Brine Shrimp Facts

The Brine Shrimp Project

Name: ______

Purpose:

To design and conduct a laboratory investigation to determine how different factors may affect the hatching and development of brine shrimp eggs.

Introduction:

The Brine Shrimp Project is an investigation in which you and your partner will gather and analyze data about how different factors may affect the hatching and development of brine shrimp. In addition, all students will have the opportunity to design an experiment, conduct an investigation using the scientific method, analyze the results and share the results with the rest of the class.

Brine Shrimp Facts

The brine shrimp lives in salt swamps such as those found inland of the dunes at the seashore, in man-made evaporation ponds used to obtain salt from the ocean, and in salt lakes such as those found in the desert region of the western United States. Few other organisms can tolerate such a high concentration of salt as is found in these locations.

The common brine shrimp (artemia) are closely related to zooplankton such as Daphnia and are often used as live food for aquariums. The brine shrimp’slife cycle begins by the hatching of dormant cysts (eggs) which are encased embryos that are metabolically inactive. The cysts can remain dormant for many years as long as they are kept dry. When the cysts are placed in salt water, they are rehydrated and resume their development.

After 15 or 20 hours at 25 degrees C (77 degrees F), the cysts burst and the embryo leaves the shell. For the first few hours, the embryo hangs beneath the cyst shell, still enclosed in the hatching membrane. The embryo will grow and progress through 15 molts before reaching adulthood in approximately 8 days. Adult artemia average about 8mm long, but can reach lengths of 20 mm under ideal conditions.

Feeding the brine shrimp is necessary, if the culture is to be used for several days. A solution of baker's yeast and fish tank water to form a milky solution is an ideal food for the growing brine shrimp. The brine shrimp culture only needs a few drops of the yeast solution as they are not big eaters and overfeeding can foul the culture. The yeast solution can be placed in a dropper bottle and stored in the refrigerator.

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Answer the following questions using the information above:

1. Where can you find brine shrimp? ______

2. What are brine shrimp used for? ______

3. When does the brine shrimp’s life cycle begin? ______

4. How long does it take for the brine shrimp to reach adulthood? ______

5. What is the average length of an adult brine shrimp? ______

Scientific Method

Steps of the Scientific Method / Example from the Brine Shrimp Experiment
1. State a problem / Ask a question
- Using your five senses, make observations
about your natural world.
- From this information, figure out what you are
trying to solve!
Example: Does sunlight help plants grow?
Example: I wonder if sunlight helps plants grow.
2. Create a Hypothesis
- A hypothesis is a TESTABLE educated guess
or explanation for your problem.
- The hypothesis begins with “ I think that…”
OR – The hypothesis is an “If…. Then” statement
Example: I think that sunlight helps plants grow.
Example: If I put my plants in the sunlight, then they will grow more than without sunlight.
3. Test the Hypothesis - Experiment
- An experiment is the process of testing the
hypothesis by gathering data under
CONTROLLED conditions.
- Under controlled conditions, only ONE variable is changed.
4. Collect Data
- Keep track of information gathered by writing
it down in an organized manner.
- Analyze the data by graphing the information.
5. Make a Conclusion
- A conclusion answers the original question that
was asked.
- Was your hypothesis correct? If it was
incorrect, why?
Example: I thought that plants would grow more in the dark than in the light. My hypothesis was incorrect because my data shows that the plants grew more in the sunlight than in the dark.

Parts of a Controlled Experiment

Parts of a Controlled Experiment / Example from the Brine Shrimp Experiment
1. Constants
- are parts of an experiment that remain
unchanged
-For example, in the paper towel experiment,
the constants were:

marbles
coffee can
amount of water
elastic band

2. Independent variable
- is the part of the experiment that the scientist
changes
- there should only be one independent variable
- For example, in the paper towel experiment, the
independent variable was the brand of paper
towel - Bounty
3. Dependent variable
- is the part of the experiment that the scientist is
MEASURING
- responds to the independent variable
- For example, in the paper towel experiment, the
dependent variable was the number of marbles
it took to tear the paper towel
4. Control set up
- one part of the experiment in which the
conditions are normal
- the scientist has not altered the conditions with
the independent variable
- For example, in the paper towel experiment, the
control set up would be the coffee container
with the generic paper towel on it
5. Experimental set up
- one part of the experiment in which the
conditions
have changed by the scientist
- the independent variable is a part of the
experiment
- For example, in the paper towel experiment, the
experimental set up would be the coffee
container with the Bounty paper towel

Materials:

You will be provided with:

*pen

*masking tape

*a beaker or flask (to carry your salt solution)

* 200 mL 3% salt solution (50 mL per cup)

*4 cups for your samples - 2 per group in your experiment (control / experimental). 4 cups total.

* One light bank or shoebox (for your experimental group)

*1 blue scoop of brine shrimp eggs (see your teacher when your experiment is set up)

* 1 graduated cylinder

*4 pipettes (1 per cup)

* 2 petri dishes

* one stereo-microscope

Draw a diagram: You must draw a large of the set up of your experiment that includes all of your materials. Make sure you include the number of each cup (1, 2, 3, or 4), the amount of solution in each cup and what conditions each cup is placed in.

Procedure:

Day 2

Gather all materials.
Mark your cups with your names so you can tell which ones are yours.
Label each cup with a number 1 through 4
Write on cups 1-2: “Control Group”
Write on cups 3-4: “Experimental Group”
Add 50 mL of 3% salt solution to all cups
Have your teacher check your experiment.
Add 1 scoop of brine shrimp eggs to EACH cup. (your teacher has these)
Set your samples in a safe area

Day 3,4

Gather your samples (BE CAREFUL NOT TO SPILL!) and all materials needed
Using a pipette, stir CUP #1 so you can see the eggs and shrimp floating around in the cup.
Using the same pipette, extract ONE mL of brine shrimp solution from the cup and place into the petri dish.
Place the petri dish under the stereomicroscope and focus it so you can see the brine shrimp eggs.
Move the petri dish around underneath the microscope to see if there are any hatched eggs.
Record your data in data table #1 (number of eggs hatched (alive and dead shrimp). As long as they have hatched, record the # here).
Return the sample to CUP # 1.
Thoroughly rinse the petri dish with water (no soap!)
Repeat steps 12-18 for cups 2-4.
Clean up all of your materials properly and return your samples to the same area they were stored in before.

DATA TABLE #1: Effect of Light on the Hatching Rate of Brine Shrimp
# of Brine Shrimp Hatched Per Sample Each Day
Date: / Date:
Amount of Light / Cup # / Sample 1 / Sample 2 / Sample1 / Sample 2
Normal Amount of Light / 1 / 20 / 25 / 30 / 25
2
3
4
DATA TABLE #2: Calculations For Average # of Brine Shrimp Hatched In 100mL of 3% Salt Solution Per Group
Type of Light / Cup # / Avg. # of Shrimp Hatched Per Jar Per 100 mL Per Day / Avg # of Shrimp Hatched In 100mL of Solution Per Group
Normal amount / 1 / 25 / 30
2 / 35
3
4

Make a BARgraph of your average data (shaded boxes in data table 2) below.

Conclusion: Answer each question using full sentences.

1. Restate your hypothesis.

2. Do you accept or reject your hypothesis?

3. Give 3 facts from your data that support the hypothesis. Look at your tables and graph.

4. List 2 errors that were made or could have been made during the experiment.

5. If you had to experiment with brine shrimp again, what would you want to test?

6. In conclusion,

______.