1. Cody Guenzler, Period 3 Nitrogen Fixation Conversion of Nitrogen Assimilation Ammonification Nitrification Denitrification

2. Nitrogen Fixation  During this phase, the atmospheric nitrogen is processes to be use by plants.  Most of the fixation is done by free-living bacteria.  The bacteria combines gaseous nitrogen with hydrogen to produce ammonia which is then converted to make organic compounds.

3. Conversion of Nitrogen  The conversion of nitrogen contains four ways to convert nitrogen into more chemically reactive forms. 1.Biological fixation  Fixation from free-living bacteria 2.Industrial N-fixation  Great pressure, heat of 600 o C, and the use of an iron catalyst 3.Combustion of fossil fuels  Release of nitrogen oxides 4.Other processes  Lightning stikes

4. Assimilation  At this phase, plants absorb nitrogen from the soil through their roots in forms of either nitrate ions or ammonium ions.  All nitrogen that are collected by animals can be traced back to the eating of plants at some point in the food chain.

5. Ammonification  At this point, when a plant or animal dies, the initial form of the nitrogen is organic.  Bacteria converts the organic nitrogen from the remains back to ammonium through the process called mineralization.

6. Nitrification  This is the conversion of ammonia to nitrate by soil- living bacteria and other nitrifying bacteria.  In nitrification, ammonium is oxidized by bacteria which converts ammonia to nitrites.

7. Denitrification  Denitrification is the reduction of nitrates back to a large amount of inert nitrogen gas and completing the nitrogen cycle.