|
|
|
Researched by Cody J.
|
|
The purpose of this experiment was to determine the effect of pollution on daphnia.
I became interested in this idea when I received my brine shrimp, which I raise at home. Also, I have been interested in small aquatic life ever since going on an oceanographic field trip in 5th grade.
The information gained from this experiment will help inform the public how pollution in the water, affects marine life. It will also inform fishermen about how pollution will affect the food chain. Pollution might affect how many fish are in the ocean, and where to fish.
My hypothesis is that the higher the pollution concentration the lower the percentage of surviving daphnia. The low level of pollution will affect the daphnia slightly.
I base my hypothesis on the following quote from Microsoft Encarta 2000 "The acid rain can be carried into a stream or lake, becoming a form of water pollution that can harm or even eliminate wildlife."
The constants in this study
were:
* Petri dishes used
* Water source
* Daphnia
* Testing procedure
The manipulated variable was the amount of pollution in each jar.
The responding variable was how many adult daphnia live and grow.
To measure the responding variable, I will look at their heart to see if they have a pulse. I will view them with a magnified eyepiece.
| QUANTITY | ITEM DESCRIPTION |
| 13 | Petri Dishes |
| 1 | Magnified Eyepiece |
| 250 ml | Ammonia |
| 250 ml | Hydrochloric Acid pH=2.0 |
| 250 ml | Detergent |
| 4 | one liter containers |
| 1 | eyedropper |
1. Get three clean milk
jugs that each have 2,250 ml of regular tap water.
2. Label one acid, another
ammonia, and the last one detergent.
3. Take the acid jug and
add 250 ml of pH 2.0 hydrochloric acid to the 750 ml of tap water.
4. Take out 5 ml of solution
out of the acid mixture and pour it into on petri dish, label it 10%
5. Take 750 ml of solution
out of the original jug and put it in a different jug. Add 250 ml of fresh
water to the mixture.
6. Pour out 5 ml and pour
it into a petri dish, label it 7.5%
7. Take out 500 ml of original
solution and add 500 ml of tap water to the 500 ml of acid. Take out 5
ml and add it to a petri dish and label it 5%
8. Pour 250 ml of original
solution out and add 750 ml of tap water to it. Take out 5 ml of the solution
and add it to a petri dish, label it 2.5%
9. Make sure to dump out
all excess solution before doing the next steps.
10. Repeat steps 2-9, except
use the ammonia and detergents instead of the acid.
11. Now put five daphnia
into each container.
12. Wait two hours and using
the eyepiece to see the daphnia’s pulse, record how many survived the experiment
in each different solution.
The original purpose of this experiment was to determine the effect of pollution on daphnia.
The results of the experiment
were, that as the concentration of pollution got higher the daphnia slowed
down and eventually died. They showed no resistance to the ammonia and
died instantly.
My hypothesis was that the higher the pollution mixture, the lower the percentage of surviving daphnia. The low level of pollution will affect the daphnia slightly.
The results indicate that this hypothesis should be accepted, because as the concentration of pollution got higher the daphnia died. It was very strange that even the 2.5% concentration of ammonia still killed the daphnia immediately.
Because of the results of this experiment, I wonder if that the daphnia would show a little resistance if I would have mixed the ammonia solution down to a lower concentration.
If I were to conduct this project again I would have diluted the ammonia down to a smaller concentration so I would have data to show for the ammonia part of my research.
Menu of 1999-2000 Science Projects