The Nitrogen Cycle

1. The Nitrogen Cycle In Aquatic Systems

2. The Nitrogen Cycle

3. How does a fish convert nitrogen into forms that plants can use?

4. What is Nitrogen • Nitrogen is an element that makes up many compounds and makes up organic molecules called proteins and nucleic acids. • N2 can only be taken in by a few organisms even though it is plentiful in the atmosphere.

5. Nitrogen turns into Ammonia (NH3) • When these organisms die they decompose into Ammonia Gas NH3. Fish waste, urine are products by fish that add to the ammonia level and any other decaying matter in the tank. • When Ammonia contacts with water it turns into Ammonium Hydroxide which is toxic in large amounts to fish.

6. Step One: Nitrosomonas Bacteria or Beneficial Bacteria • There are microscopic beings called nitrifying bacteria.

7. What are nitrifying bacteria ? Their role in nature is that of decomposers of nitrogen compounds. When we set up a new tank, these bacteria only exist in very small numbers so tanks need to be cycled for at least 2 to 6 weeks. This will build up the beneficial bacteria in the tank.

8. Bacteria: Nitrosomonas • These bacteria “eat “ the ammonia and turn it into “nitrite” but this can also be harmful to your fish. • Having plants in your tank will help absorb these nitrites.

9. Turning Nitrites to Nitrates • Another type of Bacteria will eat the Nitrites and turn them into Nitrates. • These are less harmful to the fish.

10. Begin taking water tests • Each group will do one test. • A. pH • B. Nitrate • C. Nitrite • Please follow the directions for each test and record the ammonia levels. Match the level with the color test card and record your level.

11. Answer the following questions: Quick Review. • 1. What happens to the pH when ammonia builds up in the tank? Does it lower or raise the pH? • 2. What is the name of the beneficial bacteria that are in the tank that turns Ammonia Hydroxide into Nitrites? • 3. What is the solution to lowering the ammonia levels in the fish tank?