Ecosphere Analysis Questions
1. Diagram: Draw a diagram of how you think the ecosphere works. Include all organisms and show
the flow of H O N C and P. Use your graphic organizer to help make this.
2. When the algae are removed everything dies. Why? Support your argument with data.
3. When the bacteria are removed, everything dies. Why? Support your argument with data.
4. When the shrimp is removed, the sphere survives indefinitely. How is this possible? Support
with data.
5. In a sphere with algae only (no bacteria or shrimp), the algae dies.
a) why do you think the algae dies?
b) Why doesn’t the algae breakdown or decompose?
6. One of the functional roles of the bacteria is to keep the sphere clean by removing the shrimp
waste. In the first trials to create a functioning sphere, the researchers used small snails similar to
those in a fish tank. These snails are known to eat the waste of fish, brine shrimp and other marine
organisms. Although the snails were able to keep the sphere “clean” the brine shrimp and algae did
not survive for a long period of time. (Data on the composition of the sea water with shrimp, algae,
and snails is included below.)
Ecosphere Water Quality Data - No Bacteria With Snails, Shrimp and Algae
Parameter
Turbidity
Acceptable
Range
10 - 25
NTU
> 5.0 mg/L
Day 1
Day 10
Day 20
Day 30
Day 100+
12
16
15
13
14
Dissolved
6.3
6.6
6.4
6.5
6.3
Oxygen
Carbon
> 2.5 mg/L 3.1
3.5
3.2
3.3
3.2
Dioxide
Oxides of
0.05 - 0.09 0.06
0.057
0.053
0.05
0.041
Nitrogen
mg/L
(NOx)
Ammonia
0.02 - 0.05 0.03
0.035
0.041
0.045
0.044
(NHx)
mg/L
Organic
0.010 0.015
0.025
0.029
0.038
0.037
Phosphoru 0.05 mg/L
s (P)
Dissolved
0.02 - 0.09 0.05
0.045
0.039
0.031
0.009
Phosphate mg/L
s (POx)
Use the data above to explain why the snails were not able to keep the ecosphere alive.
a. Which parameters were not within acceptable levels?
b. Explain why you think this is and its effect on the ecosphere.
7. If the sphere is placed in a closed box (a dark environment) after a period of weeks
everything in the sphere dies. Why does this happen?
Ecosphere Analysis Questions
8. Draw a diagram to show the flow of energy through the ecosphere. Include units of energy.
Start at 100 units from the sun.
9. Consider the following statement: If energy cycles like matter does, then I should be able to
put a plant in the sunlight for a week, then remove it from the light and it should survive in a
box (or unlit place) for years because the energy it was supplied with would keep cycling.
But we know that this is not true – the plant dies. Explain why this happens.
10. Below is a data table showing the water quality over the first 100 days of an experiment in
which both bacteria and shrimp are removed so that algae is the only living organism. Does
the data in the table support your explanation as to why the algae die (in number 5)?
Refer to specific parameters (turbidity, dissolved oxygen, carbon dioxide, etc) in the table
to defend your explanation.
Ecosphere Water Quality Data – Algae Only
No Shrimp or Bacteria
Parameter
Acceptable Day 1
Day 10
Day 20
Day 30
Day 100
Range
Turbidity
10 – 25 NTU 12
13
11
13
12
Dissolved
> 5.0 mg/L
6.5
6.6
6.6
6.5
6.3
Oxygen
Carbon
> 2.5 mg/L
3.1
3.5
3.3
3.3
3.4
Dioxide
Oxides of
0.05 – 0.09
0.06
0.057
0.053
0.05
0.041*
Nitrogen
mg/L
(NOx)
Organic
0.010 – 0.05 0.021
0.026
0.034
0.041
0.052*
Nitrogen (N) mg/L
Organic
0.010 - 0.05 0.015
0.025
0.032
0.043
0.053*
Phosphorus mg/L
(P)
Dissolved
0.02 - 0.09
0.05
0.041
0.032
0.021
0.011*
Phosphates mg/L
(POx)
11. Look again at the data on dissolved oxygen and carbon dioxide. In the sphere that contains
algae only (no bacteria or brine shrimp), where does the oxygen and carbon dioxide in the
ecosphere come from? Explain in detail and include a drawing/diagram if it aids in your
explanation.
12. If the sphere is placed in a closed box (a dark environment) for three days, the algae will not
immediately die, but it will lose mass. Why do the algae lose mass and where does this mass
go?
13. Based on your explanation in questions 10-12, go back and revise your explanation of
number 5, if necessary. In your explanation or revision make sure to refer to data in the
table.
Ecosphere Analysis Questions
Conclusion: Look at your day 1 diagram (class notes 2) and the diagram you made for
number 1 on this handout. What were you wrong about? Is there anything you still need to
change in your diagram for #1? Make any necessary changes. Draw, color and label your
final diagram on a separate piece of paper.