This is the project Andrea and I designed and carried out for our IB Biology 11 class. I got 100%!

Background Information: Many aquatic environments have affected by acidic rain as a result of factory and vehicle emissions of SO2, a chemical which reacts with water in the atmosphere to form sulfuric acid. The sulfuric acid falls to the earth as acid rain, and damages the environment. In this experiment, we were curious to see if algae would have a reversing effect on the aquatic organisms, and help them to retain their health in a more acidic and toxic environment. However, because algae would have quickly died at a low pH level, the pH level of acidic water used was not that low; therefore, the slightly acidic water would not kill the algae before the health of the organisms could be tested.

Problem/Research Question: Does algae that is placed in simulated acid rain (with a minimal acidic pH level), allow brine shrimp to maintain fitness for a longer period of time than if placed in water affected by acid rain (of the same minimal acidic pH level), with no algae present?

Hypothesis: The brine shrimp, placed in the water not affected by acid rain but containing algae, will be able to maintain their fitness. The brine shrimp's flap rate will not change significantly because of the more natural environment of algae and non-toxic water. When brine shrimp are placed in water containing algae affected by acid rain, the flap rates will probably decrease because of the unhealthy water and possible lack of oxygen. In the test in which the water is affected by acid rain with no algae, the brine shrimp will have the lowest flap rate because of the toxins, and lack of algae, which may provide essential oxygen in toxic environments.

Selection of Variables: Petri dish #1:
-Spring water (pH between 7-8)
-Algae (equal amount in #2)

Petri dish #2:
-Acidic spring water (pH between 5-6)
-Algae (equal amount in #1)

Petri Dish #3:
-Acidic spring water (pH between 5-6, same water as #2)
-No algae

Apparatus/Materials:
Solutions:
-Spring water
-sulfuric acid ( H2SO4) 3 M diluted to 0.008 M
-pH paper
-Baking soda
-Graduated cylinders
-Glass stir stick
-2-400 mL beakers

Testing Equipment:
-3 Petri dishes
-Eye droppers
-Microscope
-Depression slides

Organisms:
-Brine shrimp
-Volvox (unicellular algae)

Method:

Preparing the Solutions:

1. For the normal water, spring water with a pH level of 6 was used. In a beaker, 3 mL of dry baking soda was added gradually to 325 mL of water to change the pH to between 7-8.
2. For the acidic water, the same spring water was used as in step #1. The pH level was lowered by adding 118 mL of 0.008 M sulfuric acid (H2SO4 ), and a pH level of 5-6 was reached in the water.
3. The solutions were stored in containers so they could be easily accessed for the tests.

Petri Dish #1: Natural Water and Algae

1. Placed 20 mL of spring water, pH level 7-8, into a Petri dish 1.
2. Added 2 mL of algae to solution, and stirred it to ensure it was uniformly distributed.
3. Allowed algae and water to be exposed to fluorescent lights for three hours to allow for chemical change.
4. Placed a Brine shrimp in the solution.
5. After a 5-minute exposure, the brine shrimp was quickly removed with an eyedropper, and placed on a slide under a microscope. Its flap rate was calculated by counting for 15 seconds, multiplying by 4, and the results (in flaps per minute) were recorded in table 1. 6. Placed the Brine shrimp back in Petri dish 1.
7. After 5 more minutes (10-min exposure), step 5 and 6 were repeated.
8. After another 5 minutes (15-min exposure), steps 5 and 6 were repeated.

Petri Dish #2: Acidic Water and Algae
1. Placed 20 mL of acid water solution, pH level 5-6, into a Petri dish 2.
2. Added 2 mL of algae to Petri dish and stirred to ensure it was uniformly distributed.
3. Allowed algae and water to be exposed to fluorescent lights for three hours to allow for chemical change.
4. Placed a brine shrimp in the solution.
5. After a 5-minute exposure, the brine shrimp was quickly removed with an eyedropper, and placed on a slide under a microscope. Its flap rate was calculated by counting for 15 seconds, multiplying by 4, and the results (in flaps per minute) were recorded in table 2.
6. Placed the brine shrimp back in Petri dish 2.
7. After 5 more minutes (10-min exposure), step 5 and 6 were repeated.
8. After another 5 minutes (15-min exposure), steps 5 and 6 were repeated.

