Animal Oxygen Consumption - Lab Report Example

Animal Oxygen Consumption Lab Report This laboratory activity is concerned about energy metabolism absorbed in the energy production among animals which were used as subjects of the study. Primarily, it demonstrated relationship of the subjects' body weight, oxygen consumption per body weight at certain incubation periods. It also provided opportunities for students to perform accurately the procedures in the use of LaMotte Dissolved Oxygen kit, titrations and balance and allowed them to compare the oxygen consumption among organisms. The laboratory activity is practically experimental, were experimental and control group designs have been applied. After series of tests and manipulation, the investigator found out that, oxygen consumption of the group's subject which is the "Tilapia" increases, as incubation period increases; however, the former was found to have no direct relationship with its body weight. The result was contrasting to the experience of other groups which were assigned to investigate "crayfishes". Direct or linear relationship among crayfishes' oxygen consumption, incubation time and body weight were not as well established. Introduction All living cells need energy from exterior sources to act upon their many important tasks such as biosynthesis, transportation of molecules across membranes, movement, and reproduction. Green plants for example, acquire vast amount of energy from sunlight through photosynthesis. Chloroplasts surrounding the cell matrix convert solar energy into chemical energy. Moreover, most animals ingest food (usually plants and other animals) to acquire chemical energy that are stored in the food at the same time generate ATP through a process called cellular respiration. Cellular respiration in the same manner requires oxygen as a reactant. Thus, as an outcome of cellular respiration and cellular activity, animals are able to produce and release heat. This is one of the many unique characteristics of organisms and they as well vary in the rate of heat production as part of their metabolism. The overall process of cellular respiration can be summarized as: C6H12O6 + 6 O2 6 CO2 + 6 H2O + ATP + heat (Foodstuff) (respiration) (heat) (work) Oxygen consumption was measured by estimating the energy metabolism, since the rate of oxygen consumption as well as energy utilization is generally directly related. In this exercise, the oxygen consumption of Tilapia was determined by using LaMotte Dissolved Oxygen kit in small volumes of water. This technique is titration-based on the oxidizing characteristics of dissolved oxygen (DO). Manganese solution is also added to the tested water samples followed by a strong alkali. Later, the solution was titrated through a standard solution, followed by addition of an indicator. Objectives The laboratory activity intended to achieve the following aims: 1. To demonstrate relationship in animals' body weight, oxygen consumption per body weight with respect to the incubation periods. 2. To perform accurately the procedures in the use of LaMotte Dissolved Oxygen kit, titrations and balance. 3. To compare the oxygen consumption of nektonic and benthic organisms. Hypothesis There is no direct relationship among oxygen consumption, incubation time and body weight for both animals (tilapia and crayfish). Methods/Procedures 1. Students are assigned into groups. Each group will be assigned and organism to work with depending on availability. 2. Fill 4 jars with the aquarium water. Using a net, select 3 animals of which your group is assigned to and gently transfer them one to each of the mason jars. The animals may vary in size. In addition, in the case of Tilapia, choose smaller ones so they have room to move about in the jar. *Collect water for your negative control first, since the incubation period is 2 hours long. 3. Weigh all three animals by removing them one at a time, from the jar, pet dry on a paper towel, and place on a scale. The entire procedure must be quick yet gentle. Disturb the animals as little as possible. Overly agitated animals will affect your experiment results. Record their body weight in Table 4.1 4. Place the three jars with animals and one jar without an animal into the large aquarium. Fill each jar to the top without bubbling water and seal the jars under water. The fourth jar with water but without animal is the control. Turn the jars upside down to ensure that no bubbles are trapped in the jars. Record the time and this your time 0. 