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: Nitrogen Fixation ___________________ 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: Ammonification _____________________ - 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: Nitrification _______________ 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: Denitrification _______________: 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 Cycle (4) D enitrification (1) Nitrogen Fixation (2) Ammonification Nitrates in Soil Organic nitrogen is converted to ammonia. N2N2 NH 3 NO 3 N2ON2O Ammonia is converted to nitrites and nitrates. (3) Nitrification

11. 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

12. 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

13. 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

14. CFA 1.What are the four main processes of the nitrogen cycle? 2.What is it called when bacteria convert nitrogen into ammonia? 3.What organism is required for every step of the nitrogen cycle?