Brine Shrimp Report

PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps TITLE: The Effect of temperature on the hatching success of brine shrimps

PROBLEM STATEMENT: What is the effect of temperature on the hatching success of brine

shrimps?

OBJECTIVE: To investigate the effect of temperature on the hatching success of brine shrimps.

INTRODUCTION Brine Shrimp

Figure 1: Brine shrimp

The scientific name for brine shrimp is

Artemia salina.

They are grouped in like their distant

cousins the lobster and crab. Brine is actually a salt solution which usually a saturated salt solution. Brine shrimp is also called fairy shrimp and sea monkeys because they are tiny but important organisms found in salt ponds and saline lakes. They are different from other aquatic crustaceans as brine shrimp live only in the salt water that is isolated from the ocean. They can be found in the Great Salt Lake in Utah and Mono Lake in California, but they can appear in temporary salt ponds after a torrential rain in the desert.

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PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps Brine shrimp are small unsubstantial-looking creatures with size approximately 1 cm (1/2") in length. They glide smoothly through the water, propelled by structures that appear to be two wings along their sides. When viewed under a microscope, the "wings" are revealed to be 11 pairs of appendages that undulate and act as paddles. As brine shrimp glide along, they feed on microscopic organisms suspended in the water such as algae, yeast, and bacteria. They generally consume a species of green algae called  Dunaliella because they are small, single celled and have a soft exterior which makes them easier to consume for the newly hatched shrimp. When there is too little or too much salt in the lake, the  Dunaliella become limited and the brine shrimp must eat the larger cells of the

diatoms,

golden brown algae, instead. These are

not the preferred food source due to their rigid cell wall of silica which makes them much more difficult to consume and digest, except for the older and larger brine shrimp. The green and golden brown algae are too large for juvenile brine shrimp to ingest, so they have found yet another food source. Life Cycle

Figure 2: Life Cycle of Brine Shrimp

The brine shrimp have a simple life cycle that is very well suited for the environment that they live in. There are both male and female brine shrimp. After mating, the female will develop

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PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps either live young or eggs in her egg sac. A female's first batch of young are born alive. After that, eggs form and are released into the water. Eggs may hatch soon thereafter, or they may lapse into a dormant or inactive state. The baby brine shrimp hatch in the spring from hard-shelled egg like spheres called cysts. These cysts were laid the previous fall and remained viable throughout the winter. Cysts are essential to the repopulation of the lake after the harsh winter. The eggs are amazing in their ability to completely dry out and maintain their viability. Brine shrimp eggs can lie in the desert for 10 years or more, waiting for the right environment, and then spring into life to start their life cycle again. After hatching from the cysts, the shrimp grow extremely fast. Juveniles possess only one eye, and adults develop two eyes. The majority of brine shrimp are females because the females are able to fertilize their own eggs without the assistance of the male brine shrimp. This method of  reproduction is called Parthenogenesis. However, towards the end of fall, males are required to produce over wintering cysts. The production of cysts requires sexual reproduction which means that males need to contribute sperm to the egg. This special adaption allows the brine shrimp to flourish in the Great Salt Lake and maintains genetic variability. After hatching, nauplius is formed which is the larval brine shrimp which looks like some tiny dark points in the water are making jerky little movements. The nauplius grows fairly rapidly when conditions are favorable with food, oxygen, and the right concentration of salt and molting its outer shell frequently. It takes 3 to 6 weeks for the shrimp to reach maturity. Brine shrimps are adapted to live in a wide range of salt concentrations, the lowest is 25 parts of  salt per 1000 parts of water and the highest is 300 parts per 1000 but their optimum salt environment is around 80 parts per 1000. This is more than twice as salty as the ocean, which is about 35 parts of salt per 1000. Brine shrimp are one of the most salt-tolerant animals in the world.

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PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps STEREOMICROSCOPE

Figure 3: Stereomicroscope

The stereo or dissecting microscope is an optical microscope variant designed for low magnification observation of a sample using incident light illumination rather than transillumination. It uses two separate optical paths with two objectives and two eyepieces to provide slightly different viewing angles to the left and right eyes. In this way it produces a threedimensional visualization of the sample being examined. The stereo microscope is often used to study the surfaces of solid specimens or to carry out close work such as dissection, microsurgery, watch-making, circuit board manufacture or inspection, and fracture surfaces as in fractography and forensic engineering. They are thus widely used in large numbers in manufacturing industry, both for manufacture, inspection and quality control. It tends to make them of lower cost compared with conventional microscopes. Stereo microscopes are relatively low power compared with compound microscopes, usually below 100 times. They can have a single fixed magnification, several discrete magnifications, or a zoom magnification system.

