1. Nitrogen Cycle

2. Geochemical cycles are beautiful and wonderfully complex. One of the most dynamic of these is the Nitrogen cycle. Describe the cycle and how Nitrogen is stored in the ecosystem. Be sure to include in your description how Nitrogen changes form to become available for plant usage and its importance in biological systems.

4. Some Uses Production of organic molecules by plants and animals. Ex: amino acids, proteins, nucleic acids Plant nutrient- major one for vegetative growth.

5. Amino acids

6. Storage Sites Major area is the atmosphere Organic matter in the soil and in the oceans

7. The Forms of Nitrogen in Storage

8. The Cycle Abundance is “tricky” because it is the most limiting nutrient for plant growth Plants take up in the form (s) –NH 4 + ammonium (to much is toxic) –NO 3 - nitrate (soil solutions that are prone to leach)

9. The Cycle Transformations to Usable Forms Mineralization Organic matter --- decomposers--- (bacteria, actinomycetes, and fungi) ---ammonia(NH 4 + ) and (NH 4 + ) ammonium salts

10. Transformations cont. Micelle fixation NH 4 + absorbed onto clay particles released from colloids by cat-ion exchange Nitrification Nitrosomonas autotropic bacteria converts ammonia to nitrite NH 3 + --- NO 2 - Nitrobactor autotropic bacteria convert Nitrite to Nitrate NO 2 - --- NO 3 -

11. The Cycle Nitrogen returns to environment –Leaching through soil profile and the into bodies of water –Nitrogen in Soil and Water goes through denitrification - Anaerobic (without oxygen) process NO 3 - N 2(g) reduction N 2 O (g)

12. The Nitrogen Cycle

13. Bibliography http://www.science.duq.edu/esm/Course_ Material/ESM552/Notes/Chapter2/GIFS/fig 2_8.GIFhttp://www.science.duq.edu/esm/Course_ Material/ESM552/Notes/Chapter2/GIFS/fig 2_8.GIF www.lloydminsterheavyoil.com/ buildheavy.htm bouman.chem.georgetown.edu/.../ nitrogen.4.jpeg

14. www.edunet.tn/.../la%20liaison/ la%20liaison.htmwww.edunet.tn/.../la%20liaison/ la%20liaison.htm www.cmbi.kun.nl/.../infopages/ amino- acids.shtmlwww.cmbi.kun.nl/.../infopages/ amino- acids.shtml