The Nicotine's Effect on daphnia

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12/28/2012 - 10:30

Lab Report: The Nicotine's Effect on daphnia

Daphnia is a remarkably tiny organism under the planktonic crustaceans classification and also called water fleas. They have a length between 0.2 to 0.5 mm. They have a hard transparent skeleton, which resembles a shell. They are common aquatic organism because they have the capacity to adapt different aquatic environments ranging from freshwaters to acidic swamps, lakes, seas, rivers, wells and ponds. If one studies the effect of nicotine on Daphnia, the ultimate results are fatal (Fitzgerald 12). They are significant sources of food to different organism such as fish and frogs among others. Daphnia is common in laboratory experiments and have been used for years especially in drug tests among others. The most common test done using this organism is the Daphnia Heart Rate Test. Daphnia is ideal in Heart Rate Test because they are ectotherms, thus their body changes with changes in the environment. Following the fact that chemical reactions rate’s increases with an increase in temperature, it would of great use in establishing the temperature changes if Daphnias’ metabolism rate would be increased.

This experiment aims at designing a hypothesis about the effect of nicotine on living organisms. The heart of Daphnia is clearly seen with the help of a low power microscope. In reference with research, which states the heart of a Daphnia beats 300 beats per minute, we can have a chance to monitor the change of the heartbeat, with change in different physiological aspects such as chemical concentration, temperature, or changing the type of chemical or even the reaction when Daphnia are in pure water. It is necessary to note that the change in Daphnia heartbeat rate does note practically represent the human’s case. However, the examination will give us learners a chance to evaluate the effects of nicotine on metabolic processes. This experiment is under the courtesy of British Pharmacology Society (Corotto, Ceballos and Vinson, 177).

In this experiment, Daphnia magna, which is a transparent crustacean is used to establish the effect of nicotine on heart rate. There are different results expected from the experiment based on the concentrations of the nicotine. However, because nicotine is a stimulant, thus increase metabolic rates, there are high possibilities that the heart rate will increase with the increase in the concentration of nicotine. Ultimately, the Daphnia may die because of high heart rates, as this is a fatal condition (Fitzgerald 15).
Problem: what effect will nicotine have on Daphnia?

Ethical issues
Students should be very careful because they are expected to handle these animals in a way that illustrates good ethical attitude towards experimental animals. High is regardless of the fact that they are animals with fewer capabilities thus may not suffer as much as higher animals; overall they deserve respect. All animals should be returned to their habitats after the experiment. This will support ethical approaches put in place by different biology organizations.

1. Tobacco solution
2. 2 depression slides
3. 2 cover slips (22 x 60 mm)
4. Kleenex
5. Water from Daphnia culture of different temperature
6. Piece of cotton wool
7. Microscope – low power resolution
8. Daphnia Magna – culture of water flea
9. Daphnia anatomy chart- for source
10. 3 droppers

Preparation of Tobacco solution
This solution can be made from cigarettes; approximately 20 of them can make an ideal solution. After the extract is emptied in a cup of water, place it covered for about 12 hours. Sieve the solution into another container; solutions of differing concentration should then be made where the different shall be determined by the ratio between water and the solution. The study will begin using solution with lower concentration and later use those with higher concentration in references with the guidelines by Washington Association for Biomedical Research.
It is significant to note that the level of nicotine varies from cigarettes to cigarette. The cigarettes that have the highest level of nicotine are those 1.7 mg/cigarettes while those with the lowest have a concentration of 0.3 mg/cigarette. With this knowledge, one may know which brands to use when they are targeting high concentrated nicotine and what to use when targeting low concentration nicotine (Corotto, Ceballos and Vinson, 173).

