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)
Done.
2. How does carbon exist in the atmosphere?
In the atmosphere, carbon is attached to oxygen in a gas called carbon dioxide (CO2).
3. How are fossil fuels created? Explain.
When plants and animals die, their bodies, wood and leaves decay bringing the carbon into the ground. they decay and turn into fossil fuels
4. Describe two ways that carbon enters the atmosphere.
when you brethe, you brethe it out, and when animals and plants get rid of it using respiration
5. How are the oceans involved in the carbon cycle?
the ocean and other bodies of water, suck up carbon from the atmosphere
6. How is the temperature of the Earth partly controlled by carbon?
Carbon dioxide is a greenhouse gas and traps heat in the atmosphere. Without it and other greenhouse gases, Earth would be a frozen world.
7. What role do rocks have within the carbon cycle?
Carbon moves through our planet over longer time scales as well. For example, over millions of years weathering of rocks on land can add carbon to surface water which eventually runs off to the ocean.
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?
in the atmosphere
“Click to begin your journey”
9. How much of the atmosphere is made of carbon dioxide (CO2)?
Only a small amount (0.04%) of the atmosphere is made of carbon dioxide
10. By how much has CO2 increased in the atmosphere during the past 150 years?
cO2 has increased by 30% in the atmosphere in the past 150 years
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?
Cold water absorbs carbon faster than warm water.12. Next stop = ______________________________The deep ocean___________
What did you learn? The deep ocean holds more than 65% of the Earth's carbon.
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? 90 gigatons
True or False: When plants die and decay, they bring carbon into soil. True
13. Next stop = _____________Marine Life____________________________
What did you learn?
Marine life cannot survive without carbon, but too much is also bad14. Next stop = __________________________Land plants_______________
What did you learn?
As more carbon dioxide is added to our atmosphere, plants will be able to grow faster. Plants also release carbon back to the atmosphere by respiration. 15. Next stop = _____Soil____________________________________
What did you learn?
Soils store about 3% of Earth's carbon.When carbon enters the deep ocean, how long does it stay there?
___________hundreds of 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.
Nitrogen Cycle: True
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?)
Nitrogen will only react with oxygen in the presence of high temperatures and pressures found near lightning bolts and in combustion reactions in power plants or internal combustion engines.17. What are the two compounds that are formed when nitrogen combines with oxygen?
Nitric oxide, NO, and nitrogen dioxide, NO2, are formed under these conditions.18. How does nitric acid (HNO3) form? nitrogen dioxide may react with water in rain to form nitric acid, HNO319. Why is nitric acid (HNO3) important?
The nitrates thus formed may be utilized by plants as a nutrient.
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% of the air we breathe is nitrogen
21. Even though considerable nitrogen is available in the air, most plants do not use the nitrogen
(N2) found in the air. Why not?
plants must secure their nitrogen in "fixed" form.
22. In what compounds can plants use nitrogen?
nitrate ions (NO3−), ammonium ions (NH4+), urea (NH2)2CO 23. How do animals get the nitrogen they need? Animals secure their nitrogen (and all other) compounds from plants (or animals that have fed on plants).
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?
The enormous energy of lightning breaks nitrogen molecules and enables their atoms to combine with oxygen in the air forming nitrogen oxides b. What is industrial fixation? at a temperature of 600°C, and with the use of a catalyst, atmospheric nitrogen and hydrogen (usually derived from natural gas or petroleum) can be combined to form ammonia (NH3). [This is how artificial fertilizers are made.]
c. What is biological fixation? (In your answer, describe the types of plants associated
with the symbiotic relationship.)
The ability to fix nitrogen is found only in certain bacteria and archaea. maybe sun flower plants 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?
to produce a number of complex organic molecules like amino acids, proteins, and nucleic acids Go to http://www.mbgnet.net/fresh/cycle/index.htm. Answer the following questions.
1. Define "water cycle".
the cycle of processes by which water circulates between the earth's oceans, atmosphere, and land 2. What fraction of the Earth’s surface is covered in water?
70% of the earths surface is covered in water
3. What percentage of all the Earth’s water is in a form that is useable to humans and land
animals?
30% of the earth's water is in a form that is usable by humans and land animals
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 __________ state to a
___________ state.
2. Why is evaporated water so clean?
3. Condensation occurs when a ____________ is changed into a __________.
4. Condensation is the opposite of ____________.
5. When the ________________ and ___________________ are right, the small droplets of
water in clouds form larger droplets and precipitation occurs.
6. Define transpiration:
7. Define percolation:
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.
2. What factor is most important in determining whether water is a solid, liquid, or gas?
3. Is the amount of water on Earth always changing or is it a constant amount
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)
Done.
