NAME ____________________________________ DATE ________________________ PER __________
NITROGEN CYCLE WEBQUEST
http://www.visionlearning.com/en/library/Earth-Science/6/The-Nitrogen-Cycle/98
Nitrogen Cycle
1. Nitrogen is an essential component of what cellular building blocks?
2. What form of nitrogen in found in the atmosphere? Can organisms use that nitrogen?
3. Processes within the nitrogen cycle progress at a _______ rate than geological processes like plate
motion.
 faster
 slower
4. What organisms play a major role in nitrogen transformations?
Processes in the nitrogen cycle. Summarize each process in the nitrogen cycle with the equation and one
sentence.
Nitrogen fixation
Nitrogen uptake
Nitrogen mineralization
Nitrification
Denitrification
5. Look at Figure 3.
a. What does anthropogenic mean?
b. What is the largest source of anthropogenic nitrogen fixation?
c. When did this source start to increase dramatically?
6. Which process returns nitrogen gas to the atmosphere?
a. Nitrification
b. Denitrification
7. How have humans altered the N cycle?
8. What are three environment consequences of these changes?
a.
b.
c.
Answer the questions to the quiz (with blue font) before you check your answers. Then you can fix them
with a different colored font. I just want to see how you did. As long as you complete the answers you will
get full credit.
1. What is the most common way that nitrogen fixation occurs?
 Lightning
 fossil fuel combustion
 nitrogen fixing bacteria
 forest fires
2. Atmospheric nitrogen (N2 gas) is easily taken up and used by plants and animals.
 false
 true
3. Which of the following is a component of acid rain?
 organic nitrogen
 nitrogen oxides
 ammonium
 sulfur dioxide
4. Organic nitrogen is converted back to inorganic nitrogen like ammonium through the process of
 Nitrogen fixation
 decay.
 nitrofication.
 none of the choices.
5. Eutrophication in coastal waters can cause an increase in
 Respiratory diseases in fish
 harmful algal blooms.
 agricultural productivity.
 denitrification.
6. Ammonium (NH4) stays in soil, while nitrate (NO3) is easily leached out. Why do they behave so differently?
 NO3 is broken down by bacteria, so it is easily carried away
 NH4has a positive charge and sticks to soil particles.
 NH4 is unavailable to organisms, so it remains unchanged in the soil.
 NO3 is only produced when water is flowing through soil.
7. Which process releases dinitrogen gas (N2) back into the atmosphere?
 denitrification
 decay
 nitrogen fixation
 nitrification
8. Once bacteria have fixed nitrogen, it can be taken up by plants and animals, where it is used in the
production of
 Nitrogen oxides
 proteins.
 carbohydrates.
 energy.
9. Synthetic fertilizers add _____________ to the soil.
 Fixed nitrogen (ammonium)
 organic nitrogen

nitrogen oxides
 nitrate
10. Legumes host nitrogen fixing bacteria, and thus are good crops to plant to replenish the soil.
 true
 false