1) Label all the containers as follows: nicotine solution, Daphnia water, rinse water. Also, mark all the droppers. Always return the droppers to their containers or place them next to their containers to avoid contaminating different solutions.
2) Use the Daphnia dropper the get hold of the Daphnia and place it on the slide; remember to have some Daphnia water around. Keenly observe the organism under the microscope on a low light. This will help in familiarizing oneself with the position of the heart as well as the whole body of the organism. To enhance tracing its position, turn off the light when you are directly observing the Daphnia. This will also prevent warming the Daphnia and one may alter with the metabolism of the organism with increase in temperature. You should not proceed with the experiment until the animal get used to the life on the slide; his may take two to three minutes. After the organism has fully settled on the slide, gently cover the slide with the cover slip as this will hold the Daphnia in a fixed position.
3) Record all the observations specifically the nature of the heart bit as well as other important information.
4) Suck some nicotine into the dropper.
5) After the Daphnia has settled, gentle remove the cover slip and sponge the fluids around the Daphnia using the cotton wool; be careful not to touch the Daphnia. To enhance this, place the Daphnia in a Kleenex liquid, and clean the other section.
6) Get ready to place some nicotine in the depression slide, having in mind that the Daphnia cannot survive with absence of the liquid.
7) Wait for one to two minutes after applying the nicotine solution before recording the observation. If the heart is still beating after making observations, remove the animal and deep it is a small dish containing the original aquarium.
8) Repeat the same procedure using solutions of different concentrations with different Daphnia. One should perform a minimum of three experiments; this will ensure that the resultant results are correct.
NB: observations can be made without covering the Daphnia with a slip as this will give an opportunity to make varying observations; the daphnia will be having a free space to make small movements. Important information such as how long it takes before it stop making movements should be recorded in every set of the experiment.

It was observed that the average heartbeat rate of a Daphnia is 354 beats in a minute. With varying levels of concentration of nicotine, the heartbeat varied from 91 beats to 521 beats in a minute. It was also noted that the varying rates of the heart was not attributed by the size of the specimen (Corotto, Ceballos and Vinson, 174).

Nicotine Heart beat
Percentage of initial Concentration of nicotine BMP
First trial 0.0 mM Nicotine 357
Second trial 0.5 mM Nicotine 458
Forth trial 50 mM Nicotine 234

On average, a Daphnia has an average heartbeat of 354 beats per minute. However, there is some minimal variations in the rate of heart beat with the size of the animal. The bigger Daphnias have a lower rate than the smaller one. It is therefore crucial to use animals of the same size to have reliable results. The linear graph above shows that an increase in the concentration increases the rate of the heartbeat. However, higher concentrations are fatal and may kill the organism as they raise the rate of metabolism to a level where Daphnias cannot withstand; this thereby reduces the rate of the heartbeat because the animal is growing weaker and weaker. This is also evident from the observations that Daphnia makes more movements with little concentrations, but when nicotine of higher concentrations is introduced, movements increases and then drops suddenly. This shows that the specimen is more active in low concentrations and less active at higher concentrations.
In reference with the observations made when the specimen was returned to its habitat, it is evident that one can reverse the metabolic reactions to the initial. This is following the fact that even after exposure to higher concentrations of nicotine, live Daphnia would still survive if returned before its heart stopped. However, concentrations of over 1 mM are irreversible. The specimen died when it was returned to its initial habitat. This is because there were some internal damages when it was exposed in the 50 mM concentration of nicotine.

Recommendations and Conclusions
Nicotine is a suitable reagent for the examination of the heartbeat rate of Daphnia. 5% to 10% are the recommended concentration, which cannot cause fatal effects to the organism. The concentration will however increase metabolic reaction, but will not lead to death. However, any further increase in concentration will kill the specimen. This information is highly significant for teaching laboratories, as they can know means in which to design their experiments when evaluating the effects of nicotine on heartbeat rate. We can confidently conclude that nicotine has a fatal effect on Daphnia. This is because it increases the metabolic reactions to undesirable levels (Corotto, Ceballos and Vinson, 174).

    Works cited
  1. Fitzgerald, K.F.,. "Alcohol and Tobacco: Will It Affect Your Heart?" California State Science Fair Abstract. Retrieved on 28th November 2012. Available at:
  2. Corotto, F., Ceballos, D. and Vinson, L. I N Q U I R Y &I N V E S T I G AT I O N: Making the Most of the Daphnia Heart Rate Lab: Optimizing the Use of Ethanol, Nicotine & Caffeine, 2010. 72, 3: 173-179. Available at: