The Effect of Light Wave Length on Algae Growth Clay Wyda Grade 9 Pittsburgh Central Catholic

Light Spectrum Visible light has moderate wavelength and energy. Life has adapted to make use of or resist this radiation Explain the visible light spectrum

Photosynthesis Photosynthesis takes place in organelles called chloroplasts. light-dependent reactions occur in the thylakoid membranes of the chloroplasts and use light energy to synthesize ATP and NADPH. Euglena utilizes chloroplasts, containing Chlorophyll a, Chlorophyll b, and some carotenoid pigments

Photosynthesis chlorophyll is much more efficient at using the red and blue spectrums of light to carry out photosynthesis.

Euglena Common algal like protist Extremely tolerant of many habitats Capable of survival in both salt and water environments Uses a flagella for movement in its environment A partial heterotroph- can attain food through endocytosis and photosynthesis

Purpose To determine which spectrum of light euglena algae grows best in.

Hypothesis Null- algae growth will not vary significantly when exposed to varying colors (wavelengths) of light. Alternate – Algal growth will vary significantly when exposed to different light colors.

Materials Fifty 13 x 100 borosilicate culture test tubes 50 ml of Euglena gracilis algae Pipettes and a Pipette pump 5 60watt light bulbs 4 light screens(red, blue, green, yellow) 5 test tube racks (that do not cover the sides of the test tubes) Spectrophotometer (Science Kit Educator) 100 ml of soil water 100 ml of spring water

Procedure Mixed the following ingredients into test tubes: 2ml Spring water 2ml Soil water 1ml Euglena Placed 10 tubes in each rack 10 tubes in the first row The racks were placed approximately 23 cm. away from the edge of the table

Procedure A light bulb was placed at the end of the table 20 cm up It was then angled at 45° toward the Algae The distance from the light to algae was 30 cm A screen was placed over top of the light bulb for 4 of the 5 bulbs (one was without a screen) Next the algae was exposed for 8 hours a day to the lights. Absorbance readings were taken every 3 days with a Spectrophotometer set to the wave length 430 nm for 18 days

Results Anova: Single Factor for Day 22 SUMMARY Groups Count Sum Average Variance Column 1 5 0.658 0.1316 0.000389 Column 2 0.826 0.1652 0.0003 Column 3 0.818 0.1636 0.000224 Column 4 0.754 0.1508 0.000756 Column 5 0.683 0.1366 2.23E-05 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 0.004669 4 0.001167 3.450718 0.026725 2.866081 Within Groups 0.006765 20 0.000338 Total 0.011434 24   The results of the anova show that there was significant variation between the groups. This is because the P-value is less than 0.05

Dunnetts’ test- Day 22 Color T- value T-crit Red 2.327 2.23 Significant Green -0.431 Insignificant Blue 2.491 Yellow 1.224

Conclusion Null – all light will have the same effect – Rejected The hypothesis that algae exposed blue light will grow the best and that the algae exposed to green light will do the worst. – Accepted

Limitations and Extensions Algae was not kept at the same temperature each day Weather variations could have small effects of data Algal cultures might not have been in optimal health Extensions Greater sample sizes. Algal health- the study will be repeated using a fresh culture and a longer period of observation

Sources Campbell, Neil A. and Reece, Jane B. 2008. Biology Eighth Edition. Pearson Benjamin- Cummings. San Francisco, CA Vliet, Kent A. 2008. A Lab Manual for Integrated Principles of Biology Part one- BSC2010L Forth Edition. Pearson Custom. University of Florida.