Pupil Pages
Name: _________________
Group: ____________
The Effect of Pollution (Oil and Dispersant) On Aiptasia pallida
Part A: KABAS
You Should Know:
1. Coral bleaching is a serious consequence of global environment change.
2. Environmental changes, such as increasing water temperatures, decreasing pH,
changes in light due to pollution and pollution directly are related to
coral bleaching
3. How and why Aiptasia pallida can be used as a model organism for coral bleaching.
4. A change in the behavior of Aiptasia pallida (it pulls its tentacles inside) indicates
stress
5. Stress, over time, can lead to a loss of the symbiotic algae in the tentacles which
has harmful effects on the anemone
You Should Be Able To:
1. Describe the process of coral bleaching.
2. Conduct a controlled experiment to test the effect of crude oil and dispersant on
the behavior of Aiptasia pallida.
3. Use a digital camera as a tool to gather data on behavioral changes.
4. Use ADI software to analyze images you get from the experiment.
Research Questions:


What is the effect of crude oil and dispersant on Aiptasia pallida?
How can we quantify a change in the area of an anemone-- which indicates stressusing a digital camera?
Background
Aiptasia anemones, just like corals, have formed a unique partnership, a symbiosis,
with algae. The algae provide the anemone with food (glucose), and, in turn, the algae
are protected and receive nutrients from the anemone host. The brown color of the
Aiptasia anemone, just like corals, is largely due to the presence of the algae. If the
Aiptasia anemones are stressed, they get rid of their algae partners either all at once in
the form of a mucoid ball or as free-swimming individuals. If the algae leave, the color
of the anemones changes to become lighter. It looks as if the anemones have been
bleached.
The same thing happens to corals which live in the ocean. Corals are also
anemones which have symbiotic algae living with them. Unlike Aiptasia, however, coral
anemones secrete a hard outer coating made of calcium carbonate which protects the
anemone. When the coatings of many anemones build up, we call this a coral reef. When
coral anemones in the ocean get stressed due to changes in pH, light or temperature, or
pollution, they too, will release their algae partners. Without the food provided by the
algae, the coral anemones get lighter in color and may eventually die of starvation. A
combination of dead corals and lighter colored corals which are dying makes the reef
look bleached. We call this phenomenon coral bleaching. The death of coral anemones,
and the loss of coral reefs is a very serious problem. Coral reefs are like the tropical
rainforests of the sea because they provide habitat for a diversity of marine life. The
loss of coral reefs is also the loss of habitat for many other species of marine
organisms.
Scientists who are studying coral bleaching have been doing laboratory
experiments on Aiptasia pallida anemones instead of corals. When one species is similar
to another and is used in an experiment instead, it is called a model organism. Aiptasia
anemones are used instead of coral because: they can be kept easily in a lab using
artificial sea water; they reproduce quickly, they are not as delicate as coral anemones
and they do not die if they release their algae under stress. This is because Aiptasia
are able to get food in ways other than solely getting it from the algae. If the algae are
released, Aiptasia can get food by stinging and eating small sea organisms using their
tentacles. So, as long as Aiptasia are given a source of food in the lab, they can be
tested to see how they react to stress without killing them.
http://www.coralscience.org/main/articles/symbiosis-4/aiptasia-a-bleaching
Hypotheses:
If crude oil is added, the volume (area in a 2-dimensional photo) of the Aiptasia pallida
anemones will ______________________ because
____________________________________________________.
If dispersant is added, the volume (area in a 2-dimensional photo) of the Aiptasia pallida
anemones will ______________________ because
____________________________________________________.
Materials
1.
2.
3.
4.
5.
6.
7.
8.
9.
1” x 1” x 1” plastic magnifying box.
A tank with a culture of Aiptasia anemones living in it
Motor oil or vegetable oil
Liquid soap or liquid detergent designed to “cut grease”
2 small cups/beakers – one with oil and one with dispersant/detergent
3 eyedroppers or pipettes
pen or pencil
Index card
8 1/2” x 11” white paper* If you use colored paper ( a color which is drastically
different from the Aiptasia as the background ) you may not need to have to use
color enhancement in ADI to get accurate masked pixels.