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PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps Global Warming

Global warming is the increase in the earth's average atmospheric temperature that causes changes in climate that is caused by the influx of human industry and agriculture in the midtwentieth-century to the present. As greenhouse gases such as CO2 and methane are released into the atmosphere, a shield forms around our Earth, trapping heat inside of our planet and therefore creating a general warming effect. One of the most influenced territories of warming is the oceans. Global warming apparently can affect many organisms include us, human also animals and plants. One of the effect is it causes the rises in the sea level due to the melting of ice in the North and South poles. When this happens, many aquatic organisms will be affected and many low-lying areas will experience flood. There are two general physical effects of ocean warming on marine populations that are crucial to consider:



Changes in natural habitats and food supply



Changing ocean chemistry/acidification

Besides that, global warming can affect the rate of photosynthesis of the plants because too high temperature can decrease the rate of photosynthesis as the enzymes responsible for photosynthesis may be denatured. When this occurs, many other organisms will be affected because plants are the primary source of food for the herbivore and for us too.

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PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps APPARATUS AND MATERIALS:

Brine shrimp egg cysts, salt water (1% and 2%), spatula, filter paper, stereomicroscope, boiling tube, 25 ml beakers, and distilled water, water bath at 32 C, bright light, and forceps. ᵒ

VARIABLES VARIABLES

WAYS TO MANIPULATE

MANIPULATED:

Vary the temperature of the salt solution such

The temperature of the salt solution.

as 22 C, 29 C and 32 C.

RESPONDING:

Calculate the rate of hatching success of the

Rate of hatching success of the brine shrimps.

brine shrimps using formula

ᵒ

ᵒ

ᵒ

no of eggs hatch total number of eggs FIXED: Volume of salt solution used

Fix the volume of salt solution used at 10 ml.

HYPOTHESIS: The higher the temperature of the salt solution the lower the rate of the

hatching success of brine shrimps.

NULL HYPOTHESIS:

Temperature has no effect on the success of hatching rate of the brine shrimps.

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PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps PROCEDURES 1. 10 ml of 1% of salt solution was poured into a beaker. 2. One spatula of the egg cysts was placed on a filter paper and the number of eggs were

counted using stereomicroscope with the range about 40-60 0f the eggs.

Figure 4: adjusting the stereomicroscope 3. The eggs were then poured into the beaker containing the salt solution. 4. The beaker was placed in the store room with temperature 22 C. ᵒ

Figure 5: Eggs at 22ᵒC 5. The same methods were then repeated twice. The first beaker was placed on the bench for

room temperature of 29 C and the other one was put in the water bath of 32 C. ᵒ

ᵒ

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PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps

Figure 6: Brine shrimp eggs that were kept in different temperature

6. The experiment was repeated by using 2% of salt solution. 7. The next day, the number of eggs hatched was counted by pouring the salt solution

containing the eggs into petri dishes and calculate under the microscope. 8. The data were recorded in the table.

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PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps

RESULTS

Number of eggs hatched Temperature

Concentration of salt solution / %

 / ᵒC

1% 1

2

3

2%

Average

Rate of 

1

2

3

Average

hatching

Rate of  hatching

22

37

36

38

30

54.4

14

12

11

12

21.8

29

32

28

30

37

67.3

16

19

21

18

32.7

32

15

18

15

16

29.1

22

23

21

22

40.0

Table 1

Rate of hatching success =

        ()

 

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PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps

Graph of Rate of Eggs Hatched against Temperature 80

70

67.3

60 54.4

      c        ᵒ

    /    s    s    e50    c    c    u    s    g    n    i 40     h    c    t    a     h     f    o30    e    t    a    R

40 1 % salt solution 32.7

2 % salt solution 29.1

21.8

20

10

0 22

29

32

Temperature / ᵒC

Graph 1: Rate of Hatching Success of Brine Shrimp Eggs

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PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps DISCUSSION

This experiment is conducted to investigate the effect of temperature on the rate of hatching of  the brine shrimp eggs which can be related to the global warming. This experiment is conducted to find out whether high temperature of the environment has effect to the aquatic crustaceans like brine shrimp. The hatching rate of the brine shrimp eggs can be calculated by counting the number of eggs that hatched after they are left overnight. The rate can be calculated by using the formula, rate of hatching success =

        

 . The higher the number of 

eggs hatched, the higher the rate of the hatching success. A range of temperature is used in this experiment which is 22 C, 29 C and 32 C as temperature is ᵒ

ᵒ

ᵒ

set as the manipulated variables. These temperatures are obtained by putting the boiling tube in the water bath of 32 , keep in the store room for temperature of 22 C and lastly placed on the ᵒ

ᵒ

bench of the laboratory to get temperature of 29 C which is the room temperature. Meanwhile ᵒ

the volume of 1% of salt solution used is kept constant at 10 ml to ensure the salinity of the water does not affect the result of the experiment. Besides, the brine shrimp eggs are counted under stereomicroscope to obtain an accurate and clear view of the eggs. From table 1, when the salt concentration is 1%, it is shown that the temperature of 29 C has the ᵒ

highest number of eggs hatched which is 37/55 with the success rate of 67.3%. This followed by temperature of 22 C with the percentage of 54.4% and the lowest number of eggs hatched is at ᵒ

temperature 32 C with the percentage of 29.1%. So, brine shrimp need an optimum temperature ᵒ

of range 25 C to 30 C to hatch and temperature that is too high will inhibit the hatching process ᵒ

