The Nitrogen Cycle Nitrogen, like water, is recycled through ecosystems over and over....

1. The Nitrogen Cycle Nitrogen, like water, is recycled through ecosystems over and over....

2. Take a deep breath! 78% of the air you just breathed in is made up of nitrogen gas. Your body requires nitrogen to build proteins, amino acids, and DNA, but your body cannot use the nitrogen gas you just breathed in. Look at the diagram on page 52 of your textbook to see where consumers like us (and the sheep in the diagram!) get nitrogen.

3. The Nitrogen Cycle Nitrogen  a necessary building block of living organisms used to make proteins, amino acids, and DNA found in atmosphere  78% of atmosphere is free nitrogen gas (N2)  cannot be used by most organisms nitrogen fixation  nitrogen is "fixed" by combining with other  elements to form nitrogen-containing compounds these compounds can be used by living things performed by certain kinds of bacteria nitrogen can also be fixed by lightning strikes

4. legumes  plants which contain nitrogen fixing bacteria in  
  nodules in their roots (e.g. clover, beans, peas,  
 alfalfa, peanuts) Where do  plants take up simple nitrogen compounds from producers  the soil and use it to build proteins and other get nitrogen?  complex nitrogen compounds Where do   consumers get nitrogen by consuming consumersproducers or other consumers. get nitrogen? 

5. Good sources of protein (and therefore nitrogen)

6. Where do  by breaking down complex nitrogen compounds decomposers  in animal wastes and dead organisms get nitrogen? this process (decomposition) returns simple nitrogen compounds to the soil. How does  some bacteria break down nitrogen compounds nitrogen  completely, releasing free nitrogen back into back into the   the atmosphere. atmosphere? 

7. The Nitrogen Cycle Nitrogen moves from the atmosphere to the soil, into living organisms, and back into the atmosphere.

8. The nitrogen in your body might once have been in the body of a.. Wooly mammoth! or a glyptodont! or maybe a giant ground sloth or even Cleopatra!

9. And if you eat meat, some of the nitrogen making up your body was once part of the body of whatever animal you ate!

10. The Nitrogen Cycle in an Aquarium

11. Forms of Nitrogen 1. Ammonia- (NH3) Waste product of animals released during excretion. Ammonia is 
toxic to most organisms. 2. Ammonium- (NH4+) When ammonia is mixed with water, it grabs another hydrogen 
from the water molecules and makes ammonium. This is the only way you will ever 
see ammonia in nature. Also, it tends to stick to soil and clay particles instead of being 
washed away like nitrate. 3. Free Nitrogen- (N2) This is a gas and is one of the most abundant gases in the 
atmosphere. 4. Nitrate- (NO3-) This is usually found as a liquid and is very easily washed out of 
the soil and into groundwater or streams. Farmers don't like when their fertilizer gets 
turned into this, because it washes away too easily and isn't always in the soil long 
enough to help their plants. 5. Nitric Acid- (HNO3) This is the form of nitrogen in acid rain. It is also made by 
lightning. 6. Nitrite- (NO2-) This is a middle step during the process of nitrification. It is very 
toxic to organisms. In a new fish tank, nitrite can build up because the next step of 
nitrification can't continue until all the ammonium is gone, so you have to carefully 
measure NO2- when you first add fish to a tank. 7. Nitrogen oxides- (N2O and NO) These are greenhouse gases and are a middle step 
(intermediate) between nitrate and N2 gas. 8. Organic Nitrogen- (CaHbNcOd) Organic molecules containing nitrogen come in 
many forms from amino acids to proteins to lipids.