Katherine Leaver December 10, 2012 Environmental Systems &Societies Internal Assessment #1 (Widewater Fieldstudy)
Dissolved oxygen is the biogeochemical level that is tested in this study. Oxygen is a byproduct of photosynthesis in plants. Oxygen is vital for all living things. Respiration by aquatic animals, decomposition, and other chemical reactions consume oxygen. An e xample would be wastewater contains organic materials which are decomposed, using oxygen in the process. Other sources include runoff, and septic systems. Oxygen is measured in its dissolved form as dissolved oxygen (DO). Aquatic animals are very sensitive to DO levels. DO is measured by in milligrams per liter. Milligrams per liter are the amount of oxygen in a liter of water. DO is determined by the Winkler method. The Winkler method is performed by filling a sample tube completely, no air bubbles at all. Then a series of drops are added to the water, which then change the color in accordance to the DO level.
The climate in Virginia is variable. In the area studied, the average high for November is 59° F and the average low is 37° 37 ° F (15° C and 2.78° C respectively). The average rainfall for the area is 3.61 inches (9.17cm). There are five distinct climate re gions in Virginia; the Tidewater region, the Piedmont region, Northern Virginia, Western Mountains, and Southwestern Mountains.
Previous results indicate cold water will contain more DO than warmer waters. DO rates fluctuate with water temperature and diurnally. If DO levels drop below unhealthy levels, the body of water will begin the process of eutrophication, or the excessive growth of algae. The algae then dies and DO levels drop, killing all living things in the water.
Katherine Leaver December 10, 2012 Research Question
Is there a correlation between dissolved oxygen levels and the water temperature?
Hypothesis
If the temperature of the water increases, then the dissolved oxygen levels will decrease.
Data Section
Independent Variable (IV): Temperature
The IV was difficult to isolate because the temperature will rise by itself, with t he air temperature.
Dependent Variable: Dissolved oxygen levels
The DV will change in accordance to the change in temperature. There will be a negative correlation between the temperature and the DO levels.
Katherine Leaver December 10, 2012 Controlled Variables: Locations measured, amount of water collected, depth water is collected at, and, how water is collected
I will do my best to c ontrol everything I can, including how deep the DO bottle is submerged, completely fill the dissolved oxygen bottles for later testing, and the location at which the atmospheric conditions are measured. I will submerge t he DO bottle and shake it for 5 seconds to remove all air bubbles.
Extraneous Variables: Atmospheric conditions, organisms in water, how fast the temperature rises, and, people in the water (in boats).
These variables I cannot control. The actual weather, including temperature, humidity, wind speed, and barometric pressure. There ar e organisms in the water tested, which w hich cannot be controlled. There are other students at the field, so I cannot control the location I am testing, for everyone can access the pond. Also, there are private properties on the edge of the field, which all produce pollution affecting the whole area.
Abiotic factors: Pollution and atmospheric c onditions
The abiotic factors in the environment include atmospheric conditions and pollution. There is private property located on the e dge of the field. Those houses are all sources of pollution, be it heat pollution, light pollution, and physical sources such as trash. Pollution is important, because pollution affects organisms and photosynthetic plants, who cannot survive, then that changes t he biochemical oxygen demand.
Katherine Leaver December 10, 2012
Biotic factors: Organisms in the water, c hemical processes, and, decomposing or decomposed matter in the water
There are several biotic factors at the testing site. One big example are organisms in the water. There will be humans, fish, and other organisms all producing heat in the water, which will raise the temperature. Also, aquatic organisms will use the DO to preform cellular respiration and deplete the D O levels, which are replaced by t he photosynthetic plants (Called the BOD or biochemical oxygen demand). The chemical processes all take DO t o complete the reactions. And decomposing or decomposed matte r produce oxygen as a byproduct.
I will have 10 recorded points of where I took the water samples, and 10 recorded points on where I recorded the atmospheric conditions on land. The land conditions will be on the chart with the letter “a” after the trial number. The water samples will be on the chart with the letter “b” after the trial
number. I will use the DO testing test ing kit to perform the tests t ests after gathering the samples. I will be using a thermometer (connected to a LabQuest), a barometer, and an anemometer.
Materials
10 labeled dissolved oxygen bottles
LabQuest with relative humidity and temperature probes.
Dissolved oxygen testing kit
Katherine Leaver December 10, 2012
Anemometer
Lab sheet to record all data
Pen/pencil
GPS (The one used in this experiment had a ±6 meter accuracy)
Raw Data
Land Conditions
Water Conditions and Results of the Testing
Katherine Leaver December 10, 2012 Pictures of the Testing
Katherine Leaver December 10, 2012 Map Generated on ArcView GIS
±6 Meter accuracy
Katherine Leaver December 10, 2012 Standard Deviation of Test Results
Average Temperature: 6.456°C
Variance: 0.502778
Standard Deviance: 2.0055483
Conclusion
The problem investigated in this study was the effect of temperature on dissolved oxygen levels. My hypothesis was that the cooler water would hold more dissolved oxygen. The study was inconclusive. I made several mistakes, and there were technological problems. I created a g ap in the data when I went to help a classmate with his project. I also dropped a DO bottle before using. And, the GPS I used deleted a waypoint, which I couldn’t recover. If I could change the experiment, I would
change the data sheet. The format I was using got complicated. I would also not use a LabQuest. I would use manual thermometers, psychrometers, and anemometers.
Katherine Leaver December 10, 2012
Sources
"5.2 Dissolved Oxygen and Biochemical Oxygen Demand." United States Environmental Protection Agency. United States Government, 06 Mar . 2012. Web. 17 Nov. 2012. .
"Monthly Weather Forecast for Stafford, VA (22556) - Weather.com." Weather.com. The Weather
Channel, 18 Nov. 2012. Web. 18 Nov. 2012.
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"Virginia Climate." Virginia Is for Lovers. 11 Apr. 2011. W eb. 10 Dec. 2012.
Katherine Leaver December 10, 2012 Hayden, Bruce P., and Patrick J. Michaels. "Virginia Climate Description." Virginia Climate Description. 20 Jan. 2000. Web. 10 Dec. 2012.
Perlman, Howard. "Water Properties: Dissolved Oxygen." Dissolved Oxygen, from USGS Water Science for Schools: All about Water. 31 Oct. 2012. Web. 10 Dec. 2012.