5. The three jars with animals are to be incubated for 1, 1.5, and 2 hrs, starting from the time 0 you previously recorded. The negative control jar (without animal) is to be incubated for 2 hrs. 6. While incubating the 4 jars, fill a LaMotte water sampling bottle provided with the kit with the aquarium water the same way you fill in the mason jars. Titrate the initial Winkler water sampling bottle with instructions below and record your data. This is your initial (time 0) sample. It is assumed that the initial water sample will give the initial oxygen concentration. Over the incubation period, the organism in the jar should consume oxygen in the sealed jar. a. Fill water sampling bottle with the water to be tested. b. Add 8 drops of Manganous Sulfate Solution. c. Add 8 drops of Alkaline Potassium Iodine Azide. d. Cap and mix. Allow precipitate to settle. e. Use the 1.0 g spoon to add Sulfamic Acid Powder. f. Cap and mix until reagent and precipitation dissolve. g. Fill test tube (provided with the kit) with solution to the 20 ml line. h. Fill the titrator syringe with 0.025 N Sodium Thiosulfate to the 1 ml (marked 10) line. i. Titrate until sample color is pale yellow. Do not disturb titrator. j. Add 8 drops of starch indicator. The solution should turn blue. k. Continue titrating using the same titrator syringe (without refilling) until blue color just disappears and solution is colorless. l. Read the number on the titrator syringe (in ppm dissolved oxygen). If you use more than one titrator of Sodium Thiosulfate, make sure you also add the number of syringe used. For example, if the syringe reads 7 (with 3 left in the syringe), the water titrated contains 7 ppm of oxygen. If you used one full syringe plus 7 in the second syringe (with 3 left), the water contains 17 ppm of oxygen. 7. When each of the time periods is reached, fill a Winkler water sampling bottle with water from the jar without bubbling the water or causing bubbles in the water containing the organism. Fix and titrate each of the samples using the same instructions described earlier. Each person in your group should titrate a sample. After titrating the water, you can release the animal gently back into the aquarium. 8. By the end of the experiment, your group will have titrated 5 water samples: the initial 0 hr (no animal), 1 hr, 1.5 hrs, 2 hrs (with animals), and the 2 hr control (no animal). 9. Pool data of other animals from your classmates. You are to write a formal lab report for this experiment. You need to include all data from this lab in your report. 10. To calculate the oxygen consumed by each animal in the jar, subtract the final oxygen value in ppm by the initial oxygen value in each jar. The difference between the initial and the amount left in the water is assumed to be the amount of oxygen consumed by the animal during this period of time. Do the calculations in Table 7.2. 11. Divide the amount of oxygen consumed by the body weight of the animal in each jar. Do this calculation in Table 7.3. Now the amount of oxygen consumed is adjusted by the animal body weight, what can you conclude about the amount of oxygen consumed and the incubation time 12. Now divide each value by the incubation time such as 1, 1.5 and 2 hrs in Table 7.4. Notice that the units have changed in each table. Now the amount of oxygen consumed is adjusted by both the body weight and the incubation time, what can you conclude about the amount of oxygen consumed per g in the same period of time 13. Plot your results into two graphs. What conclusions can you draw from the two graphs a. Figure 1 with body weight (g) on the x axis and oxygen consumption per body weight per hr (ppm/g/hr) on the y axis. You should have one line for each type of animal. b. Figure 2 with time (hr) on the x axis and oxygen consumption per body weight per hr (ppm/g/hr) on the y axis. You should have one line for each type of animal. Materials Cray fish and Tilapia Aquarium water with fish LaMotte titrating kit One large control tank with water Scale Weighing boat Results and Discussions Table 7.2. Oxygen Consumption of the