Introduction: (Initial Observation)
Brine shrimp are tiny – just 10 millimeters long – but they’re a huge part of the salt pond ecosystem.
The tiny brine shrimp are a nutritious food for many birds and fishes. Those who have an aquarium at home may have experienced growing brine shrimps.
Because of the importance of brine shrimps in echo system and the need to grow them, it is important to learn about the conditions necessary for their life.
In this project you will grow brine shrimp in different environmental conditions including light, temperature and water salinity. Use the results of your experiments to draw a conclusion and prepare your report.
Gather information about brine shrimp, it’s life cycle, it’s uses and it’s habitat. Read books, magazines or ask professionals who might know in order to learn about the effects of different environmental conditions on brine shrimp. Keep track of where you got your information from.
The following Websites offer good resources for Brine Shrimp:
Brine Shrimp and the Ecology of Great Salt Lake has information on how brine shrimp live in Great Salt Lake and how they are harvested there.
Brine Shrimp Life History has wonderful photographs of the life cycle of brine shrimp, most taken at high magnification.
While gathering information from books or from the Internet, note that Brine shrimp are also called “Sea Monkeys” and are raised in aquariums for their entertainment value. Following are some sample information that I have gathered about brine shrimp.
Brine Shrimp Classification:
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 re-hydrated 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 or increased with baking soda. A minimum amount of light is necessary for hatching and is beneficial for increased adult growth.
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).
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.
Any of the following questions can be the subject of a science project and an experiment related to brine shrimp eggs or live brine shrimp.
Brine Shrimp Eggs:
- Does temperature affect the rate at which brine shrimp eggs hatch?
- Do different concentrations of salt affect the rate at which brine shrimp hatch?
- Does increased acidity (acid rain) affect the hatching rate of the brine shrimp?
- Do increased amounts of light increase or decrease hatching rates?
- Do pollutants (oil, etc.) have an effect on hatching rates?
Live Brine Shrimp:
The same problems may be investigated using live brine shrimp, but determinations can be made on mortality rates.
- What amounts of food are optimal for brine shrimp survival?
- What is the optimal salt concentration for brine shrimp survival?
- Can brine shrimp survive at temperatures which are less than optimal (storage in the refrigerator, etc.)?
Larval Development of Brine Shrimp
Before reaching adulthood, brine shrimp go through 15 larval stages which are called Instar 1 to Instar 15. The newly hatched baby brine shrimp is called an “Instar 1 nauplius”. It does not need to be fed yet as the nauplius lives on it’s yolk reserves which it got from the egg (cyst). After about 6 to 8 hours (depending on the temperature), the yolk-sac is depleted and the mouth and anus of the nauplius have opened and the animal can start feeding itself now. At this time however, mortalities can occur as bacteria start “invading” the nauplius through the mouth and the anus. Some of the nauplii do not survive this “invasion”. In order to limit the damage done to the culture, it is important to harvest the nauplii from the hatching container and rinse them well. During the hatching process, glycerol is being released into the hatching medium as the brine shrimp cysts start bursting. This glycerol forms a perfect feeding ground for bacteria, which were already present in the hatching medium as large amounts of
bacteria are always present on the brine shrimp cyst shell.
Feeding of Brine Shrimp
Brine Shrimp are continuous, non-selective filter feeders, which means that they actually don’t care about what they eat. They just filter particles like micro-algae, bacteria and detritus from the water using the feather-like appendages on the pleiopoda. These appendages continuously filter particles from the water and transport it to a groove located on the ventral side (belly) of the brine shrimp. Very fine hairs in this groove transport the food to the mouth where it is ingested.
Because they feed continuously, the food should be continuously added to the water column in the grow-out tank. The trick is to prepare the food into a solution (with light aeration) and drip the solution into the grow-out tank.
