The Effect of Caffeine on the Survival Rate of Daphnia pulex
Researched by Tiera G. 2000-01	PURPOSE  HYPOTHESIS  EXPERIMENT DESIGN  MATERIALS  PROCEDURES  RESULTS  CONCLUSION  RESEARCH REPORT  BIBLIOGRAPHY  ACKNOWLEDGEMENTS ABOUT THE AUTHOR

The purpose of this experiment was to determine the effect of caffeine on the survival rate of daphnia. 

I became interested in this idea because a lot of soft drinks include caffeine and I was curious what effect caffeine has on people. Daphnia are a good test organism because it is easy to determine whether they are alive or dead.

The information gained from this experiment will help consumers understand the effect of caffeine on themselves and others. Anything that causes the heart to respond unnaturally could be a health concern. 

My hypothesis is that as the amount of caffeine increases the survival rate of the daphnia will decrease. My second hypothesis is that after a certain amount of caffeine is added it will kill the daphnia. 

I base my hypothesis on The World Book Encyclopedia in the article "Caffeine" written by Barbara M. Bayer, "Caffeine is a stimulant," and "When taken in small amounts caffeine increases circulation." 

The constants in this study were:

•  Type of daphnia
•  Temperature the daphnia will be tested
•  Size of container the daphnia will be in
•  Type of water the daphnia will be in
•  Amount of daphnia in each trial
•  Amount of water in each container
•  Amount of time daphnia will sit in caffeinated water
•  Type of caffeine
•  Process of adding caffeine to the daphnia
•  Process of determining whether daphnia are alive or dead

The responding variable was the number of daphnia that lived or died.

To measure the responding variable I used a jeweler’s loupe to watch the visible heart beat on each daphnia and determine whether each is alive or dead.

QUANTITY	ITEM DESCRIPTION
100	Daphnia
1	Caffeine tablet (200 mg)
1	Jewelers’ loupe
1	Eyedropper
5	Divided petri dishes
5	Petri dish covers
5	Experimental cups
1	undivided petri dish
1000	milliliters  Water

1) Gather materials.
2) Label 5 experimental cups "A"-"E." 
3) Let one caffeine tablet (200 mg) dissolve into 500 milliliters of water, this becomes 400 mg of caffeine per 1 liter of water.
4) Stir well and put solution into cup "A."
5) Take 50 ml. of solution out of cup "A," put it into cup "B," and add 200 ml of pure water. This becomes 80 mg of caffeine per 1 l. of water.
6) Take 50 ml. of solution out of cup "B," put it into cup "C," and add 200 ml of pure water. This becomes 18 mg of caffeine per 1 l. of water. 
7) Take 50 ml. of solution out of cup "C," put it in cup "D," and add 200 ml. of pure water. This becomes 3.6 mg. of caffeine per 1 l. of pure water.
8) Take 1 l. of pure water and put it in cup "E."
9) Take divided petri dishes, and put sticky notes with "A" ? "E" and specified amount of caffeine per liter.
10) Take dish "A" and add, using an eyedropper, and add five daphnia to each divided section of the dish. 
11) Add 10 ml. of solution "A" to each divided section of the dish. 
12) Repeat steps 10 and 11 for dishes "B" ? "E."
13) Let the daphnia sit in the caffeine for 17 hours, and check how many daphnia is still alive using the jeweler’s loop.
14) Repeat step 13 in 7 more hours. 

The original purpose of this experiment was to determine the effect of caffeine on the survival rate of daphnia.

The results of the experiment were that the higher concentration of caffeine got the less living daphnia were reported. In 400 mg of caffeine per 1 l. of water, only eight daphnia were reported alive, in 80 mg. of caffeine 12 were reported alive, in 18 mg. of caffeine 12 were reported alive, in 3.6 mg of caffeine 18 were reported alive, and in 0 mg. of caffeine 18 daphnia were reported alive. 
 
 

See the table and graphs.

