|Lesson 3-Determining the Effects of a pH Change on
the Hatching and Development of Brine Shrimp Eggs.
1. Brine shrimp eggs may be purchase from a scientific
supply company or at a local pet supply store.
2. Brine shrimp culture should be made 24 hours in advance
and can be kept indefinitely, if fresh salt water is added on a continual
3. The common brine shrimp (artemia) are closely related
to zooplankton such as Daphnia and are often used as live food for aquariums.
The artemia life cycle begins by the hatching of dormant cysts 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.
Other variables of importance are pH, light and oxygen.
A pH of 7.5-8.5 is optimal, and can be lowered with muriatic acid (any
type of acid may be used) or increased with baking soda. A minimum amount
of light is necessary for hatching and is beneficial for increased adult
Two liter soda bottles with the tops cut off and filled
with tap water make great hatching containers. To the bottle filled with
water add 10 to 20 grams of salt without iodine and a pinch of sodium bicarbonate
(baking soda). Test the pH to make sure in stays in a range of 7.5-8.5.
Aeration is necessary and can be accomplished by a small air pump with
a length of tubing long enough to reach the bottom of the bottle. Aeration
should be light, as the eggs will not hatch if aeration is too brisk.
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.
1% NaOH - To make 1 liter of this reagent, weigh out 1
gram of NaOH. Add the NaOH to 999 milliliters of distilled water. Store
in a capped bottle. Invert and mix before use. Put in labeled dropper bottles
for use in this lesson.
1% HCl - To make 1 liter of this reagent, add 1 milliliter
of 1M HCl to 999 milliliters of distilled water. Store in a capped bottle
in an acid cabinet. Put in labeled dropper bottles for use in this lesson.
Note: Safety goggles and aprons should be worn
at all times when mixing reagents. When working with acids, reagents should
be made in a exhaust hood.