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

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

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

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

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

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

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

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

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

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

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

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^-13. Day 14=1.87 * 10^-16 Results Dunnett’s Test T-crit= 3.29 Sig. Variation for all Samples

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

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

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

References Algae Research and Supply. “Lighting for Algae Cultures.” Retrieved from:https://algaeresearchsupply.com/pages/lighting-for-algae- cultures Neubert, David. (2017 July 26). “Seeing Things in a Different Light.” Retrieved from:https://www.batteriesplus.com/blog/lighting/seeing-things- in-a-different-light Mooij, Tim. (April 2016). “Impact of Light Color on Photobioreactor Productivity.” Retrievd from: ttps://www.sciencedirect.com/science/article/pii/S221192641630 0261

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

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

Day 2 - Anova: Single Factor SUMMARY Groups Count Sum Average Variance White 5 1.02 0.204 0.00013 Blue 0.91 0.182 0.00007 Red 0.78 0.156 Green 0.76 0.152 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 0.008855 3 0.002951667 29.51666667 9.33571E-07 3.238871517 Within Groups 0.0016 16 0.0001 Total 0.010455 19  

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

Day 4 - Anova: Single Factor SUMMARY Groups Count Sum Average Variance White 5 1.23 0.246 0.00018 Blue 1.37 0.274 0.00013 Red 1.08 0.216 0.00028 Green 0.8 0.16 0.00015 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 0.03572 3 0.011906667 64.36036036 3.79043E-09 3.238871517 Within Groups 0.00296 16 0.000185 Total 0.03868 19  

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

Day 8 - Anova: Single Factor SUMMARY Groups Count Sum Average Variance White 5 1.69 0.338 0.00052 Blue 1.97 0.394 0.00033 Red 1.56 0.312 0.00027 Green 0.65 0.13 0.00015 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 0.195775 3 0.065258333 205.5380577 5.5266E-13 3.238871517 Within Groups 0.00508 16 0.0003175 Total 0.200855 19  

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

Day 14 - Anova: Single Factor SUMMARY Groups Count Sum Average Variance White 5 2.39 0.478 0.00022 Blue 2.66 0.532 0.00037 Red 2.17 0.434 0.00068 Green 0.39 0.078 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 0.634135 3 0.211378333 567.458613 1.87827E-16 3.238871517 Within Groups 0.00596 16 0.0003725 Total 0.640095 19  

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

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 3 536.1333333 121.1600753 3.27113E-11 3.238871517 Within Groups 70.8 16 4.425 Total 1679.2 19  

‘T’ Test (Hemocytometer)