Investigation of effect of light
colours(red and blue) on the symbiosis relationship of Cnidarians and its
symbiodinium.
YEO ZHEN XI NAYTHAN, NG SHI YU student, THANGARAJA
Prasanna
Summary
We chose this topic as we went for an
overseas camp to learn about corals and wanted to find out more about the
symbiotic relationship between Cnidarians and its symbiodinium. The aim of this
project is to investigate the effects of different light colors on the
symbiotic relationship between Cnidarians and its symbiodinium. Our hypothesis
is that the Cnidarians exposed to blue light, it will have the most amount of
algae. The procedures of the experiment are as such: Algae clades were cultured
for 11 hours under light irradiation and harvested for the experiment. Sea
anemone (a form of Cnidarians) were then washed, incubated with the algae for 1
hour, and then washed again. Five samples of sea anemones were then placed
under blue and red light respectively. After 72 hours, we counted the number of
algae present in the sea anemone. Based on the results, we found that the ratio
of algae present in the sea anemone in blue light to red light is about 9 to 1,
which supports our hypothesis. This knowledge could lead us to the creation of
an engineering project. Sunlight usually cannot penetrate water deep enough for
corals and sea anemone to grow well beyond the euphotic zone. In order to
promote the growth of anemone, we can design a photovoltaic UV/blue light
delivery system to the corals on the seabed. This solution will increase the
growth rate of corals that will help create a healthier coral reef ecosystem.
Question / Proposal
After visiting aquariums for our Science
Learning Journey in Singapore and overseas, we were intrigued by the colors of
coral. The different light colors (blue and red) that cause the coral
(Pocillopora s) to glow differently. Then, we asked ourselves if the color that
the Cnidarians is exposed to will affect its growth.
We hypothesize that the sea anemone
placed under blue light will have more algae than the sea anemone placed under
red light. Our reasons for this hypothesis are as such:
Blue light has a shorter wavelength
(higher frequency) than red light so it contains more energy. Since algae
carry out photosynthesis to make food, we think that during the experiment,
the algae under the blue light will receive more energy and will thrive thus
reproducing faster. Thus, the results should show more algae present in the sea
anemone under blue light than red light.
The sea, where the corals and sea
anemone live is blue so we thought that Cnidarians and the symbiodinium in it
would also have adapted to photosynthesize using blue light.
Research
Light spectrum plays a key role in the
biology of symbiotic corals, with blue light resulting in higher coral
growth(NCBI, 2014). We wanted to find out more about the factors that affect
these cnidarians indirectly, which could have caused this phenomenon.
In many species of sea anemone,
additional nourishment comes from a symbiotic relationship with single-celled
dinoagellates, zooxanthellae or with green algae, zoochlorellae, that live
within the cells (Wikipedia, 2018a). In particular, this symbiosis promotes the
growth and survival of reef corals in nutrient-poor tropical waters; indeed,
coral reefs could not exist without this symbiosis (NCBI, 2014). More algae
would hence lead to more nourishment for the sea anemone, and thus let it grow
more.
The amount of energy in a light wave is
proportionally related to its frequency: High frequency (lower wavelength)
light has high energy; low frequency (higher wavelength) light has low energy
(HowStuWorks.com, 2000). The highest-frequency visible light would have to be
roughly blue (Socratic, 2015), and the color red has the longest wavelength of
the visible spectrum (NASA, 2018). This shows that they have the most and least
energy respectively. More light can mean more photosynthesis (UCSB, 2014), so
most and least energy would lead to the most and least rates of photosynthesis,
which in turn could affect the algae.
Another reason why we chose those
colors were because we think that the Cnidarians have adapted to them.
Absorption is greatest for the long wavelengths (e.g. red [8]) and, therefore,
shorter wavelengths (e.g. blue) penetrate deeper into the seawater column and
increase in relative proportion with depth (NCBI, 2014). Thus, corals usually
receive blue light, and rarely receive colors that are in the red spectrum.
Therefore, since the colors red and blue are the extremes, Cnidarians would have
adapted the most and least respectively to them.
In a nutshell, these colors are chosen
as they are the extreme ends of the spectrum of colors, which affects the two
factors, and should ensure a more conclusive result.
Method / Testing and Redesign
4a. Main Materials
Symbiodinium (dinoflagellate algae)
Aiptasia pulchella (sea anemone)
Red Light
Blue Light
Sea Water
4b. Variables
Independent Variable: Colour of light
Dependent Variable: Population of
symbiodinium
Constant Variables:
Type of water
Time of incubation
Intensity of light
Type of sea anemone
Type of symbiodinium
Temperature of water
4c. How we ensured it was fair
We counted the results multiple times to
ensure that it is accurate
We used 5 data sets to ensure its
reliability and accuracy
We used the same magnification of the
microscope same for all the 5 data sets
We kept the samples in a pitch dark room
to ensure that there is only red and blue light present to affect the results.
