Water girl: one teen's science project earns her fame and helps to clean up a polluted river.
That concerned Shannon, who knew that a polluted river can make a lethal home for fish and other wildlife. Plus, the Spanish Fork River was dumping its dirtied water into Utah Lake, which is habitat for endangered species. "The June Sucker is an endangered species of fish that only exists in Utah Lake," says Shannon. She wondered if human activity along the river was to blame for the pollution.
Shannon began her project by researching which water-quality properties she should test. For example, by measuring the amount of oxygen (O) dissolved in the water, she would learn whether or not fish, such as the June Sucker, could survive there. In general, a polluted river contains less oxygen than a healthy one. Sewage from treatment plants, for instance, can carry organic matter into a river. As that carbon-rich matter breaks down, it consumes oxygen. Too much pollution can deplete the water's oxygen.
But a measure of dissolved oxygen wouldn't tell her the cause of the pollution. For that, Shannon would measure the concentration of chemicals such as nitrogen (N) and phosphorus (P). Certain forms of these chemicals come from products that humans use such as farm and lawn fertilizers, as well as from household detergents.
Based on her research, Shannon developed a hypothesis, or a possible answer to a scientific question.
Human activity is the major factor that is causing the decline in water quality along the Spanish Fork River.
Before getting her feet wet, Shannon needed to choose her sampling spots. To pinpoint where the pollution was coming from and what was causing it, she decided to set up seven sampling sites along the river. "I wasn't sure of where humans were polluting the river. So I set up different test sites," explains Shannon. Then she designed a procedure, or list of steps for her experiment. Below, Shannon shares the steps to a winning procedure.
[check] Decide what materials you need for your experiment. Make a detailed list that includes amounts and measurements.
[check] Define your control, or standard against which you will compare your results. Shannon compared her water-quality measurements with the Utah Environmental Protection Agency (EPA) guidelines for cold-water fisheries.
[check] Identify your independent variable, or the factor that you change during your experiment. Shannon's independent variable is the sampling site along the river.
[check] Determine your dependent variable, or the factor that responds to the change in the independent variable. In Shannon's study, the dependent variable is the level of each water-quality indicator, including the concentration of dissolved oxygen.
[check] Keep all other variables constant. The independent variable should be the only changing factor in your experiment. In Shannon's project, the time of day could impact the levels of chemicals in the water. For instance, algae carry out photosynthesis during the day. When these plantlike organisms make food by capturing sunlight to turn carbon dioxide and water into sugars, they also release oxygen into the water. So Shannon always took her measurements at the same time of day.
[check] Repeat the experiment. Conduct several trials. If you get similar results among your
trials, your conclusions will be more reliable. Shannon collected water-quality samples along the Spanish Fork River once a month for six months.
LIST OF MATERIALS
* 1 Pair of wading boots
* Set of old clothes
* Map of Spanish Fork River showing test sites
* 1 Dissolved oxygen test kit
* Pencil and paper
* 21 Water-collection tubes
* 1 Nitrogen test kit
* 1 Phosphorus test kit
* 1 Dip net
* 7 Glass jars
* 7 Labels for glass jars
* Ice chest filled with ice
* Tape measure
* Species identification books
1 Wake up at 4 a.m. Put on wading boots and old clothes. Pack field equipment.
2 Head to a test site and collect a tube of water. Use the test kit to analyze the water for dissolved oxygen. Record results.
3 Repeat Step 2 for each site--before sunrise. (Note: When the sun rises, the algae will start to photosynthesize and release oxygen. This extra oxygen could throw off the test results.)
4 Return to the first site and collect two tubes of water. Use the chemical test kits to analyze one tube for nitrogen, and the other for phosphorus. Record results.
5 Sweep a dip net through the water in a small area to collect any macro-invertebrates, or animals without a backbone that can be seen without a microscope. Pick out any organisms from the net, and put them into a glass jar. Fill the jar with river water. Label the jar with the site location and time of day. Place the closed jar into an ice chest. "Macro-invertebrates can tell you things that your test kits may not pick up," says Shannon. For instance, water boatman bugs can live in low-oxygen water, but stonefly larvae need plenty of oxygen.
6 With a tape measure, find the width of the river at the site.
7 Repeat Steps 4 through 6 for the other six sites.
8 Repeat Steps 1 through 7, once a month for six months.
9 Compile data and reach conclusions.
At the end of her study, Shannon found some troubling results. "Every site broke the state EPA standards [for water quality]," says Shannon. She found that humans are to blame. Her data showed high levels of chemicals from fertilizers, sewage, and household detergents.
On the bright side, Shannon's river mucking paid off: Her project nabbed first place in the Intel Science Talent Search, a national competition. Now she is educating students about ways to protect water quality. And she hopes to continue her environmental studies when she enters Utah State University next year.
For more on Shannon's river project, visit: www.amnh.org/ nationalcenter/ youngnaturalistawards/ 2005/Shannon.html
MINI LAB: Shannon examines a water sample. Chemicals in the tube turn the sample different colors to indicate the nitrogen level.
After collecting her data, Shannon created charts and graphs for her poster display. Her organizational techniques wowed the judges at the Intel Science Talent Search. Shannon also presented her project poster to the Utah State Water Quality Board.
MYSTERY MUD Shannon sorts through the material collected in her dip net, picking out the hidden macro-invertebrates from the mud and grasses. She will store these in an ice chest so she can identify the insects back at home.
DIMENSIONS At each sit Shannon collects as much information as possible. For instance, she uses a tape measure to find the width of the river at each site. That will help her figure out how much habitat exists for wildlife such as fish.
SORTING BUGS At each site along the river, Shannon collects macro-invertebrates. Since these insects are so tiny, she sometimes needs a pipette, a tool that is similar to an eyedropper, to pick out individual insects.
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|Date:||Sep 18, 2006|
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