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REVIEW: Lesson Summary
Lesson Summary
Phosphate mining is one way humans alter the phosphorous cycle. Photo courtesy of Susan Drackett/Flickr.
Phosphate mining is one way humans alter the phosphorous cycle. Photo courtesy of Susan Drackett/Flickr.
- The circulation of important materials through Earth's spheres are known as biogeochemical cycles
- There are 4 major biogeochemical cycles of particular importance to planet Earth: the water, nitrogen, phosphorous, and carbon cycles
- Despite the fact that most of our atmosphere is composed of nitrogen, it is not in a form usable by organisms
- Nitrogen needs to be "fixed" in order to be used by plants and animals; this is done mainly by bacteria, but lightning and forest fires can fix nitrogen too
- Humans alter the nitrogen cycle mainly through the addition of fertilizers to agricultural fields
- Nutrient pollution, the addition of too much nitrogen and/or phosphorous to the environment, causes eutrophication
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Humans alter the phosphorous cycle mainly through phosphate mining. Phosphorous is mined for use in detergents and fertilizers
Last modified: Thursday, 7 October 2010, 9:03 AM