Animals in Each Jar 1 hr 1.5 hr 2.0 hr Group Animal O2 ppm bw g O2 ppm bw g O2 ppm bw g Example Tilapia 8.4 - 8.0 = 0.4 10.2 0.6 9.5 0.9 9.8 1 Tilapia 8.1 - 3.0 = 4.9 46.29 8.1 - 1.0 = 7.1 35.98 8.1 - 0.5 = 7.6 36.12 The data in the above table shows the Oxygen Consumption of the Tilapia in each jar with respect to the given incubation time. It can be noted that as the incubation time progressed, 1.0 hour, 1.5 hours and 2.0 hours respectively, the Oxygen Consumption also increases (4.9 ppm, 7.1 ppm, and 7.6 ppm respectively). On the other hand, the amount of body weight (in grams) which required oxygen lessened (46.29 g, 35.95 g, and 36.12 g) and later varied as incubation period is increased. Sardella, et. al. (2004) in their investigation on indicators among Californian Tilapia said that, oxygen consumption rate (O2), as measured according to the techniques of Gonzalez and McDonald (1994), can decrease with salinity. Their rate of oxygen consumption as measured in tilapia hybrids became accustomed for 2 weeks to 35, 55, 75 or 95 g l-1 salinity. Table 7.3 Oxygen Consumption of the Animals per gram of Body Weight in Each Jar 1 hr 1.5 hr 2.0 hr Control Group Animal O2 consumed per g bw ppm/g O2 consumed per g bw ppm/g O2 consumed per g bw ppm/g Example Tilapia 0.4 / 10.2 = 0.0392 0.0632 0.0918 1 Tilapia 4.9 / 46.29 = 0.106 7.1 / 35.98 = 0.195 0.195 / 1.5 = 0.130 7.6 / 36.12 = 0.210 0.210 / 2.0 = 0.105 8.2 2 Tilapia 0.2177 0.1975 0.1763 8.2 3 Crayfish 0.137 0.012 0.053 7.6 4 Crayfish 0.244 0.146 0.255 9.3 Subsequently, Table 7.3 has reflected the relationship among the body weight of the animal in each jar, amount of oxygen consumed by the animals and the incubation period. The 1st group who used "Tilapia" in the demonstration of the Oxygen Consumption per g bw revealed that, Oxygen Consumption noticeably decreased per gram body weight as incubation period increases with values presented randomly: 0.106 ppm/g during the 1st hour, 0.130 ppm/g after 1.5 hour, 0.105 ppm/g after and 2.0 hour respectively. The control set up obtained the value which is 8.2 ppm/g. For the 2nd group who also utilized "Tilapia" in the demonstration of the Oxygen Consumption per g bw, it can be observed that during the initial incubation time (1 hr), the oxygen consumption is quite higher than the rest of the values obtained. But during the succeeding incubation periods, there was also dramatic decline in the oxygen consumption, the same as noted in the activity of the first group. The following are the respective values of the said oxygen consumption per gram body weight: 0.2177 ppm/g, 0.1975 ppm/g, and 0.1763 ppm/g. and 8.2 ppm/g for the control set-up. Sample Crayfish Tilapia Photo condensed from Minnesota Photo condensed from Fishyfishing.com Pollution Control Agency, 2009 On the contrary, the 3rd group who considered "Crayfish" as the subject of the study yield a different pattern of results. After the tests, the following data were collected from the experimental group: 0.137 ppm/g, 0.012 ppm/g,and 0.053 ppm/g respectively. The control group yield 7.6 ppm/g. There is an irregular pattern in the oxygen consumption with respect to the incubation time and the value under the control set up is lower as compared to the values of groups 1 and 2 that utilized "Tilapia" as their experimental subject. Group 4 also verified the results of Group 3 as far as experimental set up is concerned. The data gathered for oxygen consumption with respect to the incubation time also reflected an irregular pattern. The direct relationship could not be established and the value of oxygen consumption in the control group is highest at 9.3 ppm/g while the experimental set up obtained: 0.244 ppm/g, 0.146 ppm/g, and 0.255 ppm/g respectively. There are studies which have shown that, the rate of consumed oxygen is directly proportional to the organisms' weight. Meaning to say, larger animals usually consume larger quantity of oxygen than the smaller ones. However, as far as metabolic data is concerned, particularly if expressed in terms of rate of oxygen consumption per unit weight, there is opposite trend that is found. Smaller organisms consume extra oxygen per gram of body weight than bigger animals do (Andre, 2004). Oxygen consumption in every species increases indirectly as a role or function of its