannot be used while the nitrates in the soil can be used by plants. Nitrogen can be converted into useful nitrate compounds by bacteria, algae, and even lightning. Once in the soil, the nitrogen becomes biologically accessible.

Borrowing Nitrogen

Plants are the main users of nitrogen in the soil. They are able to take in the nitrates through their root system. Once inside the plant, the nitrates are used in organic compound that let the plant survive. Organic compounds have carbon atoms. Those compounds might be proteins, enzymes, or nucleic acids.

Once the plants have converted the nitrogen, the element can be returned to the soil or taken up by animals. Herbivores eat plants and convert many of the amino acids into new proteins. Omnivores that eat both plants and animals are able to take in the nitrogen rich compounds as well. The nitrogen compounds are only borrowed. Nitrogen atoms are returned to the soil in poop and dead organisms. Once in the soil, the whole process can start again.

Return to Top of Page

RELATED LINKS
- Chem4Kids: Biochemistry
- Chem4Kids: Chemical Reactions
- Chem4Kids: Environmental Chemistry
- Biology4Kids: Passive Transport
- Biology4Kids: Digestive System
- Biology4Kids: Respiratory System
- Biology4Kids: Plants
- Cosmos4Kids: Earth

- NASA: Kennedy Space Center
- NASA: Goddard Spaceflight Center

 
- Overview
- Energy
- Carbon
- Water
- Oxygen
> Nitrogen
- Iron
- Phosphorus
- Rocks

MORE EARTH SCIENCE TOPICS


* The custom search only looks at Rader's sites.


Link to Cosmos4Kids.com Link to Biology4Kids.com Link to Chem4Kids.com Link to Geography4Kids.com Link to Physics4Kids.com Link to NumberNut.com Rader Network Side Navigation
 

Go to Help Page Go for site help or a list of earth science topics at the site map!
©copyright 1997-2013 Andrew Rader Studios, All rights reserved.
Current Page: Geography4Kids.com | Physical Geography | BGC Cycles | Nitrogen Cycle

 

** Andrew Rader Studios does not monitor or review the content available at these web sites. They are paid advertisements and neither partners nor recommended web sites.