As brine shrimp have a very small mouth, they can not feed on food particles bigger than 50 micrometers (i.e. 0.000050 m). This is the reason why the food needs to be “micronized”. You can prepare food to this size by obtaining a piece of 30 micrometer filter netting from a scientific goods supplier and sifting the food through the net. Another way is to use a kitchen blender when making the food. Blend thoroughly and for at least 5 minutes. Sieve it afterwards through the aforementioned fine mesh sieve or squeeze it through a handkerchief.
Potential feeds for brine shrimp include:
- Micro-algae: the best food for feeding your brine shrimp. Suitable species include: Tetraselmis, Nannochlo-ropsis, Isochrysis, Chaetoceros, and others. Though a little expensive to start up and very labor consuming, rearing algae is not that difficult. For the seriously interested, you might succeed in acquiring some starter cultures from universities. Manuals on growing algae yourself will be available in the near future from our company. You can either choose to culture live algae yourself, or buy algae paste from your local health food shop. Most of these dried algae, however, contain a high amount of water soluble proteins which can not be taken up by brine shrimp. Though sometimes expensive, algae (paste) is well worth the extra effort as they form a superior food compared to the feeds mentioned below dueto their high levels of Highly Unsaturated Fatty Acids (HUFAs). Another advantage of using live algae is that algae are thought to release substances into the rearing medium which act as natural antibiot
ics which can suppress unwanted bacterial growth.
Note: in order to get rid of soluble proteins (which can not be taken up by the brine shrimp but will be used by the bacteria present in the culture), you can suspend the dried algae in a container, mix well with a kitchen blender, aerate the mixture for about 90 minutes, leave it to settle and decant the solution. Only use the matter settled on the bottom to feed the brine shrimp.
- De-fatted and micronized rice-bran: Again, suspend the rice bran in some salt water and mix well with a kitchen blender. It must be noted that this food contains a high amount of fibers.
- Brewer’s yeast (Saccharomyces albicans): although ready available, easy to use and digestible for brine shrimp, the nutritional composition of this yeast is far from optimal. Do not use it as a main diet!
- Home-made feeds: Many people have developed their own home-made recipe for feeding their brine shrimp over the years. Most of them contain a mixture of: egg (yolk), fish meal, cod oil, soy meal, wheat and cottonseed meal (enriched with lysine)
Note on soy meal: in the aquaculture industry soy meal is enriched with methionine and lysine, essential amino acids lacking in soy meal. Another disadvantage of (non-heated) soy meal is that it contains trypsine inhibitors, which can limit performance, and that it contains a high amount of water soluble proteins.
- Chicken Manure: very well suited for brine shrimp… though your family members might be less than thrilled about it … Chicken manure is used all over the world where people grow brine shrimp in rice ponds or solar evaporation fields. The manure should be fresh, white and wet, and not contain earth or hay or whatever is used to collect the manure. Put some manure in a bucket or container and stir/mix well. Let this solution drip in your grow out tank. The manure is not only consumed directly by the brine shrimp, but also contains bacteria which can be eaten by the brine shrimp.
How much food to feed brine shrimp?
- As aforementioned, a continuous drip-feeding should be provided. When not possible, a daily feeding schedule of 4 to 6 times should be followed. When to feed? This is where a Secchi-disc comes in handy. A Secchi-disc is a plastic (e.g. the lid of a plastic jug) or wooden disc on which 2 perpendicular lines are drawn. Two shranked surfaces are painted black, the other 2 are painted white. Perpendicular to the disc surface, a stick is attached to the disc so the disc can be lowered and raised in the tank, parallel to the water surface.
How to use a Secchi-disc?
- Gently lower the disc in the water, keeping the disc surface parallel to the water surface, until you cannot distinguish the difference anymore between the white and black areas. Hold the disc and note at which depth the disc is. Slowly move the disc up until you can distinguish both colors again. Note this depth. Figure the average of these 2 measurements – this average is the Secchi-reading. A reading of about 20 cm should be recorded. This level of turbidity should provide enough food for the brine shrimp. Of course, this is only a general rule. After a while you will notice which Secchi-reading is most optimal for the brine shrimp in the conditions you keep them in. Secchi Disk is available at MiniScience.com.
