Investigating Aquatic Ecosystems: Macroinvertebrates and Water Quality

Becky Fink
Cloquet High School
Cloquet, Mn
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Summary

In this field lab, students investigate three aquatic ecosystems to determine the relative pollution index and the water quality of each ecosystem. Students collect and analyze the benthic organisms found in each system. Students conduct a water quality assessment on each system. Students investigate a pond and a stream first hand and are given data for a bog.
After collecting data, students analyze the ecosystem. Students work in groups and compare their data to the other groups in the class.


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Learning Goals

Learning Goals
1. Precise and accurate collection of water quality data.
2. Analysis of water quality data
3. Specimen collection and identification of benthic organisms.
4. Analysis of benthic organisms found to find a pollution index number.

Key Concepts
1. Precise and accurate collection of data.
2. Describe the water quality using chemical means.
3. Access pollution level in each system using benthic organisms as indicators.

Vocabulary Words:
benthic organism
dissolved oxygen content
carbon dioxide content
hardness
pH
nitrates/nitrites
nitrite content/nitrate content
turbidity

Context for Use

This activity is designed for a high school Biology classroom.
Class size: 30 students to 1 instructor
Time Frame: 10 days --toward the beginning of the school year (October)
Special equipment:
Kick nets
Ice cream pail with lids
Water chemistry kits(DO, CO2, Nitrates, Hardness, pH)
Thermometers
Secchi disks or turbidity tubes
Waders and rubber boots
For Critter Hunt: dissecting microscopes, forceps, eye droppers, petri dishes, dissecting trays
Lab report packet- pre-made data tables for each ecosystem. Be sure to include water temperature, turbidity, rate of flow, chemical test results and weather on collection day.

Subject: Environmental Science:Water Quality and Quantity
Resource Type: Activities:Classroom Activity, Field Activity, Lab Activity
Special Interest: Field-Based Teaching and Learning
Grade Level: Middle (6-8), High School (9-12)
Theme: Teach the Earth:Enhancing your Teaching:Teaching in the Field, Teach the Earth:Course Topics:Environmental Science, Teach the Earth:Teaching Topics:Water

Description and Teaching Materials

Day 1: Lecture and prelab
Describe the purpose for the lab. Introduce benthic organisms and how they relate to a pollution index.
Introduce and demonstrate invertebrate collection methods. Introduce chemical test and procedures. Explain what the chemical tests mean in determining water quality. Hand out lab report packets. Break students into groups of 4 and give them a few minutes to decide who is performing which tasks.

Day 2: Pond Collection
Take students to a pond and let them collect data and invertebrates.

Day 3: Critters Hunt
Indoor lab--Students will take what they collected yesterday and identify the organisms and classify them into "pollution groups". Collect class data. Determine a pollution index number from the class data.

Day 4: Class water chemistry data collection and assessment.
Each group reports their water chemistry data to the class so the data can be compiled. Water quality assessment is done from the class data, not group data.

Day 5: Analysis of the pond ecosystem and intro to the stream.
Review what the chemistry numbers mean for water quality and what the benthic organisms indicate about the health of the pond. Make a final analysis of the water quality and pollution level in the pond. Introduce the stream. Have students predict what their results of the stream analysis will be. Let students work in their groups to determine jobs. (I make them switch jobs).

Day 6: Stream collection
Take students to a stream and collect data and invertebrates.

Day 7: Critter Hunt
Indoor lab--Students will take what they collected yesterday and identify the organisms and classify them into "pollution groups". Collect class data. Determine a pollution index number from the class data.

Day 8: Class water chemistry data collection and assessment.
Each group reports their water chemistry data to class so the data can be compiled. Water quality assessment is done from the class data, not group data.

Day 9: Discuss stream ecosystem.
Review what the chemistry numbers mean for water quality and what the benthic organisms indicate about the health of the stream. Make a final analysis of the water quality and pollution level in the stream. Hand out bog data and have groups work on an assessment of this ecosystem.

Day 10: In class activity.
Compare the three aquatic ecosystems in terms of water quality and pollution levels. Make a final analysis. Turn in lab report packets. Macroinvertebrates and pollution (Acrobat (PDF) 221kB Aug13 08)

Teaching Notes and Tips

As with any water activity, I stress the importance of being safe. There is no horseplay (ie. no splashing, no pushing,etc). Students are immediately removed from this activity for inappropriate behavior. I ask students to bring extra clothes to school on field trip days as some of them will end up getting wet (from leaking waders or boots).

Assessment

Informal assessment: Group collected data accuracy and work ethic of the group. I have the students grade the rest of their group for effort and take that into account when assigning a lab grade.
Formal assessment: Lab report packet.

Standards

IV.B.2
IV.C.4
IV.F.1

References and Resources