The relationship between the frequency of visible light transferred and its effects on the growth of algae.
Introduction I was curious about the works of a Dr. John Ott on the effects of various colors of light and its on the growth and development of organisms. I decided to investigate how do different wavelengths of light influence the growth of algae. Focusing on the growth of algae was a choice to do with the research that is being done with algal biofuels which may lessen our dependence on fossil fuels. Searching for the optimal conditions for algal growth is the main ideas behind this experiment. My hypothesis was that algae in the test tubes with the filters of the longest frequencies …show more content…
After two weeks stir the test tubes and add the solution from each test tube to a cuvette to fill it ¾ of the way.
8. Make sure that the algae are evenly displaced before sliding the cuvette into the slot on the spectrophotometer.
9. Use a spectrophotometer to determine the density of the algae in the water by testing the light absorption in the solution.
Results
Observations
Day 1- The algae solution was added to all test tubes. The algae cells are green in color.
Day 3- The algae appear to have settled on the bottom of the test tubes. The solution above appears generally clear.
Day 6- The amount of algae does not appear to be increasing in either of the test tubes.
Day 10- The solution of water above the algae that has long settled on the bottom is becoming foggier and the algae is becoming yellowish.
Day 12- The algae that are settled at the bottoms of the beakers appears to be losing color. It is of a faint color. The algae may be lacking nutrients necessary to keep them alive.
The following picture (Figure 1) is of the cuvettes filled with the samples of the algae solution after 14 days:
a. No light
b. Red filter
c. Yellow filter
d. Green filter
e. Blue …show more content…
The point of using a spectrophotometer was to look at the density of the algal growth. To make my measurements I added a sample of the solution from each test tube to a cuvette and then placed the cuvette in the spectrophotometer. The solution contained in the cuvettes was largely water with an amount of algae cells which consistently settled on the bottom of the cuvette if it was untouched for a while. This may have affected the readings of the spectrophotometer considering that the cuvette became clearer over time as the solid contents precipitated. Next time I could make sure that I have sufficient amounts of algae to fill each cuvette, so to say, the initial amount of algae added to the test tubes would have to be greater and they would have to be “fed” to allow