Name: _________________ Block _______ Start Date _______ Due Date _______
Lab: The Effect of Ultraviolet Radiation on Plankton (Brine Shrimp)
Adapted by Marilyn Jesrani from the following source: http://omp.gso.uri.edu/doee/teacher/pdf/act19.pdf
Ultraviolet light (UV) not only bleaches out colors on paper and other materials but it also
causes plastic to break down after it has been exposed to sunlight for a long time. When human
skin cells are exposed to strong sunlight, the ultraviolet part of the light can cause damage, as
little as sunburn or as severe as skin cancer. UV rays can be blocked or filtered by sun block
lotions, water, and the ozone layer in the atmosphere.
Ozone (O3) is a gas located in the stratosphere that protects the Earth from harmful ultraviolet
radiation. Humans have added certain chemicals to the atmosphere that are destroying this
layer of ozone. Since the ozone in the earth's atmosphere protects the surface of the earth from
receiving too much ultraviolet light, we may begin to have severe problems if ozone continues to
become depleted.
Although seawater also acts as a filter to UV, there is not enough water above the organisms
that live close to the surface of the ocean to really protect them. Scientists worry about what
effects increasing amounts of ultraviolet light may have on such surface dwellers as plankton
and krill. Since these sea creatures can't just rub on some sun block, what will happen to them?
Further, these creatures are important to the aquatic food chain. Plankton is an important food
source for many fish and water mammals such as whales.
In this activity, observations will be made on how different amounts of ultraviolet light affect a
kind of plankton called "brine shrimp". These planktons are also known by the name "Sea
Monkeys" or "fairy shrimp". "Brine shrimp" are tiny animals that live in very salty water, such as
salt ponds and lagoons. They are being used in this lab because they are very easy to grow in
the classroom and they are large enough to see with bare eyes or a magnifying glass.
Research:
Research and complete source cards about :
1.
What is the ozone layer and how does it protect the Earth?
2. How are people damaging the ozone layer?
3. How does the ozone layer relate to sea life and plankton (brine shrimp)?
You must use at least one book, one reference book, one electronic database, and one
website as a source. Because all sources must be correctly cited at the end of the lab
report, make sure your source cards are complete. Staple your source cards to the back of
this lab paper.
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Write a paragraph about each of the three topics. Each paragraph must have at
least 5 sentences.
What is the ozone layer and how does it protect the Earth?
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How are people damaging the ozone layer?
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How does the ozone layer relate to sea life and plankton (brine shrimp)?
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Purpose: To determine if increased amounts of ultraviolet light cause brine shrimp to die.
Hypothesis: ________________________________________________________________
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Experiment:
Materials:
1. Hatched brine shrimp
2. Sunscreens: SPF 8, 15, and 30
3. 4 Large petri dishes
4. 1 transfer petri dish of brine shrimp
5. Saltwater
6. Eyedropper
7. Magnifying glass
8. Graduated cylinder
9. Sharpee
10. Sunny window sill or artificial ultraviolet light source
11. Graph paper
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Procedures:
1. Take five large petri dishes and label them one through five on the top cover using the
sharpee. Make sure this number is not too large, just make it big enough to tell the dishes apart.
On the bottom of each dish, write your name(s).
2. Using the graduated cylinder, measure and pour 30 milliliters of saltwater into each of the
petri dishes.
3. From the transfer petri dish of "brine shrimp", carefully count out and place 10 live (moving)
"brine shrimp" into each of the 4 petri dishes (that is, 10 shrimp per petri dish). Note this amount
on the data table under day 0.
4. Using a finger, smear the top cover of petri dishes 2 - 4 with sunscreen (about the size of a
pea). Refer to the information below to see which sunscreen to smear on which dish. Make sure
the same amount of sunscreen is placed on each cover. It should leave a transparent film on
the petri dish after it dries.
Petri dish #1:
Petri dish #2:
Petri dish #3:
Petri dish #4 :
None
SPF 8
SPF 15
SPF 30
5. Place the dishes on a sunny window sill so that they can be exposed to ultraviolet light. All
the dishes should receive the same amount of sunlight. Do not stack the dishes on top of one
another and check to make sure they aren't getting too hot from the sun. An artificial ultraviolet
light source may be used instead of a window sill.
6. Two days later, count the number of live "brine shrimp" in each plate by using a piece of
graph paper as a grid. Place each of the dishes on top of the graph paper and count the number
of moving or live "brine shrimp" remaining. A magnifying glass may be needed for this step.
Record the results on the data table. Calculate the average number of living brine shrimp in
each petri dish for the class. Include the data tables in the final lab report.
Experimental Group: ______________________________________________________
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Control Group: ___________________________________________________________
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Constants: _______________________________________________________________
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Independent Variable: ______________________________________________________
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Dependent Variable: _______________________________________________________
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Results:
Number of Live "Brine Shrimp" for Group
Data Table
Petri Dish #1
No
Sunscreen
Petri Dish #2
SPF 8
Petri Dish #3
SPF 15
Petri Dish #4
SPF 30
Day 0
Date: _____
Day 2
Date: _____
Average Number of Live "Brine Shrimp" for Class
Data Table
Petri Dish #1
No
Sunscreen
Petri Dish #2
SPF 8
Petri Dish #3
SPF 15
Petri Dish #4
SPF 30
Day 0
Date: _____
Day 2
Date: _____
7. Make the following graphs from the class data tables.
A. Bar graph showing the number of living brine shrimp for each sunscreen s.p.f. number.
B. Line graph showing the number of living brine shrimp compared to the sun
protection factor.
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Conclusion:
According to the results of the experiment, the hypothesis was _________, _____________
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Discussion questions that can be used to write additional information for your
conclusion :
1. Which petri dish had the most surviving "brine shrimp"?
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2. Which petri dish had the least surviving "brine shrimp"?
3. According to the graphs, what is the relationship between the S.P.F. of the sunscreen
and the number of surviving "brine shrimp"?
4. According to this lab, how does ultraviolet light affect "brine shrimp"?
5. Was the hypothesis true or false and why?
6. If the ozone layer continues to thin, what can you predict will happen to the organisms
which live close to the surface of the ocean such as plankton ("brine shrimp")? How will
this affect the food chain?
7. Based on the results of this lab, what actions should we take as a community?
Write a formal lab report using the information from this lab sheet. Resources are available at
http://www.artisandevelopers.com/web/razorbacks/sciencelinks.htm.
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