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.