10. tripod or ring stand for photographing under constant distance, light conditions,
angle, etc.
11. Digital camera, of course.
12. Place for photographing with stable source of ambient light.
13. ADI software. Can be downloaded from: http://k12s.phast.umass.edu/digital/
Procedure --- Groups 1-5
1. Tape a piece of 8 ½” x 11” piece of white paper down onto the lab bench.
2. Set up a camera tripod/ringstand to take photos under consistent conditions.
3. Make three labels from the index card:
4.
Control
2 drops of oil
2 drops of Oil + 2 drops
of Dispersant
5. Obtain a small plastic magnifying box with a living Aiptasia anemone in it.
6. Place the box in the center of a piece of white paper. Let the anemone
relax for a while so that its tentacles are fully extended. This indicates a
contented (healthy and not stressed) anemone .
7. Take a control photograph of the anemone making sure that the Control label is
visible in the photo.
8. Using an eyedropper, add two drops of oil to the surface of the water in the
magnifying box.
9. Wait 2 minutes.
10. Take a picture of the Aiptasia which has been exposed to oil after 2 minutes.
Make sure the 2 drops of oil label is visible in the photo.
11. To get a clear photo of the Aiptasia which has been exposed to oil, you need to
clear the oil away. Do this by adding 2 drops of dispersant (detergent) to the
surface of the water then QUICKLY take a photo of the Aiptasia as soon as it is
visible.
12. If you did not already put 2 drops Put two drops of dispersant on top of the oil (if
you did not already do this in order to get a good image of the Aiptasia.)
13. After you take a quick photo of the Aiptasia which was exposed to oil, wait two
minutes again.
14. Again, take a photo being sure to include the 2 drops of oil + 2 drops of
dispersant label in the photo.
15. Use the third, clean eyedropper to carefully gather the anemone and return it to
the tank.
Procedure --- Groups 6-11
1. Follow the same steps outlined above but create 2 labels only. You will be testing
the effect of just the dispersant.
Control
2 drops of dispersant
Data Analysis
USING THE ADI SOFTWARE—
1. Download the images of the Aiptasia into your computer.
2. Click on Analyzing Digital Images
3. Click on Enhance Colors and open up the first photo you took of the Aiptasia (the
control).
4. Large image detected—choose yes
5. At Select trim option—choose Full Image at Selected resolution
6. Click on trim and use image
7. Select None
8. Note RGB histograms—the three tall RGB sections represent the white
background. The small (low intensity) bumps in the wings represent the Aiptasia
9. Select predefined enhancement
10. Click on drop down menu—red vs blue normalized—(this is chosen because in the
color histogram, red and green were similar to each other different from blue. In
this example red vs blue was chosen but you get similar results when green vs blue
is chosen.
11. Zoom in and pan around to have the critter be large and centered.
12. Click on Mask Colors.
13. Draw a box within the Aiptasia that covers a good sample of the variety of pixels.
14. Note—minimum and maximum values given for you
15. Click on Apply Mask Test 1. Compare the masked image with the original so see how
closely you have come to replicating the critter in black.
16. Adjust the min/max (play around with those values) and repeat Apply Mask Test 1
until you have closely replicated the critter in black.
17. Click on Spatial Analysis.
18. Click on Polygon Tool. Toggle back from the masked image to the original image.
19. Draw a polygon around the original image.
20. Toggle back to the masked image. Note the number of masked pixels inside the
polygon that you drew.
21. Repeat with the other photos and compare.
22. Compare the data you got with other groups who did the same experiment.
Conclusion
Do the data support your first hypothesis? Explain.
Do the data support your second hypothesis? Explain.
Questions to Consider
1. What patterns, if any, did you notice in the data?
2. How do the data from your group compare with the data from other groups?
3. What implications might the data have for the effect of oil spills and dispersants on
other kinds of bottom-dwelling organisms?
CHECK FOR UNDERSTANDING
Reread the KABAS to make sure you know and are able to do the major concepts and
skills in this investigation.