1. Wavelength Influence on Algal Growth
By: Aidan Madjerich
Grade 9
Central Catholic High School
PJAS 2019

2. Question
How do different wavelengths of light affect Chlamydomonas reinhardtii population growth?

3. Light Spectrum
Most plants and algae absorb and/or deflect varying wavelengths of light.
Blue, White, Green, and Red lights were used

4. Photosynthesis
Light energy is used to synthesize carbohydrates and/or other rich molecules
In Eukaryotic photosynthetic cells, chloroplasts serve as the photosynthetic organelle.

5. Chlamydomonas reinhardtii
An autotrophic, single celled flagellate
Both freshwater and saltwater are fundamental habitats
Reproduction is mainly asexual, but sexual fusion can occur
Tolerant of wide range of light intensities
Used in many models, such as phototaxis, due to simplicity and clarity in function

6. Phototaxis An eyespot detects the surrounding environment for light
Intensity of light on the eyespot acts as a signal
Cell body develops a cyclic movement between light and no light
Can move away or towards light

7. Purpose
To determine the effects of different wavelengths of light on Chlamydomonas reinhardtii population growth

8. Hypotheses
Null: The wavelengths will not vary significantly in their effect on Chlamydomonas reinhardtii population growth
Alternative: The colored lights will significantly vary in their effect on the population growth of Chlamydomonas reinhardtii

9. Materials Chlamydomonas Reinhardtii (Carolina Science) Soil Water
Spring Water
One (1) red flood light emitting bulb, 13.5 Watt
One (1) blue flood light emitting bulb, 13.5 Watt
One (1) white flood light emitting bulb, 12.0 Watt
One (1) green flood light emitting bulb, 13.5 Watt
(21) borosilicate culture test tubes (13 X 100mm)
One (1) Spectrometer
One (1) Hemocytometer
One (1) Macropipette
One (1) Micropipette

10. Procedure
15mLs of algae, 12mLs of spring water, and 3mLs of soil water were pipetted into each of the five (5) 50 mL conical tubes
Once the solution was fully mixed and set out for about a day, 5mL of the solution was pipetted into (20) culture tubes
Five (5) culture tubes were placed in a tube rack and each one of these rack were directly placed under each light (approximately 1.0 meter from the bulb)
Each rack was exposed to (16) hours of light and (8) hours of no light each day
Absorbance readings were taken at 430nm every two (2) days

11. Procedure (continued)
The racks were placed with the culture tubes under each correct light fixture
Previous two (2) steps were repeated seven (7) times total
On day ten (10), cell counts were performed using a hemocytometer

12. Results P value: Dunnett’s Test T-crit= 3.29 Sig. Variation for all
P values: Day 2=9.33 * 10^-7. Day 4=3.79 * 10^-9. Day 8=5.52 * 10^ Day 14=1.87 * 10^-16
Results
Dunnett’s Test
T-crit= 3.29
Sig. Variation for all
Samples

13. Hemocytometer (Day 10) DAY 10 Sig Variation Dunnett’s Test
T-crit= 3.29
Control
Sig Variation
Sig Variation
P-value: 3.27 * 10^-11

14. Conclusion The Null Hypothesis can be rejected for days 2-14.
The order of growth stimulation: Blue, White, Red, Green
The t-tests show that each experimental group varied significantly when compared to the control (White) for days 2-14.
Order of greatest cell/mL concentration: Blue, White, Red, Green
Null can be denied for the Hemocytometer results
The t-test showed variation for all 3 experimental groups

15. Limitations And Extensions
Possible intruding light on the tested algae.
Unknown power of light effect on the tested sample
Unknown initial health of Algal samples
Extensions
Use the same bulbs with the same wattage and power
Use a photometer to determine the exact exposure
Optimal schedule of lighting on the algae

16. References
Algae Research and Supply. “Lighting for Algae Cultures.” Retrieved from: cultures
Neubert, David. (2017 July 26). “Seeing Things in a Different Light.” Retrieved from: in-a-different-light
Mooij, Tim. (April 2016). “Impact of Light Color on Photobioreactor Productivity.” Retrievd from: ttps:// 0261

17. Hemocytometer
A Hemocytometer is a scientific instrument used to count the amount of viable and/or unviable cells in a certain unit.
It is a rectangular slide that contains a laser-etched grid in the middle of two (2) chambers
Originally used to count red blood cells, it is now been adapted to encompass a wide variety of microbes

18. Spectrophotometer
A Spectrometer is another type of scientific instrument specifically designed to examine a spectrum of variables
The set wavelength on the spectrometer is usually 430nm because that is the measurement of Chlorophyll A’s performance and/or ability to absorb light

19. Day 2 - Anova: Single Factor
SUMMARY
Groups
Count
Sum
Average
Variance
White 5
1.02
0.204
Blue
0.91
0.182
Red
0.78
0.156
Green
0.76
0.152
ANOVA
Source of Variation SS df MS F
P-value
F crit
Between Groups 3
E-07
Within Groups
0.0016 16
0.0001
Total 19

20. Day 2 – ‘T’ Test T Value T Critical Blue 3.42 3.29 Variation Green
T Value
T Critical
Blue
3.42
3.29
Variation
Green
8.22
Red
7.58

21. Day 4 - Anova: Single Factor
SUMMARY
Groups
Count
Sum
Average
Variance
White 5
1.23
0.246
Blue
1.37
0.274
Red
1.08
0.216
Green
0.8
0.16
ANOVA
Source of Variation SS df MS F
P-value
F crit
Between Groups 3
E-09
Within Groups 16
Total 19

22. Day 4 – ‘T’ Test T Value T Critical Blue 4.42 3.29 Variation Green
T Value
T Critical
Blue
4.42
3.29
Variation
Green
13.59
Red
4.74

23. Day 8 - Anova: Single Factor
SUMMARY
Groups
Count
Sum
Average
Variance
White 5
1.69
0.338
Blue
1.97
0.394
Red
1.56
0.312
Green
0.65
0.13
ANOVA
Source of Variation SS df MS F
P-value
F crit
Between Groups 3
5.5266E-13
Within Groups 16
Total 19

24. Day 8 – ‘T’ Test T Value T Critical Blue 8.75 3.29 Variation Green
T Value
T Critical
Blue
8.75
3.29
Variation
Green
32.88
Red
4.11

25. Day 14 - Anova: Single Factor
SUMMARY
Groups
Count
Sum
Average
Variance
White 5
2.39
0.478
Blue
2.66
0.532
Red
2.17
0.434
Green
0.39
0.078
ANOVA
Source of Variation SS df MS F
P-value
F crit
Between Groups 3
E-16
Within Groups 16
Total 19

26. Day 14 – ‘T’ Test T Value T Critical Blue 8.53 3.29 Variation Green
T Value
T Critical
Blue
8.53
3.29
Variation
Green
63.24
Red
6.95

27. Anova (Hemocytometer Results)
Anova: Single Factor
SUMMARY
Groups
Count
Sum
Average
Variance
Blue 5
216
43.2
6.2
White
171
34.2
2.7
Red
145 29
4.5
Green 92
18.4
4.3
ANOVA
Source of Variation SS df MS F
P-value
F crit
Between Groups
1608.4 3
E-11
Within Groups
70.8 16
4.425
Total
1679.2 19

28. ‘T’ Test (Hemocytometer)