- If you own a microscope you can check the gut or digestive tract of the brine shrimp. You should be able to see food particles packed in the digestive tract. You can also use a strong magnifying glass and examine the brine shrimp which are put on a piece of glass under which a light source is installed. When you can’t distinguish food particles in the tract, too little food is present in the rearing tank. A completely filled tract is also not desirable as the ingested food might leave the digestive tract without actually being digested. Remember that brine shrimp are feeding continuously, they do not know the feelings “hungry” and “I’m full”. So when too much food is present, the food may just pass the tractus without being digested, and the brine shrimp will die from starvation!
- Yet another thing to watch are their fecal pellets – they should be firm and compact. If they are not, more than likely you do not provide enough food.
- When starting, make sure to start with a disinfected tank so as to limit the amount of bacteria present in the tank.
- Brine shrimp are euryhaline animals, which means that they are tolerant of a wide range in salinity, e.g. from about 5 ppt. to around 220 ppt. However, in order to reduce the amount of osmotic stress the brine shrimp are subjected to, we should keep them in a salinity of about 25 to 40 ppt. The exact salinity is of minor importance, just keep it around this level. To keep things simple (though scientifically not exact): 35 ppt. means 35 g of salt dissolved in 1 liter of water (or about 4.7 oz. in 1 gallon). Make sure that the salinity of the hatching medium is the same as the salinity in your grow out tank; in this way the nauplii will not have to bridge a salinity shock.
- A pH ranging from 8 to 9 is most optimal for brine shrimp. This is the pH of most of the salt lakes and solar evaporation ponds that brine shrimp naturally occur in. As pH will slowly drop during cultivation (due to the release of waste products and subsequent nitrification) you will have to perform water changes and/or enhance the buffer capacity of the medium by administering technical grade NaHCO3 (until 2 g per liter). Do not use Na2CO3 as this increases pH to above 9!
- Brine shrimp can tolerate a wide variety of temperatures, however, a temperature ranging from 20°C to 30°C (68 F to 86 F) is most optimal. Also keep in mind that the optimal temperature for reaching the highest reproduction rates for brine shrimp is strain specific! For example, in order to achieve highest reproduction levels for Artemia franciscana (SF-strain) a rearing temperature of around 24° C (75 F) is optimal. At the lower range (i.e. 20°C and lower) A. franciscana (SF-strain) grows slower, is less active, requires less food, achieves higher food conversion rates and lives longer. But the reproductive period is shorter and total offspring is much smaller. At the higher end they will be more active, require more food or energy, have less broods and live shorter (Browne, Davis and Sallee, 1988).
- A moderate aeration should be installed to keep the amount of dissolved oxygen at level (around 4 to 5 mg O2 per liter) as well as to keep the administered food suspended throughout the water column. Very well suited for this purpose are air-water-lifts, though aeration lines can be used as well, provided the produced bubbles aren’t too small. Very red colored brine shrimp are a sign of low oxygen levels, whilst pale, blue to green brine shrimp (depending on the food they are consuming) indicate medium to high oxygen levels. When oxygen becomes limited, brine shrimp react by producing hemoglobin molecules, which enables them to “absorb” the dissolved oxygen still present in the medium. Another thing to watch is that you should be careful NOT to produce air bubbles that are too small. These small bubbles may get stuck between the thoracopoda (“legs”) of the brine shrimp seriously hindering food uptake and carrying the brine shrimp to the water surface where they will be helpless!
Note: Whilst not proven, it is suspected that pale brine shrimp are less attractive to fish.
Do not provide too much light as this might be counter-productive. A few installed standard light bulbs are okay. In nature, adult brine shrimp will move to the deeper parts of the ponds during noon (period with highest light intensity). In contrast to the nauplii which are positive phototactic (attracted to light), adult brine shrimp are negative phototactic (move away from light sources).
