Pollution Online Lab: Stream Ecology
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Username: Tarboro
Quick Launch: 870
Data & Observations
Use the BioScope to explore the effect that pollution can have on a
stream ecosystem. This activity requires that you make observations and
consider what the results mean. For all experiments, you will use a virtual
water sensor to sample the water upstream and downstream of the
pollution source.
Part I: Exploring the BioScope
A.
B.
C.
D.
Launch the BioScope.
Observe the virtual stream and note the conditions as you answer
the following questions.:
1. In which direction (left-to-right or right-to-left) does the
stream flow? Is the portion of the stream at the extreme left
considered to be upstream or downstream? (By definition,
water flows from upstream to downstream.)
2. What is the temperature of the water in the stream?
3. What is the depth of the stream?
4. What is the velocity of the stream?
Find the outlet pipe from the farm/power plant/city. This outlet is
the point where the selected pollutant enters the stream. In the
exercises that follow it will be referred to as the pollutant source
or simply as the source. Notice that you can take samples up to
500,000 m (500 Km) downstream from the source.
Slide the Sensor along the stream to the left (upstream) and to the
right (downstream) and observe the Results panel.
5. What is the distance value at the source?
6. What happens to the distance values as you move upstream
from the source?
7. Do the distance values increase or decrease as you move
downstream from the source?
Part II: Establish the Baseline Conditions
E.
Using the Sensor, sample the non-polluted stream at the
farm/power plant/city by positioning the Sensor so that the
distance equals 0 x 1000 m. 8. Record the values for temperature and dissolved O2 in the 0
row on the left side of Table 1 on the Data Sheet.
9. Indicate the species found by placing an "X" in the
appropriate boxes in Table 1.
F. Without modifying the stream conditions, sample the stream water.
Slide the Sensor to the left or to the right to collect samples.
10. Complete the left side of Table 1 by sampling each of the
indicated locations downstream of the pollution source
and one location upstream.
Part III: Effects of a Pollutant on the Stream
G.
Use the drop-down menus in the Select a Pollutant panel to select
Animal Waste and a Volume(pollutant):Volume(stream) ratio of 1:500.
H.
Sample the water at the source, at each of the indicated distances
downstream and one location upstream of the pollution source, as
indicated in Table 1. Record your answers to questions 11 and 12 on
the right side of Table 1.
11. Record the values for temperature and dissolved O2.
12. Indicate the species found by placing an "X" in the
appropriate boxes.
I. Consider the entire stream as you answer the following questions.
13. Did the pollutant affect the temperature, dissolved O2,
or both? Explain.
14. Were the species that inhabit the stream affected by the
pollutant? In other words, did some species disappear or
did new species appear? Explain.
15. Did the pollutant affect the entire stream or were the
effects confined to a small area? Explain.
Analysis & Conclusions
In this section, you will graph and analyze the data you collected from
the BioScope. You will determine the effects of pollutants on a stream.
Use the following guidelines to graph the data from Tables 1 and 2:
Answer all questions based on the information and data collected.
1. Plot the data for oxygen concentration and stream location
for both the non-polluted and polluted stream on the same
graph.
a. Begin by completely labeling your axis and the title of you
graph.
b. Plot all the points for the non-polluted stream and
connect with a line.
c. In a different color, plot all the points for the polluted
stream and connect with a line. Make a color key.
Effects of Pollution on a Stream
Refer to Table 1 and Graph 1 as you answer the following questions:
2. Why was it important to determine the baseline conditions
before assessing the effects of the pollutants on the stream?
3. Describe the shapes of the dissolved O2 curve for the nonpolluted stream.
4. Describe the shapes of the dissolved O2 curve for the
polluted stream.
5. Compare the dissolved O2 curves for the non-polluted and
polluted streams. Describe any similarities or differences.
6. Describe any changes in the types and location of species
living in the non-polluted stream.
7. Describe any changes in the types and location of species
living in the polluted stream. How do they differ from the
non-polluted stream?
8. Based on your data, answer why different species survive in
some locations but not others. Cite specific examples. Name
organisms and the conditions under which they appear or
disappear.
9. Based on your data, identify species that, by their presence
or by their absence, may serve as indicators of polluted
water.
10.
What was the minimum distance needed for the
stream conditions and species composition to return to
normal?