APES - Nitrogen Cycle

AP Environmental Science Unit 1 + 2 Nitrogen cycle

Step 1: Nitrogen Fixation

Atmospheric nitrogen is turned into ammonia by nitrogen fixing bacteria or a lightning strike

Step 2: Ammonification

Bacteria breaks down chemicals that contain nitrogen from dead matter into ammonia

Step 3: Nitrification

Bacteria turns ammonia into nitrate ions which is most easily taken up by plants

Step 4: Assimilation

Plants take nitrate ions from the soil and use them to build tissue

Step 5: Denitrification

Another bacteria takes soil nitrate and turns it into atmospheric nitrogen