4d. Safety measures
1. We did not enter or work in
laboratories unless a teacher/professor is present.
2. We did not eat, drink or play in
laboratories.
3. We authorized all experiments by
asking our teachers and professors.
4. We kept workbench clean and tidy at
all times. At the end of each practical lesson, we cleared up, wiped and dried
the workbench before leaving the laboratory. So as to prevent any leftover
chemical that might have dropped on the workbench from possibly harming the
next user of the laboratory.
5. We washed our hands thoroughly with
soap before leaving the
laboratory.
6. We did not take any apparatus or
chemicals out of the laboratory.
7. We never touched chemicals with their
bare hands we used a
dropper to transfer liquids.
8. We never consumed any potentially
dangerous chemicals.
9. We did not tamper with electrical
mains and other things in the laboratory.
4e. Procedure
1. Let the algae clade be cultured for
11 hours under light irradiation
2. Harvest the algae samples and prepare
them for the actual experiment
3. Wash the Sea Anemone with Fresh Sea
Water twice
4. Incubate the Sea Anemone with the
Algae for 1 hour
5.Wash the Sea Anemone again with Fresh
Sea Water twice
6. Place one sample under blue light and
another under red light
7. Wait for 72 hours to see the results
8. After 72 hours, gently place the Sea
Anemone on a glass slide and view it under a microscope at 40x
9. Count the number of algae present in
the Sea Anemone
10. We later calculated the standard
deviation of the ratio of the number of algae cell in the red light and blue
light. Using this formula,
Where {x1, x2,.... xn}are the observed values
of the sample items, x is the mean value of these observations, and N is the number of observations in the sample (Wikipedia, 2018c).
Results
We collected 5 sets of samples from 5
groups of people who did the experiment and analyzed the 5 sets of samples of
sea anemone under a microscope. We counted the number of algae cells that were
evidently visible. The data we have collected is presented below.
The average ratio of the number of algae
cell in blue to a red light is 10.29:1. The standard deviation is approximately 5
this we can conclude that blue light causes more algae cell to be present in
the sea anemone tentacles than the red light.
Expressed in 1 s.f., the average ratio
with its associated error is 10+5 to 1. The photos we took are in the attached
media.
Note: The algae are those greenish blobs and not the black dots.
Conclusion
This experiment results positively supports
our hypothesis as the average amount of algae present in sea anemone exposed
under blue light is more than 10 times more than the ones exposed under red
light -- which is a very significant difference. This also proves that
Cnidarians exposed under blue light would grow beer than that under red light.
However, the standard deviation of the
ratio is +5, which is quite a significant error. This could be due to several
limitations in our experiment. For example, we only had limited samples and
time. Furthermore, although the ratio was similar throughout, the number of
algae in some algae samples were significantly different. This could be due to
different amounts of pressure exerted on the glass slide when placing the
sample under the slide. The light that was cast over the set-up may be further
away from the other setups. This may be another reason the number of algae in
some algae samples was significantly different.
In the future, we could consider having
more samples and increasing the incubation period. As for the counting of the
algae, we could use the fine adjustment knob view different layers of the
specimen where algae might be found in. Once the specimen is close to in focus,
the fine-adjustment knob can be used to sharpen the image or focus on different
layers in the specimen (David M., 2015).
This knowledge has led us to the
creation of our engineering research. Sunlight usually cannot penetrate water
deep enough for corals and sea anemone to grow well beyond the euphotic zone.
In order to promote the growth of Cnidarians, we have designed a photovoltaic
blue light delivery system to the Cnidarians on the seabed. This solution will
increase the growth rate of Cnidarians that will help promote a healthier coral
reef ecosystem and improve the life underwater, which is one of the UN Global
Goals.
About me
I am Prasanna. I have created my own
circuits using Arduino. This got me interested in STEM, which influenced me to
be an engineer who can solve serious problems like the scientist whom I admire,
Nikola Tesla. He has inspired me not only to think out of the box like the
Wardenclyffe Tower but also to constantly improve the current findings. Winning
to me is gaining new experience and persevering through. I would consider
anything a victory if I have done my best.
