To determine whether water that contains a measurable level of acid—with a pH level below 7 (to simulate acid rain)—will affect the cellular structure of Spirogyra, a common freshwater algae of the phylum Chlorophyta.
- 3 Spirogyra algae cultures
- 3 1-gallon (3.79-liter) fishbowls
- 6 quarts Oiters) distilled water
- 1 quart Oiter) soil/water mixture (5 mg soil and 1 quart Oiter) tap water)
- 3 lamps, each with 40-watt bulb
- dropper (cc-calibrated)
- concave microscope slides
- 200x microscope
- pH indicator
- 15 cc of 90% water and 10% sulfuric acid
Cultures of Spirogyra will be grown in three separate fishbowls. One will contain healthy algae cultivated in pollution-free water. Another will contain healthy algae cultivated in a low-acid water solution (water in which a small amount of acid solution is added to bring the pH to a level of 6.0). The third fishbowl will contain healthy algae cultivated in a high-acid water solution (water in which a greater amount of acid solution is added to bring the pH to a level of 3.0). Specimens from each tank will be drawn daily and observed with a 200x microscope. These observations will be recorded and labeled.
- Place equal amounts of Spirogyra cultures separately in the three fishbowls which should contain 2 quarts Oiters) of distilled water. Then, add an equal amount of the soil/water mixture to each bowl to promote rapid algae growth. Place each bowl under a 40-watt lamp and heat to 68 degrees Fahrenheit (20 degrees Celsius).
- Observe and record the algae growth daily.
- When the algae appear healthy and abundant, take a sample from each tank and observe it on slides under the microscope. Be sure to label the samples as to the specific bowl from which they were taken.
- Allow the algae to grow under optimum laboratory conditions for ten days. On the tenth day, take another sample from each of the three bowls and observe them on slides under the microscope. Measure the pH level of the water, using the pH indicator. A neutral solution should be found in each bowl.
- Acid Rain Day 1: The simulated acid rain will now be administered to the bowls. (Bowl 1 will be left with the neutral solution of water and healthy algae to serve as the control.) With the dropper, add 3 cc of the mixture of water and 10% sulfuric acid (to yield a pH of 6.0) into Bowl 2. Into Bowl 3, add 12 cc of the mixture of water and 10% sulfuric acid (to yield a pH of 3.0). Immediately take an algae sample from these two bowls for microscopic viewing, and draw and label the results.
- Acid Rain Day 2: 24 hours after the simulated acid rain has entered the water supply of the Spirogyra, take samples of the algae again from each bowl (including the control) and observe them under the microscope. Note any changes in the algae cell structure. Draw and label what you see.
- Acid Rain Day 3: 48 hours after the simulated acid rain has entered the water supply of the Spirogyra, take algae samples from each bowl (including the control) and observe them under the microscope. Note any increased cellular changes. Again, draw and label what you see.
- Compare the differences in the cell structures between the three sanlples for the 3-day period.
- Locate a diagram of a typical, healthy Spirogyra cell. Is this diagram consistent with your final drawing of algae from Bow11? Compare this diagram with your final drawings from Bowls 2 and 3. Were there any changes at all in the structure of the algae? If so, what part of the algae's cellular structure has been altered?
- What conclusions can be drawn from the effects that the simulated acid rain had on the Spirogyra? Was this simulation comparable to actual acid rain? What other acids might be used to simulate the rain?