Name Terre Block_ Date 09-25-12
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? Carbon exits as a gas, CO2
3. How are fossil fuels created? Explain. Fossil fuels created by carbons being taken
underground by decaying matter.
4. Describe two ways that carbon enters the atmosphere. 1. Burning fossil fuels from
factories. 2. Animal respiration is when you breathe and animals breathe out CO2
emitting it in atmosphere.
5. How are the oceans involved in the carbon cycle? The oceans, and other bodies
of water, soak 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.
7. What role do rocks have within the carbon cycle? 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? The Atmosphere
9. How much of the atmosphere is made of carbon dioxide (CO2)? Small amount
0.04.
10. By how much has CO2 increased in the atmosphere during the past 150 years? It
has increased by 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? The ocean absorbs more carbon dioxide from the atmosphere
than the land does. The surface ocean takes in approximately 90 Gigatons of carbon
per year. Cold water absorbs carbon faster than warm water.
12. Next stop = Deep Ocean
What did you learn? Deep Ocean gets carbon from circulation with the surface ocean
and dead and decaying marine life. When carbon gets to the deep ocean, it usually
stays there for hundreds of years before moving on. 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 of
carbon per year.
True or False: When plants die and decay, they bring carbon into soil. true
13. Next stop = Land Plants
What did you learn? As more carbon dioxide is added to our atmosphere, plants
will be able to grow faster, photosynthesis. Plants also release carbon back to the
atmosphere by respiration.
14. Next stop = Soil
What did you learn? Soil called detritus, which is decomposing plants and animals.
Soil is also made of inorganic parts such as sand, silt, and clay. Soils store about 3%
of Earth's carbon. As bacteria and fungi breakdown the detritus, carbon is sent into the
atmosphere.
15. Next stop = Marine Life
What did you learn? Tiny marine organisms called phytoplankton take in carbon
to make the nutrition they need through a process called photosynthesis. The
phytoplanktons are eaten by larger marine life. Marine life cannot survive without
carbon, but high levels of carbon dissolved in ocean waters are harmful to marine
organisms such as algae, mollusks and corals.
When carbon enters the deep ocean, how long does it stay there? 100’s of years
True or False: Phytoplankton are tiny plants and algae that float in the ocean and take
up carbon dioxide as they grow. False
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 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? Eventually nitrogen dioxide may react with
water in rain to form nitric acid, HNO3.
19. 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%
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−) ammonia
(NH3) urea (NH2)2CO
23. How do animals get the nitrogen they need? 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. These dissolve in rain, forming nitrates, which are carried to the earth.
b. What is industrial fixation? [This is how artificial fertilizers are made.] Under
great pressure, at a temperature of 600°C, atmospheric nitrogen and hydrogen can be
combined to form ammonia (NH3). Ammonia can be used directly as fertilizer, but
most of its is further processed to urea and ammonium nitrate (NH4NO3).
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. Some live in a symbiotic relationship with plants of the
legume family (e.g., soybeans, alfalfa). Some establish symbiotic relationships with
plants other than legumes (e.g., 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? Nitrogen is used by living
organisms 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 water cycle, a complex process that not only gives us
water to drink, fish to eat, but also weather patterns that help grow our crops.
2.
What fraction of the Earth’s surface is covered in water? 3/4ths
3. What percentage of all the Earth’s water is in a form that is useable to humans
and land animals? 1%
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 gaseous state.
2. Why is evaporated water so clean? Impurities in the water are left behind.
3.
Condensation occurs when a gas is changed into a Liquid. True
4.
Condensation is the opposite of Evaporation. True
5.
When the Temperature and Atmospheric pressure are right, the small droplets of
water in clouds form larger droplets and precipitation occurs.
6.
Define transpiration: process of evaporation through plant leaves
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.
Evaporation, condensation and precipitation, is when water travels from the
surface of the Earth goes into the atmosphere, and returns to Earth again.
Evaporation is water moving to atmosphere from liquid to gas, condensation is
when water vapor forms cloud in atmosphere, and precipitation is the vapor
turning into a liquid as rainfall.
2.
What factor is most important in determining whether water is a solid, liquid,
or gas? Tempature
3.
Is the amount of water on Earth always changing or is it a constant amount?
Amount of water on earth is constant never changes.