Identify | Hypothesis | Procedure | Collect | Analyze Data | Conclusion | Presentation
STEP 1: Identify Your Research Question
Amanda is a 10th grade student with a keen interest in her local streams and rivers. During soccer practice one day, she notices that a lawn care company is spraying a nearby field. A local stream runs along the border of the field and the property lines of many homes in the community. She has played along that stream all her life and wonders what effects the fertilizer has on the health of the stream. After some research, she finds that lawns and fields all along the stream are being treated with different chemicals to reduce the population of unwelcome dicots and lawn pests. She also learns that the stream is part of the watershed of a large estuary.
Amanda decides to conduct a study to find out how chemical treatment of nearby areas has affected stream biodiversity and if chemical treatment varies, how it affects stream diversity. She would like to identify a substance that would not harm the stream community. Stream life also depends on sediments deposited in the stream. Mary decides to measure the stream's turbidity to see if chemicals are leeching into the stream. Mary's final research question is: What effects do organic and inorganic fertilizers have on stream diversity?
STEP 2: Form a Hypothesis
Amanda researches what organisms would be expected in the local stream and identifies the chemical treatments performed on area fields and lawns near the stream. She finds that both organic and manmade chemicals are used to treat the areas. Common organic fertilizers used in this area include bone, blood, and feather meal or chicken droppings. Inorganic chemicals used include polycoated urea, nitrogen and phosphate compounds, sulfur, and other man-made chemicals. Her hypothesis is that the use of organic chemicals enables higher stream diversity than manmade chemicals.
STEP 3: Develop a Procedure
Amanda proposes her research procedure: She will conduct a survey in the community to determine which properties use what type of chemical lawn treatment. After determining the chemicals used or not used at each property in the community being surveyed, she will choose her research sample: 15 properties – five treated with organic chemicals, five treated with inorganic chemicals, and five that are untreated.
The stream will be studied at three different locations around each of the 15 chosen properties: (1) in the stream, 10 meters upstream from the center of the property; (2) in the stream, bordering the property; and (3) in the stream, 10 meters downstream from the center of the property. This will allow her to see if chemicals are traveling downstream. At each location, a one-square-meter plot will be measured in the stream for testing. She will also take a soil sample along the stream bank at each of the 15 sites. This will be done for 15 different properties, resulting in 45 study sites.
For each study site in the stream, she will complete the following tests:
- Stream velocity
- Fecal coliform bacteria
- Nitrate nitrogen
- Dissolved oxygen
- Macroinvertebrate species (These will be captured using dip and kick seine nets and by "washing" rocks. Species will be identified, populations will be counted, and the organisms will be released in the stream.)
- Chemical analysis of soil sample (including pH, nitrogen, phosphorus, and percent of organic matter)
STEP 4: Collect Your Data
Amanda organized the data for the 45 study sites using the following methods:
Journal: This included a record of each day spent in the field, including the following:
- Current weather conditions
- Previous day's weather
- Initial observations of study site
- Species name and number captured
- Notes (interesting or different observations than previously made)
Data Sheets: A data sheet was completed for each study site. Each data sheet was set up as a chart to record all the results of the tests performed at each site. Click here for a sample data sheet.
Map: A map of the local area was obtained to record the 15 different study sites. Each study site was divided into three subsites: A (upstream), B (border property), and C (downstream).
Plot: For each of the 45 sites studied in the stream, a plot was measured and staked that was 1 meter by 1 meter. All measurements were taken within this 1-square-meter plot.
Photographs: Photographs were included in the journal for each test site, providing a record of how close the chemically treated area was to the stream. Photographs were also taken of stream macroinvertebrates.
STEP 5: Analyze Your Data
Amanda analyzed the data from the 45 test plot sites and found that the temperature, pH, and turbidity were constant throughout the stream. There was no fecal coliform bacteria or chlorine at any location. Dissolved oxygen decreased in the B and C stream locations when organic nutrients were used. Organic nutrients also caused a slightly higher phosphate and nitrate concentration. More algae was located in the stream in these areas, and a lower number of Group III macroinvertebrates were counted.
The highest biodiversity of macroinvertebrates were found in test plots near properties that did not use any chemicals to treat their lawns.
Lawns and fields that had been treated with inorganic, low-nitrogen, or slow-release chemicals produced a smaller variety of diverse organisms but a higher number of each species captured.
Each of these test site plots were evaluated statistically. With increased nitrogen and phosphorus use, there was an increase in algae but a decrease in sensitive, Group III macroinvertebrates.
STEP 6: Drawing a Conclusion
From this study of 45 test sites, Amanda found evidence that the practice of treating lawns near a stream has an effect on the biodiversity and health of the stream. The healthiest streams result when chemicals are not applied to lawn and field areas. However, disproving the hypothesis, slow-release synthetic, inorganic compounds affect a stream less than organic fertilizers. Further study of the area that would include determining the concentration of chemicals added to lawns would be important to continue evaluating the given hypothesis.
Comparing the study of lawn additives to agricultural areas would be interesting to see the effect of inorganic and organic chemicals on large croplands. A brochure for the community properties would be advantageous to the area residents who continue to use lawn chemicals.
STEP 7: Create a Presentation
To present her final project, Amanda developed a detailed written report explaining her hypothesis, her research, the data collected, and her final conclusion. In addition, she wrote a one-page abstract that briefly and accurately explained the project and the data obtained, along with a brief conclusion.
She created a display with a folding board, where she hung her abstract, a map of the area studied, photographs of each site, her data sheet, and a bar graph showing the variations in stream biodiversity at different sites. She also displayed her journal containing notes from the field.