Baby brine shrimp are much more sensitive to poor water quality as compared to adult brine shrimp. Therefore high levels of ammonia and nitrites should be avoided. Controlling water quality can be accomplished through a combination of biological filtration, frequent water changes and siphoning out of dirt settling on the bottom. When doing a water exchange, siphon the water out of the tank into a fine mesh net which is submersed in a bucket. Simply catch the brine shrimp in the net as you are siphoning out the water, lift the net with the rising water level and the brine shrimp will keep on swimming in the net. Return the brine shrimp immediately to the grow-out tank afterwards.
The outlet from the growing tank to a biofilter should be screened with a fine mesh of around 200 micrometer. As it will clog up, it will need to be cleaned regularly. As the brine shrimp increase in size, the mesh size should also be increased.
How many Brine Shrimp to Start With?
Try to start with a maximum density of about 5,000 nauplii per liter culture medium.
Browne, Davis and Sallee, 1988. Effects of Temperature and Relative Fitness of Sexual and Asexual Brine Shrimp Artemia, J. Exp. Mar. Biol. Ecol., 1988, Vol. 124, pp. 1-20.
Brine shrimp (Artemia franciscana) are tiny – just 10 millimeters long – but they’re a huge part of the salt pond ecosystem.
Brine shrimp thrive in salt ponds where salinity measures 80 to 190 parts per thousand (8 to 19 percent), where there are plenty of algae to eat and few predators and competitors. The tiny brine shrimp nourish migrating birds during their flights up and down the Pacific Flyway; they are also favorite fare for dozens of resident species, which frequent the ponds year-round.
Some of the birds dining on brine shrimp, in turn, end up as prey for the raptors that patrol the salt ponds: peregrine falcons, hawks…even an occasional golden eagle.
What do you want to find out? Write a statement that describes what you want to do. Use your observations and questions to write the statement.
To design and conduct a laboratory investigation to determine how different factors may affect the hatching and development of brine shrimp eggs as well as growth and survival of brine shrimp.
When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.
Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis.
Since we have proposed many different questions, one hypothesis is required for each question. So for now, I include the hypothesis is the experiment section.
Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”
All brine shrimp experiments require having brine shrimps and brine shrimp cysts (eggs). So find and buy some eggs.
Where to buy eggs?
Upon hatching, brine shrimp make an excellent source of live food for baby and adult tropical and marine fish. These eggs usually come from salt ponds that are rich in algae and diatoms.
Since brine shrimp is used as a fish food, you may purchase brine shrimp eggs from pet stores that also sell fish, aquarium and other fish related products. You may also buy brine shrimp eggs online. I have seen it in Petdiscounters.com. A 6 gram vial sells about $4.00
Experiment 1: The effect of temperature on hatching and development of brine shrimp
This is not the main experiment of this project, however since you need to hatch some eggs and grow some brine shrimps for your main experiments, you can also study on the effects of temperature on the hatching and development of brine shrimps.
Purpose: To investigate the effect of temperature variations on hatching and development of brine shrimp.
Hypothesis: Temperature will have an effect on hatching of brine shrimp and the optimal temperature for hatching will be 27ºC.
Introduction: Brine shrimps are small, halophytic crustaceans. They remain in a cyst form until favorable conditions arise. Once in favorable conditions, hatching occurs after 24-36 hours.
Under ideal conditions, the shrimp will grow to an average adult length of 8mm and will live for approximately 3 months. Brine shrimp is often used for fish food and marketed commercially as “Sea Monkeys”
- Measure 3 grams of instant brine shrimp mixture (Brine shrimp mixture contains both the food and the eggs)
- Mix salt with distilled water (or aged tap water) until reaching 35ppt salinity
- Add shrimp mix to 1000 ml of prepared water
- Divide your mix in 10 identical parts (100 ml each). Setup samples for 5 different temperature environments in duplicate (total of 10 samples, two samples for each temperature). Temperatures to test: 6, 12, 20, 27, 32ºC
- Cover beakers with aluminum foil
- collect data twice daily by examining 4 ml sample under dissecting scope or magnifying glass and count the number of shrimp hatched.
- Count the number of hatchings present in a 4ml sample twice a day.
