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MODEL LESSON #1 Artemia: The Brine Shrimp

 

To study the effects of the environment on hatching and activity of brine shrimp, Artemia species combining ideas of physics, chemistry and biology. To use the Artemia as a test organism to assess water quality. To design and carry out experiments to answer questions such as: Are Artemia affected by the chemistry of their environments? Are Artemia affected by light? Are they affected by temperature?

Objective:

To compare hatching of Artemia eggs in different fluids: (1) water; (2) water at low pH; (3) sea water or 2% sodium chloride solution; (4) same as (3) except at low pH.

Procedure:

Students should work in pairs. Each pair of students should have 3 petri dishes, to test water only; salt solution; and either acid water or acid salt solution, according to the students' preferences.

Place enough fluid in each dish to form a layer about 1 cm deep. Shake a small quantity of Artemia eggs onto the surface of the fluid. Look at the eggs with the microscope. Cover the dish (to prevent excessive evaporation; the oxygen supply must not be cut off). Maintain the dishes at room temperature. Using the microscope, check for any changes over the next few days.

Observe the Artemia hatchlings. Do they respond to light? try covering a dish with aluminum foil, then removing the cover and looking quickly to see where the Artemia are swimming; or shine a light on only one part of the dish, while the rest is covered with aluminum foil.

Record observations; draw sketches of Artemia eggs and hatchlings (they are easier to draw if they are cold). Compare conditions and hatchlings; for example, use a scale such as +++ = many +=few 0=none.

It is possible, though difficult, to count surviving hatchlings vs. eggs though we do not recommend this procedure.

Extensions:

Students can design and carry out tests to answer questions such as these, or others that they may have: What concentration(s) of salt solutions are best for Artemia hatching? Does temperature affect hatching? Can Artemia see red light? blue light? How long can Artemia live in these simple fluids?

The crucial role of energy in life can be introduced here:

  • Where do Artemia get the energy needed for swimming?
  • Why do they not go on living in these simple fluids?
  • What conditions would make possible growth and survival of Artemia?
  • Do Artemia hatchlings and radish seedlings obtain energy in the same way?
Evaluation:

Evaluation should be based on activities and ideas presented by the students, such as:

  1. journals describing the results.
  2. ideas about other conditions that might affect Artemia.
  3. experimental designs to test ideas in (2).
  4. reports in which all the students compare their results.
  5. suggestions as to where Artemia may be found in the world, and why.
Resources:

Artemia eggs are supplied by aquarium, tropical fish, or pet stores, and by biological supply companies:

  • Carolina Biological Supply Company, 2700 York Rd., Burlington, NC 27215 1-800-334-5551
  • Ward's, PO Box 92912, Rochester, NY 14692-9012 1-800-962-2660
A lifetime supply (they can be kept indefinitely in dry form) costs less than $ 5.00.

Disposable petri dishes (preferably 100x15 mm) can be obtained from the suppliers listed above, or from local suppliers of biological/medical materials and equipment. Petri dishes are fairly expensive (e.g., 100 for $20, from Carolina Biological. Supply.) but they can be washed carefully and used over and over again (even though they are designated as "disposable").

 

©Rural Girls in Science- Meeting the Challenge Through a Comprehensive Approach
funded by the National Science Foundation Project HRD-94500053
Dr. Angela B. Ginorio, Principal Investigator

Rural Girls in Sciene Program
rural@u.washington.edu
Imogen Cunningham Hall Box 351380
University of Washington
Seattle, WA 98195 (206) 543-7476 FAX (206) 685-4490