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”Heart to Heart: Observations

of Daphnia Heart Rate in

Response to Ethanol,

Nicotine, and Caffeine”

Nick Dunn Charlie Oliver Austin Penna Kathleen Robertson

Outline

What are Daphnia? What is the relevance of experimentation with Daphnia heart rate? Similar Studies Hypothesis Methods Used Results and Data Discussion and Conclusion

Why is this study

relevant?

The effects of different toxins on Daphnia relate to the effects of pollution and water contaminants on the health of all living organisms. Harmful substances are regularly transfered between organisms via the food chain. Ethanol, Nicotine, and Caffeine are substances consumed by humans on a daily basis.

Similar Studies

Researchers, Campbell, Wann, and Matthews, tested the effects of lactose on Daphnia heart rate Results: Lactose inhibits heart rate by 30 – 100% and causes severe arrhythmia Students at North Georgia College and State University exposed Daphnia to club soda and isopropanol Results: Club soda temporarily decrease the heart rate Isopropanol significantly and permanently reduced the specie's heart rate

Methods – Grouping

Scheme

Wanted to test the effect of three different chemicals so had to create four different testing groups Each group contained 3 different samples so the data would be as accurate as possilbe One group included a negative control that would be exposed to no chemicals Every other group would be exposed to a set amount of each other chemical

Amount of Exposure to Chemicals

Each group was to be exposed to 150 mg of the specific substance Each group of three Daphnia had its own petri dish filled with water Control group had nothing added to its dish while others were exposed to a specific chemical for exactly three minutes Precise exposure time was acquired by starting a timer immediately after the Daphnia had been exposed and after three minutes had elapsed each Daphnia was taken out of the environment

Difference in Methods Between

First and Second Experiment

First time there was no nicotine and not enough Ethanol available First time there was no set amount of time that was planned for the Daphnia to remain in the chemical-contaminated environment First time the groupings each consisted of two Daphnia instead of three

Results

Chemical Trial 1 (bpm) Trial 2 (bpm) Trial 3 (bpm) Average (bpm) Control 313 306 327 315. Ethanol ( mg) 288 273 261 274 Nicotine (~ mg) 274 281 321 292 Caffeine (150 mg) 304 324 316 314.

Discussion of Results

Ethanol significantly depressed heart rate, decreasing average heart rate by over 41 bpm Caffeine did not have any notable effect on Daphnia heart rate. Nicotine mildly depressed heart rate, average decrease of 23 bpm. Observed spastic behavior similar to a seizure. Possibly due to another chemical from cigarette tobacco.

Notes and

Recommendations

Daphnia’s heart rate can be tough to count accurately, as it is small and beating fast. Required practice and adjustments in methodology to perform experiment. Recommend further tests with nicotine as an isolated chemical agent to determine if it is the cause of seizure-like behavior. Recommend further tests to determine why caffeine had no apparent effect on Daphnia, yet has profound effect in humans

Biological Relevance:

75- 150 mg of caffeine induces effects in humans for up to 2 hours Nicotine is highly toxic for aquatic organisms EPA Study : Death in 50 % of organisms exposed Ethanol reduces heart rate of freshwater fish Depletion of O 2 in aquatic environments

Continued:

Data is valuable for determining impact of these chemicals upon aquatic environments Effects upon other aquatic organisms may be inferred by change in Daphnia heart rate These common chemicals show detrimental long term effects in humans Effects upon microscopic and barely visible aquatic organisms are therefore serious

Works Cited

Benton, M., Chua, M., and Rowell, F. 2010. “Environmental Nicotine Contamination.” Forensic Science International. 200(1-3): 28-34. Campbell, A., Wann, K., and Matthews, S. 2004. "Lactose Causes Heart Arrhythmia in the Water Flea Daphnia Pulex." Comparative Biochemistry & Physiology Part B 139(2): 225-234. Corotto, F., Ceballos, D., Lee, A., Vinson, L. 2010. “Analysis of Daphnia Heart Rate.” American Biology Teacher. 72(3): 176-

Corvalan, C., Hales, S., and McMichael, A. 2005. “Ecosystems and Human Well-Being.” The International Journal of Public Health. 92(2): 6-10.