Name __________Bezawit Belew_________________________ Date _____________
Cycling WebQuest
Directions: Visit the following websites and answer the related questions. Your goal is to gain a
better understanding of the carbon and nitrogen cycles.
Background: In biogeochemical cycles (including carbon, water and nitrogen cycles), elements are
transported between the atmosphere, biosphere (living things), hydrosphere (water), and geosphere
(rocks, minerals, and soils). These cycles help us remember that Earth is a complex system.
Carbon Cycle:
Go to http://www.windows.ucar.edu/tour/link=/earth/Water/co2_cycle.html and answer these
questions:
1. Draw the carbon cycle (on a separate piece of paper)
2. How does carbon exist in the atmosphere?
Attached with oxygen, in the form of carbon dioxide
3. How are fossil fuels created? Explain.
When plants and animals die, and are buried miles underground, they’ll become fossil fuels in
millions and millions of year
4. Describe two ways that carbon enters the atmosphere.
When we exhale, we release carbon dioxide in the atmosphere
When fossil fuels are burned for different reasons, carbon dioxide gets to atmosphere with
great amount
5. How are the oceans involved in the carbon cycle?
They soak up some carbon from the atmosphere
6. How is the temperature of the Earth partly controlled by carbon?
Carbon has the ability to trap heat, so without it, earth would be frozen
7. What role do rocks have within the carbon cycle?
In the process of weathering of rocks, carbon can be added to surface water
Go to http://www.windows.ucar.edu/earth/climate/carbon_cycle.html to play the carbon cycle
game. You are a carbon atom!
8. Where are you starting within the carbon cycle?
I’m starting as an underground fossil fuel, which has been released to the atmoshphere
“Click to begin your journey”
9. How much of the atmosphere is made of carbon dioxide (CO2)?
0.04%
10. By how much has CO2 increased in the atmosphere during the past 150 years?
30%
As you work through this game, take some notes about where you go as a carbon atom. Make sure
you visit all reservoirs!
11. Next stop = ____surface ocean_____________________________________
What did you learn?
ocean absorbs more carbon dioxide from than the land does
Cold water absorbs carbon faster than warm water.
12. Next stop = ___Deep Ocean______________________________________
What did you learn?
Carbon comes from circulation with the surface ocean and dead and decaying marine life.
It stays there for hundreds of years before moving out
The deep ocean accounts for more than _65____ % of the Earth’s carbon.
How much carbon does the surface ocean absorb from the atmosphere each year?
True or False: When plants die and decay, they bring carbon into soil. true
13. Next stop = ______Marine Life___________________________________
What did you learn?
phytoplankton take in carbon to make the nutrition they need through photosynthesis.
Marine life can’t survive without carbon, but too much is also harmful
14. Next stop = ______Land Plants___________________________________
What did you learn?
Absorb it from sun in form of energy during photosynthesis
Plants absorb and release carbondioxide
15. Next stop = _____Soil____________________
What did you learn?
Comes form dead plants or animals
Stores about 3% of earth’s carbon
When carbon enters the deep ocean, how long does it stay there?
__More than hundred years_____________
True or False: Phytoplankton are tiny plants and algae that float in the ocean and take up carbon
dioxide as they grow. True
True or False: Plants both absorb CO2
from the atmosphere and release it into the atmosphere. True
Nitrogen Cycle:
Go to http://www.elmhurst.edu/~chm/onlcourse/chm110/outlines/nitrogencycle.html and answer
these questions.
16. What are the two conditions under which nitrogen will react with oxygen? (In other words, what is
necessary for nitrogen in the air to combine with oxygen?)
High temperatures and pressures
17. What are the two compounds that are formed when nitrogen combines with oxygen?
Nitric Oxide and Nitrogen dioxide
18. How does nitric acid (HNO3) form?
When nitrogen dioxide reacts with water (rain)
19. Why is nitric acid (HNO3) important?
Used as nutrient by plants
Go to: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/N/NitrogenCycle.html and answer these
questions.
20. What percentage of the air we breathe is nitrogen?
79%
21. Even though considerable nitrogen is available in the air, most plants do not use the nitrogen (N2)
found in the air. Why not?
They can only use it in fixed form
22. In what compounds can plants use nitrogen?
Nitrate, Ammonium, Urea
23. How do animals get the nitrogen they need?
By feeding on animals
24. Atmospheric nitrogen (N2) is pretty inert. This means that it does not easily break apart. When
molecules do not break apart easily, it is difficult (or impossible) for organisms to use them as a nutrient
source. As a result, nitrogen fixation is the term used to describe the process of breaking up N2
a. What is atmospheric fixation?
Completed by the energy of lightning, breaks the molecules
b. What is industrial fixation? [This is how artificial fertilizers are made.]
Done under great pressure at 600 Celsius and with the use of catalyst
c. What is biological fixation? (In your answer, describe the types of plants associated with the symbiotic
relationship.)
Ability to fix nitrogen naturally, only certain bacteria and archaea eg. Termites, shipworms, leugumes,
alders
Go to: http://www.physicalgeography.net/fundamentals/9s.html and answer these questions.
25. Draw the nitrogen cycle: On a separate piece of paper: (Remember there are other diagrams on the
previous websites.) If you’re not sure what a term means, look through the reading and links for help.
26. Why is nitrogen needed by plants and animals?
They need it for metabolism, reproduction and growth and DNA
Go to http://www.mbgnet.net/fresh/cycle/index.html. Answer the following questions.
1. Define "water cycle".
A complex process that gives us water to everything including weather patterns
2. What fraction of the Earth’s surface is covered in water?
97%
3. What percentage of all the Earth’s water is in a form that is useable to humans and land
animals?
3%
Click on http://www.mbgnet.net/fresh/cycle/concepts.htm.Answer the following questions.
1. Evaporation is the process where a liquid changes from its _liquid_________ state to a
__Gaseous_________ state.
2. Why is evaporated water so clean?
Impurities are left behind
3. Condensation occurs when a __gas__________ is changed into a __liquid________.
4. Condensation is the opposite of __Evaporaiton__________.
5. When the __temprature______________ and ____Atmospheric Pressure_______________ are right,
the small droplets of water in clouds form larger droplets and precipitation occurs.
6. Define transpiration: The process of evaporation through plants
7. Define precolation: When the small droplets of water in clouds form larger droplets and
precipitation occurs, rain.
Go to http://www.mbgnet.net/fresh/cycle/cycle.htm. Answer the following questions.
1. Using the terms "evaporation", "condensation", and "precipitation", explain the water cycle in
your own words.
Water evaporates from surface of the earth to the atmosphere and it molecules condense into
clouds, when they are large enough they precipitation occurs in form of rain.
2. What factor is most important in determining whether water is a solid, liquid, or gas?
Temperature
3. Is the amount of water on Earth always changing or is it a constant amount?
It remains constant