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A weather balloon rises in the atmosphere. The air in the atmosphere is mostly nitrogen molecules.
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Changing the Nitrogen Cycle, Changing the Planet

You can’t see air molecules. But if you could, you would see that most of them are made of two atoms of nitrogen bonded together. Nitrogen is not just in the sky. It is found all over the planet. It is in living things, air, water, and even animal poop. It travels between living and non-living parts of our planet via a process called the nitrogen cycle, one of the biogeochemical cycles.

As humans change the way we live on the planet, the way that nitrogen moves around the Earth also changes. Nitrogen atoms may be very small, but changes in the nitrogen cycle are having a large impact on our planet. Lakes are clogged with aquatic weeds. Dead zones have formed in areas of the oceans where animals can not survive. Air pollution that contains nitrogen makes the air quality worse. Greenhouse gases that contain nitrogen are becoming more common.

Read on to explore two examples of how humans affect the nitrogen cycle and how the changing nitrogen cycle affects humans and ecosystems.

Last modified May 7, 2007 by Lisa Gardiner.

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