1. In the diagram above, add arrows and labels to show the following activities:a) Release of carbon from respiration in the marine food chainb) Mining and burning of coalc) Burning plant material

2. Describe the biological origin of the following geological deposits of coal/oil: ________________________________

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3. Describe the two processes that release carbon in the atmosphere: _______________________________________

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4. Name the four geological reservoirs (sinks), from the diagram above, that can act as a source of carbon:

a) ___________________________________________ c) ___________________________________________

b) ___________________________________________ d) ___________________________________________

5. Explain what would happen to the carbon cycle if there were no decomposers present in an ecosystem:

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6. In natural circumstances, accumulated reserves of carbon as soil, coal, and oil represent a sink or natural diversion from the cycle. Eventually, the carbon in these sinks returns to the cycle.

a) Describe three human activities that affect these sinks in the carbon cycle: ______________________________

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b) Explain two global effects arising from this activity: _________________________________________________

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1. Describe five instances in the nitrogen cycle where bacterial action is important. Include the name of the processes and the changes to the form of nitrogen involved:

a) ____________________________________________________________________________________________

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b) ____________________________________________________________________________________________

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c) ____________________________________________________________________________________________

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d) ____________________________________________________________________________________________

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e) ____________________________________________________________________________________________

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2. Identify two natural processes that fix nitrogen:

a) ___________________________________________ b) ___________________________________________

3. Name the main geological reservoir that provides a source of nitrogen: _____________________________________

4. State the form in which nitrogen is available to most plants: ______________________________________________

5. Name a vital organic compound that plants need nitrogen containing ions for: _______________________________

6. Describe how animals acquire the nitrogen they need: ___________________________________________________

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7. Describe ways in which humans may intervene in the nitrogen cycle: _______________________________________

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1. In the diagram, add a labeled arrow to show where one human activity might intervene in the phosphorous cycle.

2. Name two types of molecules found in living organisms which include phosphorous as a part of their structure:

a) ___________________________________________ b) ___________________________________________

3. List the origin of three forms of inorganic phosphate making up the geological reservoirs (sinks):

a) ____________________________________________________________________________________________

b) ____________________________________________________________________________________________

c) ____________________________________________________________________________________________

4. Describe the processes that must occur on order to make phosphates stored in rocks available to plants again:

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5. Identify one major difference between the phosphorous cycle and the carbon/nitrogen cycles:

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1. Describe two ways in which sulfur can enter the atmosphere from natural sources:

a) ___________________________________________ b) ___________________________________________

2. Describe two ways in which sulfur can enter the atmosphere as a result of human activity:

a) ___________________________________________ b) ___________________________________________

3. Describe three processes that make sulfur in the soil available to uptake by plants:

a) ____________________________________________________________________________________________

b) ____________________________________________________________________________________________

c) ____________________________________________________________________________________________

4. Describe two major roles of sulfur in the biosphere:

a) ___________________________________________ b) ___________________________________________