weight, the surface area is considered an exponential function of the body weight. Biologists have then suggested that, metabolic demands of a certain animal are a direct function of one's surface area (Stark, 2008). They also added that, temperature also affects metabolic reactions. The body temperature of dynamic or active animals varies from -2C to +50C. Temperature is a significant physical property of the environment; this indicator measures the motion as well as kinetic energy of molecules. Conclusion: Based on the aforementioned findings of the lab activity, oxygen consumption of the group's subject, which is the "Tilapia" increases, as incubation period increases; however, the former was found to have no direct relationship with its body weight. The result was contrasting to the experience of other groups which were assigned to investigate "crayfishes". Direct or linear relationship among crayfishes' oxygen consumption, incubation time and body weight were not as well established. Guide Questions 1. If your control has a very different oxygen value after 2 hrs compared to the initial value, what are possible explanations As previously mentioned, oxygen consumption among animals increase indirectly, as a role or function of its weight. The surface area and other environmental factors can affect the outcome or may have interplayed in the process. According to Stark, metabolic demands of a certain animal are a direct function of one's surface area. 2. How could one correct/adjust your data for consumption or production of oxygen in the control An oxygen electrode may be used. It has a calibrator by which utilizes temperature as an independent factor to control the amount of oxygen in water. It can manipulate oxygen pressure in the air. 3. What other organisms could be consuming or producing oxygen Plants may also be used in the experiment. 4. In theory, what relationship is demonstrated between oxygen consumption per body weight per hr (ppm/g/hr) and size of animals (g) According to your Figure 1, was this demonstrated in your data Explain the differences in oxygen consumption of species you used. There is direct relationship. Yes it was demonstrated in the data, particularly on data collected from investigation on Tilapia. Since this animals are active there are more likely to have higher cellular activity, thus, able to produce and release more heat, which resulted to more consumption of oxygen. 5. In theory, what relationship is demonstrated between oxygen consumption per body weight per hr (ppm/g/hr) over time (hr) According to Figure 2, was this relationship demonstrated in your data Explain the differences in consumption of species. 6. Compare the different habitats of the animals we used in the experiment. In theory, should a crawling and benthic (bottom) organism such as a crayfish have a lower oxygen consumption than a nektonic swimming organism such as Tilapia Does your data show the same References Gonzalez, R. and Mcdonald, D. (1994). The relationship between oxygen uptake and ion loss in fish from diverse habitats. Journal of. Experimental. Biology, 190, 95 -108. Minnesota Pollution Control Agency, (2009) Crayfish. St. Paul, MN 55155-4194 Retrieved March 16, 2009 from http://images.search.yahoo.com/images/viewback=http%3A%2F%2Fimages.search.yahoo.com%2Fsearch%2Fimages%3Fei%3DUTF-8%26p%3Dcrayfish%26y%3DSearch%26fp_ip%3DPH%26fr2%3Dtab-web%26fr%3Dfptb-yff3&w=256&h=263&imgurl=www.pca.state.mn.us%2Fartwork%2Fkids%2Fcrayfish.jpg&rurl=http%3A%2F%2Fwww.pca.state.mn.us%2Fkids%2Fc-december.html&size=16.6kB&name=crayfish.jpg&p=crayfish&type=JPG&oid=aac9badb869e24dc&no=2&tt=100,931&sigr=11f45718t&sigi=11ddaut19&sigb=13biir9s5 Sardella, B. A., Matey, V., Cooper, J, Gonzalez, R.J., and Brauner, C.J. (2004). Physiological, biochemical and morphological indicators of osmoregulatory stress in California' Mozambique tilapia (Oreochromis mossambicus x O. urolepis hornorum) exposed to hypersaline water Journal of Experimental Biology 207, 1399-1413. Stark, W. S. (2008) The effects of temperature and body size on crayfish metabolism. St. Louie University Website, MO 63108 Retrieved March 16, 2009 from http://starklab.slu.edu/PhysioLab/PHYSIOLO.htm The Fishing Guide (2008) Nile tilapia (Oreochromis niloticus). 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