Hands-on Activity Your River's Health

Learning Objectives

After this activity, students should be able to:

• Identify more than one species of macroinvertebrate.
• Understand that species diversity reflects healthy ecosystems.
• Calculate a diversity index.
• Recognize that engineers must consider environmental impacts when designing dams

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS: Next Generation Science Standards - Science

Common Core State Standards - Math

International Technology and Engineering Educators Association - Technology

State Standards

Materials List

For the field trip, each group needs:

• 1 pail or bucket
• 1 or 2 plastic water or soda bottles to scoop up invertebrates (cut off bottle tops)
• 1 dishwashing scrub brush with bristles
• waterproof galoshes to permit students to stand in river water to collect water

For classroom analysis, each group needs:

• 1 aluminum casserole tray
• 1 magnifying lens or microscope
• 1 pair of tweezers or another tool to move macroinvertebrates around
• Macroinvertebrate Stream Sampling Worksheet, one per person

Worksheets and Attachments

Pre-Req Knowledge

Be able to perform division using a calculator. It is helpful if students understand the meaning of "species."

Introduction/Motivation

Can you think of any problems the building of a dam might cause? Constructing a dam on a river is a gigantic change for that ecosystem, and the health of the river might be affected by such a big change.

How might engineers test the health of a river? One way is to study the macroinvertebrates in the river. Macroinvertebrates are bugs and insects that spend part or all of their life in streams. Which situation do you think represents a healthier river: one that has many different types of bugs, or one that only has one or two types? Having many different types of bugs is an indication that the ecosystem is balanced enough to support each of them.

Today we will test the health of a nearby river (or stream or irrigation ditch). We will collect macroinvertebrate specimens and count how many different kinds we find as a way to gauge the health of the stream. Engineers do this kind of testing before and after designing and creating a dam, as a way to make sure that that the dam has not damaged the health of the river.

Procedure

Before the Activity

• Arrange a field trip to a local river, stream or irrigation ditch. Or, if a field trip is not possible, collect water samples from a local body of water in advance for students to analyze in class.
• Gather materials and equipment. Make sure the pails and bottles are clean.
• Make copies of the Macroinvertebrate Stream Sampling Worksheet for use in the classroom after the field trip.

With the Students: In the Field

1. Divide the class into teams of three students each.
2. While standing by the side of the river, stream or ditch, point out example macroinvertebrates to students.
3. Have teams use the cut-off bottles as scoops to fill their pails with river water. To maximize the number of insects present in the water samples, direct students to scoop water near the bottom of the river.
4. Lift up a few medium-sized rocks from the river bottom and use the scrub brushes to scrape some algae and invertebrates off the rocks and into the pail.
5. Use the scoops to remove from the pails extra water that does not contain organisms to make room for the addition of water into the pail as more organisms are collected.
6. Take pails of river water back to the classroom for analysis.

   

With the Students: In the Classroom

1. Working in teams, pour some water from the pail into the aluminum tray.
2. Use the magnifying lens or microscope to view the organisms, and the tweezers to manipulate them.
3. Hand out the worksheets for students to complete, including calculating the sequential comparison index (SCI).
4. Conclude with a class discussion to review student results. Make a classroom chart on the board to review findings as they pertain to the Thirsty County scenario (see post-activity questions provided in the Assessment section.)

Vocabulary/Definitions

diversity: A variety of forms or things.

engineers: People who apply their understanding of science, mathematics and society to create things for the benefit of humanity.

macroinvertebrate: An invertebrate animal (one without a backbone) large enough to be seen without magnification. River macroinvertebrates are bugs and insects that spend part or all of their life in streams.

species: A class of individuals having some common characteristics or qualities; distinct sort or kind. Considered the basic category of biological classification, composed of related individuals that resemble one another and are able to breed among themselves. For this activity, different types of macroinvertebrates or bugs.

tally: A mark made to record a number or count, often consisting of four consecutive vertical lines with a diagonal line through them to indicate a group of five.

Assessment

Pre-Activity Assessment

Discussion/Brainstorming: As a class, have students engage in open discussion. Remind students that in brainstorming, no idea or suggestion is "silly." All ideas should be respectfully heard. Take an uncritical position, encourage wild ideas and discourage criticism of ideas. Have them raise their hands to respond. Record their ideas on the board. Ask the students:

• How do we know whether or not a river or stream is in good health?

Activity Embedded Assessment

Worksheet: Have students complete the Macroinvertebrate Stream Sampling Worksheet. Review their answers to gauge their mastery of the subject.

Post-Activity Assessment

Discussion Questions: As if these were results from Thirsty County, review the diversity and Birdseye River health findings of each group. Make a chart on the board of the different group findings. Discuss the results with students. Possible questions to ask:

• Did groups find different diversity (SCI) numbers? Why?
• How many different types of organisms did each group find?
• If our results were from the Birdseye River, what is its health?
• Do the results make sense? If the stream health was found to be poor, what are the possible causes of the poor health? (Possible Answers: Pollution from roads, towns or factories. Streams might run dry at some point in the year, killing some insects.)

Safety Issues

• At the river, watch students closely, especially if the water has any kind of current.
• Remind students to wash their hands after working with the river water.

Troubleshooting Tips

Make sure students clearly understand the sequential comparison index method; it can be confusing. Review the worksheet example so they fully grasp how to compute the SCI index.

Activity Extensions

Identify macroinvertebrate species by making copies of a macroinvertebrate key or looking at: http://people.virginia.edu/~sos-iwla/Stream-Study/StreamStudyHomePage/StreamStudy.HTML

Activity Scaling

• For lower grades, have students simply count the total number of organisms and the number of different species.
• For upper grades, have students use a macroinvertebrate guide to identify as many organisms as possible. One source: http://people.virginia.edu/~sos-iwla/Stream-Study/Key/MacroKeyIntro.HTML

Additional Multimedia Support

Use the online Aquatic Macroinvertbrate Identification Key: http://people.virginia.edu/~sos-iwla/Stream-Study/Key/MacroKeyIntro.HTML

While not as effective as actual field study of macroinvertebrates, the following online activity provides macroinvertebrate identification practice or a substitute activity if you do not have access to a stream or irrigation ditch: http://www.people.Virginia.EDU/~sos-iwla/Stream-Study/Samples/SampleIntro.HTML

References

Copyright

Contributors

Supporting Program

Acknowledgements

The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.