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 ᵒC, bright light, and forceps.
VARIABLES
VARIABLES
WAYS TO MANIPULATE
MANIPULATED:
Vary the temperature of the salt solution such
The temperature of the salt solution.
as 22 ᵒC, 29 ᵒC and 32 ᵒC.
RESPONDING:
Calculate the rate of hatching success of the
Rate of hatching success of the brine shrimps.
brine shrimps using formula
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 22ᵒC.
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 29ᵒC and the other one was put in the water bath of 32ᵒC.
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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
Average
2%
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
𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒆𝒈𝒈𝒔 𝒉𝒂𝒕𝒄𝒉𝒆𝒅
Rate of hatching success = 𝒕𝒐𝒕𝒂𝒍 𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒆𝒈𝒈𝒔 (𝟓𝟓) 𝒙 𝟏𝟎𝟎%
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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
Rate of hatching success / ᵒc
60
54,4
50
40
40
1 % salt solution
32,7
2 % salt solution
29,1
30
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 =
𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑒𝑔𝑔𝑠 𝑡ℎ𝑎𝑡 ℎ𝑎𝑡𝑐ℎ𝑒𝑑
𝑡𝑜𝑡𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑒𝑔𝑔𝑠
𝑥 100%. 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 22ᵒC, 29ᵒC and 32ᵒC as temperature is
set as the manipulated variables. These temperatures are obtained by putting the boiling tube in
the water bath of 32ᵒ, keep in the store room for temperature of 22ᵒC and lastly placed on the
bench of the laboratory to get temperature of 29ᵒC which is the room temperature. Meanwhile
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 29ᵒC has the
highest number of eggs hatched which is 37/55 with the success rate of 67.3%. This followed by
temperature of 22ᵒC with the percentage of 54.4% and the lowest number of eggs hatched is at
temperature 32ᵒC with the percentage of 29.1%. So, brine shrimp need an optimum temperature
of range 25ᵒC to 30ᵒC to hatch and temperature that is too high will inhibit the hatching process
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 22ᵒC, 29ᵒC and 32ᵒC.and were kept for overnight to give the time for the eggs to hatch. The
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 29ᵒC is more likely
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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