If your experiment failed, check the followings:
- Insufficient surface area for oxygen absorption
- Exposure to light or other environmental factors (cover your samples/ flasks)
- Insufficient or no food provided
Make observations and include in your results:
The count of hatched shrimps in each temperature. The physical appearance of shrimps (color, length, movements, …)
Watch for possible errors:
- Sample size inequality
- Estimation error/ Experimenter bias
- sampling bias
- Contaminated sample
- Imprecise measuring equipment
How to create different temperatures:
If it is winter and the weather is cold, aquarium heaters can be used. Otherwise you need to find different temperature environments at your home. If you have a cold room and a small electric heater, you may setup your samples in different distances from the heater. The one that is closer will have the higher temperature and the one that is the farthest, will have the lowest temperature. If you do this you need to do some initial experiments with just water and find out what will be the temperature of different containers placed in different distances from the heater.
Experiment 2: In this experiment I want to see if light is necessary for the life of brine shrimps.
Although you can perform many experiments with brine shrimps, this is one of the main experiments for this project. Before starting this experiment, grow some brine shrimps.
Procedure: Prepare six identical containers with equal amounts of brine shrimps in each container. Label two containers with the word “Dark”, two containers with word “natural light” and two containers with the word “Light”.
Place two containers that are labeled dark, under a carton box. Place the containers labeled natural light in the room and close to a window. These two containers will have daylight during the day and no light at night. Place the last two containers under a continuous fluorescent light.
Control the temperature and other environmental factors such as water type, water pH and water salinity. Feed the shrimps with the same amount and the same type of food.
Make daily observations and record the number of dead brine shrimps for two weeks. At this time, you may also remove dead brine shrimps.
Record the results of your experiment in a table and use that for your analysis and drawing conclusion.
Number of dead shrimps in different categories
|Date||Dark 1||Dark 2||Natural 1||Natural 2||Light 1||Light 2|
Experiment 3: In this experiment I want to see if salt is necessary for the life of brine shrimps.
Procedure: Prepare six identical containers. Label two containers with the word “water”, two containers with word “low salt” and two containers with the word “high salt”. For the containers labeled water, use spring water with no added salt. For the low salt container use a 15% salt solution. For the high salt containers use 30% salt solution. Place equal amounts of brine shrimps in each container and keep them at room temperature and room light.
Feed the shrimps with the same amount and the same type of food.
Make daily observations and record the number of dead brine shrimps for two weeks. At this time, you may also remove dead brine shrimps.
Record the results of your experiment in a table and use that for your analysis and drawing conclusion.
Number of dead shrimps in different categories
|Date||Water 1||Water 2||Low salt 1||Low salt 2||high salt 1||high salt 2|
You can use similar experiments to test other factors. For example you may want to know if air is necessary for the life of brine shrimp. You may design a similar experiment and use a glass jar filled with water and seal the cap, while other jars are open.
I also suggest reading about decapsulating brine shrimp eggs:
Materials and Equipment:
List of material can be extracted from the experiment section. This is a sample:
- brine shrimp cysts (eggs) or Brine Shrimp mixture (eggs and food)
- Gram scale
- Measuring Cylinder or measuring cup
- Aquarium heater and thermometer
Results of Experiment (Observation):
Experiments are often done in series. A series of experiments can be done by changing one variable a different amount each time. A series of experiments is made up of separate experimental “runs.” During each run you make a measurement of how much the variable affected the system under study. For each run, a different amount of change in the variable is used. This produces a different amount of response in the system. You measure this response, or record data, in a table for this purpose. This is considered “raw data” since it has not been processed or interpreted yet. When raw data gets processed mathematically, for example, it becomes results.
No calculation is required for this project.
Summary of Results:
Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.
It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.
Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.
Related Questions & Answers:
What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.
If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.
If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.
List of References
Sample Project: http://www.selah.wednet.edu/SOAR/SciProj99/ShariSciProj.html
How to hatch brine shrimp eggs?
Another source (maybe wholesale) for brine shrimp: http://www.jehmco.com/