Activity 1.1.1

Modeling Krill Behavior:
How do brine shrimp react to physical stimuli?

Materials (for each group of 3/4 students):

• microscope or hand lens
• brine shrimp eggs
• plastic bag
• light source
• petri dish
• ice cubes
• cover glass and slide
• salt
• water
• aluminum foil
• glass rod
• graduated cylinder
• balance
• medicine droppers
• bar magnet
• Activity 1.1.1 Student Worksheet
  

Procedure:

1. Make a salty ocean for brine shrimp to swim in by adding 3.5 grams pure (not iodized) sodium to 1,000 milliliters of water. (3 or 4 tablespoons salt in a gallon of water)
   
2. Fill a petri about half way with the salty water to make a fish bowl for the eggs.
   
3. Touch one end of a glass rod to the salt water to dampen it and then touch the dried brine shrimp. The damp rod will pick up a bunch of eggs. Transfer eggs to the petri by stirring the rod end through the solution in the petri. Cover the petri dish.
   
4. Look at the eggs through magnification every 24 hours and carefully draw their appearance. When you have lots of brine shrimp swimming around, you are ready to conduct experiments.
   
   Brine Shrimp Observations:
   
   

   Day	Day	Day
   Day	Day	Day

   
   
5. Fill two eyedroppers with crowds of brine shrimp.
   
6. Wrap aluminum foil around one eyedropper to prevent light from entering. Leave 5mm at the tip free of foil.
   
7. Hold both eyedroppers near a light bulb for at least ten minutes without moving them. Where do the brine shrimp go in each eyedropper? (Be careful not to let the eyedroppers get hot.) (effect of light)
   
   
   
8. Squirt the brine shrimp back into the petri dish and get new samples of brine shrimp in each eyedropper.
   
9. Set one eyedropper horizontally on a large ice cube and prop the other horizontally on your lab table for at least 5 minutes. What response do you see? (effect of temperature)
   
   
10. Squirt the brine shrimp back into the petri and get new samples of brine shrimp in each eyedropper.
    
11. Hold one eyedropper vertically and the other horizontally for two minutes. Do you observe a difference in brine shrimp behavior? (effect of gravity)
    
    
12. Set one eyedropper horizontally on a magnet and hold the other horizontally for two minutes. What response do you get? (effect of magnetism or geomagnetism)
    
    
    Conclusions:
    
    Which stimuli appeared to have the most effect on the behavior of brine shrimp?
    
    
    How might your observations be applied to the movements/habits of krill in the oceans around Antarctica?
    

Student Worksheet #1.1.1

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