2. What is Nitrogen?  Nitrogen makes up about 78% of our atmosphere.  Nitrogen in the atmosphere it is mostly in the form of ______, which is a compound that plants and animals cannot use.  The process of converting nitrogen into compounds that can be used by plants and animals is called the ______________________. N2N2 Nitrogen Cycle

3. Why we care about nitrogen… Nitrogen is an essential component of _____________________. The building blocks of life. DNA, RNA and Proteins

4. How does atmospheric nitrogen (N 2 ) get changed into a form that can be used by most living organisms? By traveling through one of the ________ processes in the Nitrogen Cycle! Nitrogen Cycle (1) Nitrogen Fixation (2) Ammonification (3) Nitrification (4) Denitrification Four

5. Process 1: ___________________ is the process in which the N 2 compound in the atmosphere breaks and combines with other compounds. The nitrogen is _________ when it combines with ______________ or _______________. N N H N HH N2N2 Nitrogen Fixation “fixed” hydrogenoxygen Ammonia (NH 3 ) Nitrous Oxide (N 2 O)

6. Three ways to “fix” Nitrogen  Main process: Special ____________ convert the nitrogen gas (N 2 ) to ammonia (NH 3 ), which only ________ plants can use (peas, beans).  _________________ strikes convert N 2 to N 2 O or NO 3.  Industrial production. ____________ manipulation turns N 2 into NH 3 (Fertilizer) bacteria some Lightning Chemical

7. Process 2: _____________________ - After all the living organisms have used the ___________________, decomposer bacteria convert the nitrogen to _______________. N H H H Ammonification organic nitrogen ammonia Bacteria Ammonia Organic Nitrogen (proteins)

8. Process 3: _______________ is the process that converts ammonia (NH 3 ) into nitrites (NO 2 ) and nitrates (NO 3 ) which ____ plants _______ use. Note: Ammonia comes from ______ nitrogen fixation and ammonification How is it done? _____________________ N N N H H H O O O OO Nitrification most can both Bacteria!

9. Process 4: _______________: Process in which nitrogen compounds _____________________ into atmospheric nitrogen (N 2 or N 2 O). The main process is performed by _____________________ in the soil. It can also happen by _____________ fossil fuels. N2ON2O NO 3 N2N2 Denitrification convert back bacteria burning

10. Nitrogen in the air animal protein dead plants & animals urine & feces ammonia nitrites nitrates plant made protein decomposition by bacteria & fungi bacteria (nitrifying bacteria) nitrates absorbed denitrifying bacteria root nodules (containing nitrogen fixing bacteria) nitrogen fixing plant eg pea, clover bacteria

11. Human Impact  ___________________, releases toxic nitrogen compounds into the atmosphere.  ____________________________ release nitrous oxide into the atmosphere and introduce excess nitrogen into the environment.  Remove nitrogen from the soil when we mine it for nitrogen rich __________________________.  Discharge of ___________________________ releases excess nitrogen into the water ecosystems which disrupts the aquatic balance and kills fish. Combustion Commercial Fertilizers mineral deposits municipal sewage

12. Commercial Fertilizers  Are the ______ contributor of new nitrogen in the nitrogen cycle.  Added because nitrogen is a ________________ for plant growth.  Problems: hard to apply fertilizer and keep it in one area. Runoff, evaporation, etc.. So farmers apply about ___________________ as they need.  Extra nitrogen disrupts the ________________. #1 limiting factor twice as much food chain

13. Fritz Haber German Jew (1868-1934) Nobel prize 1918 for the synthesis of ammonia from nitrogen N 2 (g) + 3 H 2 (g) ⇌ 2 NH 3 (g)

14. The irony of Fritz Haber Gas warfare in WWI

15. Zyklon B

16. Dead zones

17. Ocean Dead Zones Double Every 10 Years

18. Dead zones