The carbon cycle, one of Earth's biogeochemical cycles.
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Biogeochemical Cycles

As a part of biogeochemical cycles, certain elements move through both living and non-living components of the Earth system. The living parts of the Earth system comprise the biosphere, while the non-living parts of the Earth include the hydrosphere, atmosphere, cryosphere, and geosphere. The same individual elements are recycled over and over in different parts of the Earth through biogeochemical cycles.

For example, carbon may be taken from the air (atmosphere) into the ocean surface (hydrosphere) where it is utilized by photosynthesizing plankton (biosphere). Carbon is also stored long-term in rocks (geosphere) and fossil fuels like oil, coal, and natural gas (biosphere). This long-term storage that sequesters an element from the rest of the cycle for some amount of time is called a “sink”. When fossil fuels are burned, carbon that had been sequestered underground is sent into the air (atmosphere) as carbon dioxide, a greenhouse gas.

All chemical elements that are found in living things are a part of biogeochemical cycles, the most common of these being carbon and nitrogen.

Find out more about two common biogeochemical cycles!

In recent decades these biogeochemical cycles have been changing because of how humans are changing the biosphere (see links below). Less forests, more factories and cars that burn fossil fuels - these changes to biogeochemical cycles are causing more greenhouse gases in our atmosphere and, thus, more global warming.

Last modified May 7, 2007 by Lisa Gardiner.

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