THE NITROGEN CYCLE

1. THE NITROGEN CYCLE

2. NITROGEN

3. 7 N 14.01 Nitrogen = building blocks NITROGEN QUICK FACTS We use nitrogen to build proteins We use it to build each piece of DNA It’s the #1 gas in the atmosphere – 78%

4. R.I.P. “Animal” R.I.P. “Plant” Air Live Plants Where do you find it? Live Animals Soil Animal Waste Dead Animals & Plants

5. Where else is it found? Oceans

6. Where else is it found? Fertilizers

7. Nitrogen always comes in pairs when in the air… … we call this atmospheric nitrogen (N2) Plants and animals CANNOT use N2 to get their nitrogen! REJECTED N2 REJECTED

8. Luckily there are some kinds of bacteria that can change the nitrogen in the air… into forms that plants can use Animals can then eat those plants so that we get our nitrogen as well! N2 Accepted! Usable Nitrogen Accepted! Bacteria… not to scale

9. Bacteria changing N2 into a form that can be used by plants is called… Nitrogen Fixation And any bacteria that does this we call… Nitrogen Fixing Bacteria (Creative, I know)

10. Nitrogen Fixing Bacteria Nitrogen fixing bacteria refers to any bacteria that combine nitrogen with oxygen or hydrogen to create useable nitrogen for plants or animals. Useable forms of nitrogen include… • Ammonia (NH4) • Nitrates (NO3) Rhizobium Bacteria

11. Nitrogen-Fixing Bacteria Nodules

12. Review the animation N2 Accepted! Usable Nitrogen Accepted! Bacteria… not to scale

13. Now review it in your notes N2 Accepted! Usable Nitrogen Accepted! Bacteria… not to scale

14. That’s it, we’re done, RIGHT? WRONG This is a cycle, remember?

15. EPISODE II THE NITROGEN CYCLE

16. Option A Let’s review - see if you can tell me where “Nitrogen Fixation” is taking place in the process below… Option D N2 Accepted! Option B Usable Nitrogen Option C Accepted! Bacteria… not to scale

17. R.I.P. “Plant” R.I.P. “Cow” So what next? Once the nitrogen goes into animals and plants how does it get out to complete the cycle? 1. Waste As animal waste and dead organisms are broken down by decomposers, their nitrogen is released back into the soil… 2. Death

18. Two things can happen from there… 1. It can be reabsorbed by plants 2. A second kind of bacteria can change the nitrogen back into N2 N2 Accepted!

19. The process where bacteria change usable nitrogen back into N2 is called… Denitrification And we call the bacteria that do this… Denitrifying Bacteria

20. R.I.P. “Plant” R.I.P. “Cow” We have a cycle… N2 Accepted! Usable Nitrogen N2 Accepted! Bacteria… not to scale

21. N2 N2 N2 Atmosphere Consumption Waste Nitrogen Fixation Denitrification Death Root Absorption Nitrogen Fixing Bacteria Decomposers Denitrifying Bacteria Cycle within a cycle

22. So how are humans affecting the Nitrogen Cycle? 1. Fertilizer Overload

24. So how are humans affecting the Nitrogen Cycle? 1. Fertilizer Overload 2. Air Pollutants

26. So how are humans affecting the Nitrogen Cycle? 1. Fertilizer Overload 2. Air Pollutants 3. Greenhouse Gases

29. What else should I know about the nitrogen cycle? Legumes Lightning LIGHTNINGED!

30. What else should I know about the nitrogen cycle? Legumes Lightning

31. IT’S OVER! What else should I know about the nitrogen cycle? Legumes Lightning

32. N2 N2 N2 Atmosphere Consumption Waste Nitrogen Fixation Denitrification Death Root Absorption Nitrogen Fixing Bacteria Decomposers Denitrifying Bacteria Cycle within a cycle