2. How does carbon exist in the atmosphere?
In the atmosphere, carbon is attached to oxygen in a gas called carbon dioxide (CO2).
3. How are fossil fuels created? Explain.
When plants and animals die, their bodies, wood and leaves decay bringing the carbon into the ground. they decay and turn into fossil fuels
4. Describe two ways that carbon enters the atmosphere.
when you brethe, you brethe it out, and when animals and plants get rid of it using respiration
5. How are the oceans involved in the carbon cycle?
the ocean and other bodies of water, suck up carbon from the atmosphere
6. How is the temperature of the Earth partly controlled by carbon?
Carbon dioxide is a greenhouse gas and traps heat in the atmosphere. Without it and other greenhouse gases, Earth would be a frozen world.
7. What role do rocks have within the carbon cycle?
Carbon moves through our planet over longer time scales as well. For example, over millions of years weathering of rocks on land can add carbon to surface water which eventually runs off to the ocean.
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?
in the atmosphere
“Click to begin your journey”
9. How much of the atmosphere is made of carbon dioxide (CO2)?
Only a small amount (0.04%) of the atmosphere is made of carbon dioxide
10. By how much has CO2 increased in the atmosphere during the past 150 years?
cO2 has increased by 30% in the atmosphere in the past 150 years
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?
Cold water absorbs carbon faster than warm water.12. Next stop = ______________________________The deep ocean___________
What did you learn? The deep ocean holds more than 65% of the Earth's carbon.
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? 90 gigatons
True or False: When plants die and decay, they bring carbon into soil. True
13. Next stop = _____________Marine Life____________________________
What did you learn?
Marine life cannot survive without carbon, but too much is also bad14. Next stop = __________________________Land plants_______________
What did you learn?
As more carbon dioxide is added to our atmosphere, plants will be able to grow faster. Plants also release carbon back to the atmosphere by respiration. 15. Next stop = _____Soil____________________________________
What did you learn?
Soils store about 3% of Earth's carbon.When carbon enters the deep ocean, how long does it stay there?
___________hundreds of 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.
Nitrogen Cycle: True
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?)
Nitrogen will only react with oxygen in the presence of high temperatures and pressures found near lightning bolts and in combustion reactions in power plants or internal combustion engines.17. What are the two compounds that are formed when nitrogen combines with oxygen?
Nitric oxide, NO, and nitrogen dioxide, NO2, are formed under these conditions.18. How does nitric acid (HNO3) form? nitrogen dioxide may react with water in rain to form nitric acid, HNO319. Why is nitric acid (HNO3) important?
The nitrates thus formed may be utilized by plants as a nutrient.
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% of the air we breathe is nitrogen
21. Even though considerable nitrogen is available in the air, most plants do not use the nitrogen
(N2) found in the air. Why not?
plants must secure their nitrogen in "fixed" form.
22. In what compounds can plants use nitrogen?
nitrate ions (NO3−), ammonium ions (NH4+), urea (NH2)2CO 23. How do animals get the nitrogen they need? Animals secure their nitrogen (and all other) compounds from plants (or animals that have fed on plants).
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?
The enormous energy of lightning breaks nitrogen molecules and enables their atoms to combine with oxygen in the air forming nitrogen oxides b. What is industrial fixation? at a temperature of 600°C, and with the use of a catalyst, atmospheric nitrogen and hydrogen (usually derived from natural gas or petroleum) can be combined to form ammonia (NH3). [This is how artificial fertilizers are made.]
c. What is biological fixation? (In your answer, describe the types of plants associated
with the symbiotic relationship.)
The ability to fix nitrogen is found only in certain bacteria and archaea. maybe sun flower plants 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?
to produce a number of complex organic molecules like amino acids, proteins, and nucleic acids Go to http://www.mbgnet.net/fresh/cycle/index.htm. Answer the following questions.
1. Define "water cycle".
the cycle of processes by which water circulates between the earth's oceans, atmosphere, and land 2. What fraction of the Earth’s surface is covered in water?
70% of the earths surface is covered in water
3. What percentage of all the Earth’s water is in a form that is useable to humans and land
animals?
30% of the earth's water is in a form that is usable by humans and land animals
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 __________ state to a
___________ state.
2. Why is evaporated water so clean?
3. Condensation occurs when a ____________ is changed into a __________.
4. Condensation is the opposite of ____________.
5. When the ________________ and ___________________ are right, the small droplets of
water in clouds form larger droplets and precipitation occurs.
6. Define transpiration:
7. Define percolation:
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.
2. What factor is most important in determining whether water is a solid, liquid, or gas?
3. Is the amount of water on Earth always changing or is it a constant amount