ᵒ

of the eggs. However, eggs that do not hatch can still hatch because the egg cysts of brine shrimp are very resilient as it can withstand dry condition and they can hatch back when the condition is favorable. Optimum temperature is determined due to reason that highest number of egg cysts is hatched under this temperature. In order for an egg cyst to hatch, trehalose in the cysts has to be converted to glycerol. As glycerol is hygroscopic, water entering the cysts will burst the membrane and releasing the larvae. This is an enzyme-catalyzed reaction and enzymes are very sensitive to the temperature. When the temperature is optimum, the enzyme will work effectively

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PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps and the number of brine shrimps hatched is thus the highest. However, when the temperature is too high, the tertiary structure of the enzyme that catalyse this reaction will be denatured and results in less and no reaction take place because the active site on the enzymes surface is very highly specific and deterioration of the site will cause no reaction. In order to get a reliable result, the number of shrimps hatched is counted twice. The average value of three readings is calculated to minimize the errors in the counting. The result is also compared with the result of other group to ensure its validity. Besides that, there are ethical issues arise from the use of living organisms, which is brine shrimp for this experiment. Thus, proper disposal method has to be taken to dispose brine shrimps after the experiment so that it will not bring any unwanted consequences to the environment as well as the brine shrimps themselves. Hence, the increase in temperature that results in the global warming has greatly affected the aquatic crustaceans such as brine shrimps and especially their hatching rate. In the long-run, this may cause the number of these organisms to gradually declining because less and less eggs are hatched.

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PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps VALIDITY

This experiment is valid because it was conducted with the right method and apparatus used. Firstly, stereomicroscope is used to count the number of brine shrimp eggs. This microscope has a lower magnification than other microscope and we used magnification of 1.2 to see the eggs. After that, a suitable amount of salt solution with the concentration 1% is poured into the beakers and boiling tubes which measured by using measuring cylinder. Also, appropriate range of temperature were decided to be manipulated in this experiment which are 22 C, 29 C and 32 C.and were kept for overnight to give the time for the eggs to hatch. The ᵒ

ᵒ

ᵒ

same method also used to count number of eggs hatched and it is counted under bright light to avoid any errors. The methods used are suitable and hence the experiment is proven to be valid.

RELIABILITY

The results are compared with the other results in my class. It is shown that 29 C is more likely ᵒ

to be the optimum temperature for the eggs to hatch as it offers the highest hatching rate.

SAFETY PRECAUTIONS

When conducting experiment in the laboratory, lab coat must be worn as safety precautions. In this experiment, it is worn to prevent any spillage of the salt solution that can leave stain on the clothes. Besides that, the glassware should be handling with care because they are fragile and easily broken. When putting the brine shrimp eggs into the boiling tube, make that they are not stick to the wall of the tube. Swirl the boiling tube a few times to make sure that all the eggs are immersed in the solution.

LIMITATIONS AND WAYS TO OVERCOME

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PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps The first limitation is when counting the number of brine shrimps hatched from cysts correctly because the egg cysts and dead brine shrimps may be overlapping, causing the hatched brine shrimp very difficult to be seen. On the other hand, the hatched brine shrimps are also moving around the solution quickly and makes the counting process very hard and one brine shrimp may be counted for many times. This can be reduced by counting the eggs for three times, then find the average to minimize the errors. The second limitation is the amount of brine shrimp egg cysts is not the same for each boiling tube. In this experiment, about ½ spatulas of eggs cysts is added to the boiling tube. Therefore, the amount of the eggs added is not constant each time. Some boiling tubes have more eggs shrimps and thus higher probability of more brine shrimps hatched from the eggs in that boiling tube. However, this can be overcome as we calculate the rate of the hatching success, so the number of hatching eggs are dependent on the total number of the eggs.

SOURCES OF ERROR

When counting the number of the brine shrimps, there may be some errors occurs because the brine shrimp eggs may be overlapped and miscounting can happen due to human error. The same goes when counting the number of eggs that hatched as our eyes may be deceived when seeing the brine shrimp that are too small even though under the microscope. We may possibly count the reflection of the eggs or count the same eggs twice. This will affect the results later as number of eggs that hatched and the total number of eggs is taken into account to calculate the rate of hatching success. Furthermore, when transferring the salt solution, not all of the solution is poured into the boiling tube or beaker. Some of them may stick at the wall of the glassware and thus, reducing the total volume of the salt solution which was meant to keep constant in the experiment.

FURTHER WORK

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PRACTICAL 1: The Effect of Temperature on the Hatching Success of Brine Shrimps This experiment can be extended by changing the manipulated variable which is to study the effect of salinity on the hatching rate of the eggs. This can be done by manipulating the concentration of the salt solution such as 1%, 2%, and 3%. The procedure of the experiment will be same only that we need to change the manipulated and fixed variables.

CONCLUSIONS

http://en.wikipedia.org/wiki/Stereo_microscope http://www.martinmicroscope.com/MicroscopePages/Stereomicroscopes.htm

http://geography.about.com/od/geographyintern/a/globalmarine.htm http://en.engormix.com/MA-aquaculture/articles/global-climate-changes-on-aquaticenvironment-t2132/p0.htm

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