1. By: Ijeoma Odihe Chelseay Parks Andrew Nunn

2. Definition Nitrogen cycle: Biogeochemical cycle in which nitrogen is transported throughout the Earth. Makes up approximately 78-80% of the Earth’s atmosphere.

3. The Importance of Nitrogen: Why is it necessary? It is essential for the production of DNA and proteins. 80% of the Earth’s atmosphere is comprised of free nitr0gen. Some organisms can use nitrogen directly and some organisms can require oxygen in the form of an organic compound.

4. Five Main Steps Nitrogen fixation: Atmospheric nitrogen is converted to ammonia Nitrification: Bacteria convert ammonia into nitrates. Assimilation: plant roots absorb ammonia, ammonium ions, or nitrates to make substances required for life. Ammonification: Decomposing bacteria convert all of the dead nitrogen rich organisms into ammonia and ammonium ions. Denitrification: conversion of nitrate ions into gas to be released into the atmosphere

5. Human Intervention Fossil fuel burning releases nitric oxide Nitrous oxide gas, greenhouse gas, is derived from livestock in fertilizer Removal of nitrogen along with plants Runoff and municipal waste induces eutrophication

6. Eutrophication Increase in concentration of chemical nutrients

7. Pictures

8. References http://southcobbhs.typepad.com/calvarez/ http://images.google.com/imghp?hl=en&tab=wi&q=g oogle http://images.google.com/imghp?hl=en&tab=wi&q=g oogle Botkin & Keller Environmental Science: Sixth Edition Textbook