Hello! I’m Shi Yu. I love to study, as I
acquire a sense of accomplishment that motivates me. I got interested in STEM
as I aspire to be a scientist; to become like my idol, Stephen Hawkings. In my
opinion, he has earned his dignity through his positive attitude towards the
challenges he faced. Admirable, I’d say. This competition is a learning
experience for me as I feel, that is what counts. Thus, victorious or not, I
hope that I have learned something.
I am Naythan, a 13-year-old who is
passionate about research. A coral camp that I’ve attended got me interested in
my area of STEM, science. This influenced me to conduct more Science
Research about other topics. Thomas Edison was the scientist that inspired me
to never give up. Though we faced many challenges, perseverance was key to our
success. That to me is winning.
Health & Safety
1. We did not enter or work in
laboratories unless a teacher/professor is present.
2. We did not eat, drink or play in
laboratories.
3. We authorized all experiments by
asking our teachers and professors.
4. We kept workbench clean and tidy at
all times. At the end of each practical lesson, we cleared up, wiped and dried
the workbench before leaving the laboratory. So as to prevent any leftover chemicals that might have dropped on the workbench from possibly harming the next user of
the laboratory.
5. We washed our hands thoroughly with
soap before leaving the
laboratory.
6. We did not take any apparatus or
chemicals out of the laboratory.
7. We never touched chemicals with their
bare hands we used a dropper to transfer liquids.
8. We never consumed any potentially
dangerous chemicals.
9. We did not tamper with electrical
mains and other things in the laboratory.
Bibliography, references, and acknowledgments
National Center for Biotechnology
Information (NCBI). (2014). Red Light Represses the Photophysiology of the
Scleractinian Coral Stylophora pistillata. Retrieved December 5, 2018, from
hps://www.ncbi.nlm.nih.gov/pmc/aicles/PMC3962463/
Wikipedia (2018a). Sea anemone.
Retrieved November 28, 2018, from https://en.wikipedia.org/wiki/Sea_anemone
Wikipedia (2018b). Color. Retrieved
November 28, 2018, from https://en.wikipedia.org/wiki/Color
Freudenrich, P. C. (2000). How Light
Works. Retrieved November 28, 2018, from
https://science.howstuworks.com/light.htm
David, M. (2015). What does the
coarse-adjustment knob on a microscope do? Retrieved December 6, 2018, from
hps://www.quora.com/What-does-the-coarse-adjustment-knob-on-a-microscope-do
Truong-Son N. (2015). What color light
has the highest frequency? Retrieved December 10, 2018, from
https://socratic.org/questions/5348556b02bf347bed8fed
National Aeronautics and Space
Administration (NASA). (2018). Multiwavelength Milky Way: Electromagnetic
Spectrum. Retrieved December 10, 2018, from https://asd.gsfc.nasa.gov/archive/mwmw/mmw_rainbow.html
University of California, Santa Barbara
(UCSB) Science Line. (2014). How does the level of light affect the rate of
photosynthesis? Retrieved December 10, 2018, from
https://scienceline.ucsb.edu/getkey.php? key=4647
Wikipedia (2018c). Standard Deviation.
Retrieved December 11, 2018, from https://en.wikipedia.org/wiki/Standard_deviation
We would like to thank Mr. Tan Hoe Teck,
our science teacher who provided us with constructive comments about our
project. He also provided many suggestions on how we could improve our project
to get accurate and reliable results.
We would like to thank National Dong Hwa
University, Taiwan for providing great hospitality to conduct research and
experiments.
We would also like to thank Professor Li
Hsueh Wang who gave us a more detailed background into coral growth and its
symbiodinium. Furthermore, we would like to extend our thanks to the
researchers (Hung- Kai Chen and Vincent) who assisted in using the microscope.
Finally, we would like to thank the different
groups who supported us with data for the experiment:
Group A: Ng Shi Yu, Yeo Zhen Xi Naythan,
Thangaraja Prasanna, Seow Kit Hint, Muhammad Adam Aqasha Bin Mohamed Hisham
Group B: Reuben Ng, Teo Yao Hong, Norman
Hamdan, Kai Chong, Zachary Kegan Sim Yanxi
Group C: Kannan Vignesh Raj, Mikail
Faris Akbar, Linus Chee Wee Rung, Zhang Xu Cheng, Tan Song Ze
Group D: Saw Yadira, Woo Syn Ting Sara,
Tang Ning Chloe Nicholle, Andrien Zheng Kai Jie, Kuan Chen Yang Nathaniel
Group E: Kuan Kwok Yong, Khoo Seok Ying,
Lun Su Yen
So once again, we will like to thank all these people who helped to
make this project possible.
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