What Factors Affect Macroinvertebrate Life in Big Darby Creek?

Picture of Big Darby Creek

Image courtesy Ohio Dept. of Natural Resources

To identify trends and make predictions about the possible influence of climatic factors and vegetative growth on macroinvertebrates
Grade Level: 6 – 8
Estimated Time for Completing Activity: 90 minutes
Learning Outcomes:
  • Students will access scientific data from an internet database (Live Access Server)
  • Students will generate and interpret line graphs from three different sets of data
  • Students will compare graphs to identify correlations among factors investigated
  • Students will make a prediction based on patterns in the data
  • Overview of macroinvertebrates and how they can help determine the health of a given stream
  • Prior experience using latitude and longitude to locate a geographical position
  • Prior experience with looking for patterns and trends in line graphs
  • Prior experience with using graphical data to support a prediction or conclusion
  • Computer with Internet access
AP Environmental Science Topics
Lesson Links:

The Darby Creek watershed encompasses an area of approximately 550 square miles in central Ohio. The Big and Little Darby Creeks are well known for their vast diversity and abundance of aquatic and terrestrial plants and animals. They are home to eighty-six species of fish, five of which are endangered. Forty-one species of freshwater mollusks live in these waters, eight of which are on the Ohio endangered list.

To monitor the health of any creek, students can be trained in stream quality monitoring, which involves examining the presence of macroinvertebrates in a stream. Macroinvertebrates are animals without a backbone that are larger than a half millimeter such as crayfish, snails and worms. There are twenty common macroinvertebrates, divided into three taxa. Taxa are categories of living organisms following taxonomy (phylum, class, order, family, genus, species). Students can learn to identify each of the twenty types and their respective taxa. The number of species present from each taxa converts to a Cumulative Index Value (CIV) from 0 – 22. Any value above 22 indicates excellent water quality.

When looking at the health of a naturally occurring water feature, such as a stream or creek, the abundance of organisms is the focus of study. It is also important to consider the health of individual populations of macro invertebrates in a particular area. In order to do this several factors have to be taken into account. One method involves monitoring the stages of metamorphism that particular organisms undergo. If certain stages are not present in the life cycle of a particular organism, this could indicate poor health. Once the adult stage is reached, their final task before death is to reproduce. Poor organism health might not allow for the adult stage to be reached and result in declining populations. Another method of determining macro invertebrate health is to look at the trends in numbers. A sudden decline in a population could be a sign of health decline. One other method used to determine health of macro invertebrate populations is tolerance to outside materials. A healthy organism will have the ability to resist a certain amount of toxins that could harm them and surrounding organisms. However, if there is deterioration of health, the ability to resist these toxins will deteriorate as well.

Historically, the annual September sampling at Big Darby Creek has yielded scores in the excellent range. There have been significant fluctuations in the CIV values, including a downward trend over time. This activity is designed to study the factors that may affect the creek.


1. As a class or in small groups, discuss how to identify macroinvertebrates, their classification and their characteristics and needs as living things.

2. Answer Questions 1 – 5 below. Discuss your answers, including precipitation, air temperature and vegetation as possible influencing factors. Record discussion points in your notes.

3. Review the Big Darby Creek CIV historical data chart (Lesson Link) to identify patterns and trends.

4. Explore the Live Access Server, finding any location, dates and any parameter to learn how to make a time series (line graph) of data. Note: You may want to attempt to repeat the same graph as a class, checking your work to confirm correct generation of the graph.

5. Select one parameter at a time for the time period 2000 through 2005, and generate a time series line graph for precipitation, near surface air temperature and NDVI at the Big Darby Creek latitude and longitude (39.54 N, 83.12 W).

6. After generating each graph, compare your generated graph to the historical data chart, trying to identify any correlation of both data sets.

7. Organize the graphs to make a CIV trend prediction (higher, lower, same level) corresponding to current weather data. Write a report about your prediction.


1. Does climate affect human behavior?

2. What factors influence macro invertebrate life in Big Darby Creek the most?

3. Could some of the factors that affect macro invertebrates also affect humans in a similar way?

4. What other factors could you speculate affect macro invertebrates but may not directly affect humans?

5. What evidence could you gather to verify your claim from question 4 above?


1. Compile recently collected data with historical information: Are your predictions supported by the evidence? Why or why not?

2. Find river or stream corridor changes from historical satellite images to identify possible urban growth contributions to declining CIV.

Lesson plan contributed by Alan Hans, Hilliard, Ohio

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