Petri Dish #3: Acidic Water and No Algae
1. Placed 20 mL of acidic water solution, pH level 5-6, into Petri dish 3.
2. Added 2 mL of spring water (to account for missing volume of algae for means of control over variables).
3. Placed a brine shrimp in the solution.
4. After a 5-minute exposure, the brine shrimp was quickly removed with an eyedropper, and placed on a slide under a microscope. Its flap rate was calculated by counting flaps for 15 seconds, multiplying by 4. The results (in flaps per minute) were recorded in table 3.
5. Placed the brine shrimp back in Petri dish 3.
6. After 5 more minutes (10-min exposure), step 4 and 5 were repeated.
7. After another 5 minutes (15-min exposure), steps 4 and 5 were repeated.

Data Collection It's just a bunch of charts and numbers...

Data Analysis: Overall Average Flaps per minute for Each Test

#1: Spring Water With Algae
152
#2: Acidic Water with Algae
154
#3: Acidic Water with no Algae
143
Evaluation

Evaluation of Results:

The hypothesis that brine shrimp exposed to acidic water with algae would have a higher flap rate than brine shrimp exposed to acidic water with no algae, is supported in the results (see table 4 and chart 1). Within each test, as the shrimp are exposed for a longer period of time, the average flap rate also decreases. The general trend appears to be that the alkaline spring water allows for the best retention of fitness and health, followed by acidic water with algae, and then acidic water lacking algae being the least healthiest. In test #1 for a ten-minute exposure, this trend is not apparent because of the large drop to 129 flaps/minute as an average. In data collection, table 1, for brine shrimp one and two in the 10-minute exposure, there is two very low rates of 96 flaps/min and 100 flaps/min. These may have been inaccurate due to the tester's inexperience with counting flaps (these were some of the first tests to be carried out). If these flap rates had been counted more accurately, the trend supporting the hypothesis may have remained the same for all the averages. The overall averages show that that the acidic water with algae has the highest average of 154 flaps per minute, while the average for the alkaline spring water with algae is 152. The differences in the flap rates are not large though, and again, there may be an error due to miscount in the first few tests. However, until more tests are carried out, it will not be known whether the results are really valid or simply coincidence because of the errors and limitations of this experiment.

Evaluation of Procedure

There were some limitations and errors in the procedures for this experiment. When preparing the acidic and alkaline solutions, the pH paper was no very accurate and our estimate of the error was +/- 0.5 pH. The pH level of the acidic water may have been at a level of pH 6, rather than the desired pH of 5.0. The acidic pH level had to be minimally acidic because the algae may have died at an low level such as 3 or 4. Also, the alkaline water may have been neutral (pH 7) rather than closer to pH 8. The algae used must also be accounted for as a limitation. The algae used was Volvox which is unicellular, and is therefore, difficult to accurately measure. The assumption made in this experiment was that if the algae was stirred in its original container, it would be uniformly distributed. So, when a certain volume was taken, it was assumed that approximately the same amount of algae would be present every time that volume was extracted from the container. Also, there was a limited amount of algae, so there may not have been enough of it to have any significant effect on the brine shrimp. The use of Brine shrimp was also had errors. Brine shrimp are salt-water organisms, so they may have reacted differently to the experiment than fresh water organisms would have reacted. Also, the brine shrimp flap rates were very inaccurate because of the fast and sometimes irregular speed at which they flapped. The brine shrimp varied in size, age, and probably health, so this may have affected our results as well. One error in particular was when a brine shrimp slightly too large was used; most of the brine shrimp were approximately the same size, but some were large enough to become slightly stuck on the glass slide, so some flap rates may have been lower as a result.

Modifying the Procedure

Several modifications to this experiment can be made to improve it and make the results more accurate. First, in order to determine a more accurate and exact pH level for the solutions, a pH counter (digital pH monitor) could be used to replace the pH paper. Second, the algae used should be multicellular so it can be seen to be measured accurately and used in greater quantities. Alternatively, in place of algae, water plants could be used as well. Third, a more ideal organism to use for the experiment is Daphnia because under a microscope, the Daphnia heart can easily be viewed, and its heart rate can be calculated. The heart rate of an organism will reflect the response to an altered environment more accurately than flaps because heart rate is involuntary and regular. Another alternative modification is to expose the brine shrimp, algae, and water together to a light for 3 hours and then testing the flap rates, rather than placing the brine shrimp in after the water has been exposed to light for 3 hours without it. Doing this may produce results with more difference between them because the organism would have time to actually live in the environment, which would have a greater affect on their bodies than a 15-minute exposure.

[SARCASM]no brine shrimp died for this momentous and groundbreaking cause that will solve all of the world's problems in a nutshell [/SARCASM]