My hypothesis was that as the amount of caffeine increases the survival rate of the daphnia would decrease. My second hypothesis was that after a certain amount of caffeine is added it will kill the daphnia.

The results indicate that my first hypothesis should be accepted, and the results of my second hypothesis should also be accepted.

Because of the results of this experiment, I wonder about the effect of caffeine on people as well. I wonder if an extremely large amount of caffeine would hurt people like the daphnia. 

My findings should be useful to all caffeine consumers and sellers because they will know the effect of caffeine.  If caffeine does have extremely bad effects (as shown above) the people who consume and sell it in various fashions would want to know this and so would the people who buy any caffeineated substances. 

If I were to conduct this project again I would vary the amounts of caffeine added more than in this experiment. I’d go from an extremely high concentration of caffeine, and go down to no caffeine. I think the results would slightly vary. I would also do each trial more than once; I would do 400 ml. per 1 l. of water two or three times rather than once like I did it. I would also have added more daphnia to each dish.
 
 
 
 

RESEARCH REPORT     INTRODUCTION  There are a lot of people with heart problems. Many factors contribute to this. Whether someone eats too much or exercises too little, there are many people needing help with their heart. Caffeine is considered a stimulant, and in turn increases circulation. It is also found in many substances including chocolate and certain beverages, like coffee, tea, and many soft drinks.  Daphnia are a very important animal in order for fish to survive. They are at the bottom of the food chain, so they are very important. They are used to feed fish, and fish are used for food by many people. If it weren’t for daphnia the population of fish would lower, and some people wouldn’t have their main food resource.  CRUSTACEAN  Crustaceans are animals without a backbone having many legs and a hard external shell. The shells cover the entire body. There are more than 42,00 species of crustaceans. Mainly all crustaceans live in salt water, very few in fresh, and even fewer live on land. They play an extremely large role in water ecology. In most water environments small, floating plants make up phytoplankton, which are foods for some 200 plankton. After this larger crustaceans, fish, or larger sea life eat the crustaceans. Many people eat lobsters, shrimp, crab and other crustaceans. Some crustaceans can destroy wooden ships, docks, and wharves.      DAPHNIA Daphnia are also known as "The Water Flea."  They received their name because of their jerky, swimming motions.  Daphnia are tiny crustaceans that live in lakes and fresh water ponds. They are found in the U.S. and Europe. Daphnia are a major source of food to many water animals, such as eels. Other predators are fish, Hydra, tadpoles, and larva salamanders. Daphnia eat all kinds of small nonfilamentous algae, some types of bacteria, and certain protozoa. They also like to eat Bacillus coli, Euglena, and Chilomonas.  Daphnia are very important because of their large reproduction capacity. They lay every two to three days, and laying at the most, 100 eggs each brood. They can produce two types of eggs. One type is a thin-shelled egg, which is produced in the summer. They also produce thick-shelled eggs, which are produced in the winter. The population of daphnia mainly consists of females. A female may produce as many as twenty-five broods in a their life time, but six is the average. When a female daphnia is four days old she starts reproduction with as many as four to twenty-two eggs. Under less favorable conditions males are produced.  Daphnia are around 0.2 to 18 millimeters long, and have a transparent shell that covers all of the body, excluding the head. The inside of the daphnia can be seen through the shell. They are an oval shape, and have four to six legs, which are used to get food particles out of the water. Their single antenna is used to swim. They have one eye, used for seeing, and there is only one way to determine whether the daphnia is male of female. The males’ intestines are straight, and the females’ are curled.  The nutrients of the daphnia are varied with age and what it eats. The content of protein is usually around fifty percent of the daphnia weight. They are about ninety-five percent water, four percent protein, fifty-four hundredths percent of fat, sixty- seven hundredths percent of carbohydrates, and fifteen hundredths percent of fatty acid. And the acid is vital to survival.  Daphnia are normally fresh water animals, but some are found in slightly salty water. Some have been seen in salinities up to 4 ppt, and salinities of 1.5 to 3.0 ppt are usual in ponds. Oxygen is not as vital to health as fatty acids. Daphnia are normally able to live in poor water quality and dissolved oxygen varies from close to zero to supersaturated. Daphnia dislike fine air bubbles which get trapped inside the shell and force them to float. Daphnia are especially sensitive to metals like copper and zinc. They are also sensitive to pesticides, detergents, bleaches, and other dissolved toxins. This is why well water may be too contaminated and may kill the daphnia. The best kind of water is filtered steam or lake water. The temperatures daphnia can survive are 5-31 degrees Celsius, depending on the type of daphnia.      CAFFEINE Caffeine is found in many substances. It is put in many colas and other soft drinks, and occurs naturally in chocolate and coffee. When it is taken in small amount caffeine is considered a stimulant, and increases circulation. It is also considered harmless for most people. Although when taken in large amounts, caffeine causes nervousness and loss of sleep. It may also cause headaches and digestive disturbances. Caffeine has also been linked to birth defects in lab animals, so for pregnant women it is a advised to be consumed in only small amounts. In studies it has also been able to relieve asthma attacks by clearing the bronchiole tubes.  Caffeine is an odorless, somewhat bitter solid. It is naturally found in leaves, seeds, and fruits of more that 60 plants, although can now be made in laboratories. Caffeine dissolves into water and alcohol.  It also is true that it enhances burning of fat in some people, but mainly it only over stimulates the body, or it gives a body the "Superman Effect." The person may feel as if they are able to do more that they normally would.  Caffeine belongs to a group of chemicals called xanthines. This includes theophylline and theobromine. Xanthine stimulates the central nervous system. This can cause people to feel restless, nervous, and unable to fall asleep. Some people believe caffeinated soda gives people hiccups, this is not possible, but the soda itself may. Although caffeine may increase chances of headache and migraines dramatically decreasing caffeine intake may also get headaches. However, this may be a result of not drinking enough water.  Some symptoms of too much caffeine are headache, tremor, nervousness, irritability, and loss of sleep. These symptoms apply to almost all people, especially young children. It also takes only 15 to 20 minutes for caffeine to get in the blood and lasts around 3 1/2 hours.      SUMMARY  Caffeine is found in many substances and is considered a stimulant. It speeds heart rate, and circulation.   Daphnia are small crustaceans, and are vital to the heath of fish and marine animals.

