Carbon-Oxygen Cycle
(pages 43-46)
Assignment:
1.
Define carbon sinks and provide three examples.
2.
Define carbon sources and provide three examples.
3.
Explain, using the relationship between carbon sinks and sources, how the
atmosphere is currently seeing elevated levels of carbon dioxide.
4.
Given the following data:
Processes
Amount of CO2 in Biosphere (tonnes/year)
Respiration by plants
Respiration by soil organisms
Release from decomposition
Combustion of fossil fuels
Deforestation
Photosynthesis
CO2 dissolved in ocean
Carbon stored in sea shells
Carbon stored on ocean floor
a.
50 x 109
50 x 109
100 x 109
5 x 109
2 x 109
100 x 109
55 x 109
38 x 109
11 x 109
Total the amount of carbon dioxide from all sources of carbon sinks.
Answer: __________________ x 109 tonnes/year
b.
Total the amount of carbon dioxide from all sources of carbon sources.
Answer: __________________ x 109 tonnes/year
c.
Identify the process(s) that most likely explain the cause of the imbalance
between the numbers.
d.
Plot a bar graph of the total tonnes/ year of carbon dioxide between the sinks
and the sources.
Title: _____________________________________________________
Axis Title: ____________________________________________
Lab Activity
Do animals produce carbon dioxide?
a.
b.
Obtain a test tube from the test tube rack
Fill test tube with tap water. Add five drops of bromothymol blue to the test
tube.
Using a straw provided, bubble your exhaled air into the test tube for 10 min.
Observe colour change.
c.
Analysis
1.
What two gases do you exhale? One of them reacts with water to produce an
acid. Identify which of the two exhaled gases it is and use your test results to
support your answer.
2.
Do animals (consumers) produce carbon dioxide?
Do plants use carbon dioxide?
a. Add a water plant to the test tube that you just finished blowing carbon dioxide
into. Record the initial colour of the test tube.
b. Stopper the test tube.
c. Place the test tube in the test tube rack and turn on the light source. Leave it set
up for 30 minutes.
d. Record your observations at 30 minutes
Analysis
1.
Complete the table below.
Test
Tube
Initial Colour
of Solution in
Test Tube
Significance of
Initial Colour in Test
Tube
Final Colour
of Solution in
Test Tube
1
2.
Do plants use carbon dioxide? Support your answer
Significance of
Final Colour in
Test Tube
3.
Explain, in detail, the process that plants perform to rapidly cycle carbon
dioxide.
Extension Questions:
Click on NASA’s Earth Observatory website:
http://earthobservatory.nasa.gov/Features/CarbonCycle/page2.php
In the upper right corner of the website are sections that we’re going to look into.
a.
What is the difference between rapid and slow cycling of carbon? (View
The Slow Carbon Cycle and The Fast Carbon Cycle of the website)
b.
Its been stated that the atmosphere now contains more carbon than at any
time in at least two million years. Use Changes in the Carbon Cycle
chapter to account how this may be occurring.
Carbon Cycle
Label the following diagram using these terms:
CO2 in the atmosphere, Cellular Respiration, Death and Decomposition, CO 2 dissolved in
water, photosynthesis, Combustion, Consumption, Fossil Fuels