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Comparison of Dissolved Oxygen Content. Rachel Piening Ecology 303 Abstract Introduction Literature Review Methods and Materials Data and Results Conclusion References. ABSTRACT.
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Comparison of Dissolved Oxygen Content Rachel Piening Ecology 303 Abstract Introduction Literature Review Methods and Materials Data and Results Conclusion References
ABSTRACT • A water analysis was performed on the water of creeks around University of Cincinnati Clermont campus. These water samples were tested for dissolved oxygen content and then compared to the findings of the previous years. The results show that the oxygen content has changes over the years. Taking into account environmental factors and data from earlier labs this year, conclusions are made to why a change in dissolved oxygen levels has occurred.
INTRODUCTION • The environment and ecosystems are constantly changing. The weather, animals and even humans can play a role in the changing environment. Overtime plants decompose and regenerate. As new environments form, new habitats form and new species and organisms start to appear. The lab studies conducted in this class show these changes over the years. An interesting discovery is that of the dissolved oxygen content of the creeks and how it has changes over the years.
LITERATURE REVIEW • Dissolved oxygen in water is very important to aquatic life. These organisms need this oxygen to survive. Running water dissolves more oxygen than still water. DO levels can vary as a result of temperature, altitude and the time of day. During the afternoon hours is when DO levels are highest. Cold water will hold more oxygen and water holds less oxygen at higher altitudes. Water also gains oxygen from the atmosphere and from plants as a result of photosynthesis. However, aquatic animals and decomposition consume oxygen. Some sources of oxygen-consuming waste include runoff from farmland or urban streets. If more oxygen is consumed than produced then dissolved oxygen levels decline. Photosynthesis requires sunlight, but respiration and decomposition happen at all times of the day. This alone can create the variations in dissolved oxygen content.
LITERATURE REVIEW cont. • . Decreased levels of oxygen make it harder for aquatic organisms to live because it is vital for their survivability. The tiny oxygen bubbles are absorbed by these animals and transferred to their blood. In lab three water samples were taken, a sample from North Maple Creek, South Maple Creek and Dogwood Grove. Each was tested for dissolved oxygen content. Dogwood creek had the highest level and North Maple Creek had the lowest level. South Maple Creek results were similar to North Maple Creek. Past lab data shows that North Maple Creek once had the highest level of dissolves oxygen and Dogwood Grove had the least. These results represent the changing conditions of the Clermont Campus creeks.
METHODS AND MATERIALS • The water analysis protocol was used to test for the dissolved oxygen content in all three samples. Water was collected in a BOD jar and 2 mL of MnSO4 solution, alkali-iodide solution and conc. H2SO4 were added. The water was titrated with thiosulfate until a yellow-straw color was obtained. Using the measurement of thiosulfate used to complete the titration the dissolved oxygen content was able to be calculated. The O2 content is measured in mgO2/L H2O. The three samples from this lab and past lab data were used to compare results.
METHODS AND MATERIALS BOD jar containing water sample from South Maple Creek
METHODS AND MATERIALS 100 mL Erlenmeyer Flask of the water sample from South Maple Creek
RESULTS AND DATA • The Data from the previous years show that North Maple Creek had the highest level of dissolved oxygen and Dogwood Grove had the least. South Maple Creek had similar results to N. Maple Creek. Data from last week show that Dogwood Grove had the highest dissolved content and N. Maple Creek had the lowest level. Again S. Maple Creek had similar results to N. Maple Creek. The Data from previous years also report that protists such as, amoeba, and green alga were living in North Maple Creek. The Results showed neither Dogwood Grove nor South Maple Creek contained these protists.
RESULTS AND DATA cont. • The invertebrate and fauna sampling did not exhibit any relative characteristics as to why Dogwood Grove has the highest dissolved oxygen level. The same animals and insects were found in all three areas. Dogwood Grove had the lowest soil temperature according to the environmental factors lab. The temperature was 18o C. The other samples were 20o C. In the past the recorded temperatures were opposite, with North and South Maple Creek having soil temperatures of 13.56 and 16.67 respectively. However, Dogwood Grove had a recorded temperature of 13.89o C.
CONCLUSION • According to the results and data, there is not a specific explanation as to why the dissolved oxygen levels are highest in Dogwood Grove and lowest in North Maple Creek. In the past protists were observed living in North Maple Creek. This explains that North Maple Creek must have had high DO levels for these organisms to be able to survive. However, it does not explain why nor can there be a comparison to the current data because there is not data showing the presence of these protists. The soil temperature did not give any insight to the changing DO levels in the creeks. One reasoning could be that North and South Maple Creeks both have a slightly higher altitude when compared to Dogwood Grove. Water at higher altitudes holds less oxygen. The water in Dogwood Grove could be more rapidly flowing causing an increase dissolved levels. Also, there could be more decomposing materials near North and South Maple Creeks causing the DO levels to be lower.
REFERENCES • "5.2 Dissolved Oxygen and Biochemical Oxygen Demand." United States Enviornmental Protection Agency. Web. 23 May 2012. <http://water.epa.gov/type/rsl/monitoring/vms52.cfm>. • "Chapter 3 - Streams." Stream Dissolved Oxygen. Web. 23 May 2012. <http://www.ecy.wa.gov/programs/wq/plants/management/joysmanual/streamdo.html>. • Stein-Carter, Jan. "Ecology." Ecology. Lab Protocols. Class Data. 1995. Web. 24 May 2012. <http://biology.clc.uc.edu/courses/bio303/index.htm>.