BIBLIOGRAPHY Bayer M., Barbara "Caffeine" World Book Encyclopedia. 1999. Vol. 2 pp. 14 "Water Flea" Encarta. 2000  "Caffeine" Encarta. 2000 "Everything You Need To Know about Caffeine." [Online] Available http://ificinfo.health.org/brochure/caffeine/htm McLaughlin, P.A. "Water Flea" World Book Encyclopedia. 1999. Vol. 21 pp. 134 Orlans, Barbara F. Animal Care From Protoza to Small Mammals Menlo Park, California Addison-Westly Publishing, 1977. Pp. 95-98 Schumann, Kia "Daphnia FAQ-Prototype"  [Online] Available http://freshaqarium.about.com/pets/freshaqarium/gi/dynamic/offsite.htm?site=http%3A%2F%2Fwww.ee.pdx.edu%2F%7Edavidr%2Fdiscus%2Farticles%2Fdaphnia.html

 I would like to thank the following people for their contributions toward my science project possible and successful. 

First I would like to thank Mr. Francis Sweeney, the director of King County Environmental Labs in Seattle, for prodcking daphnia pulex for my project.
Second, I like to thank my science teachers , Mr. Ken Newkirk, Mrs. Rita Packacale, and Mrs. Sharron Cooley for helping me with my project and making it able for my project to be successful. I would like also to thank them for taking our bio. pictures. 
Lastly I would like to thank my classmates Lacey T., Vanessa W., and Nichole A. for helping me when they saw my mistakes. 
 
 

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