Water – An Essential Component of Wetlands (PCEC)
Participants will observe water in a wetland area and predict the water quality based on the organisms found. Tests will check dissolved oxygen, pH, temperature and light penetration of Cook’s Lake. From these tests, participants will analyze their predictions that were based on the organisms in Cook’s Lake. (Note: A number of prerequisites are needed. The PCEC educator will explain these when the activity is scheduled.)
5 and up
Indoor or outdoor classroom
Potlatch Conservation Education Center at Cook’s Lake, Casscoe
Education Program Coordinator, 870-241-3373
One to three hours
Suggested Number of Participants:
20 - 25
One adult supervisor per 10 students; outdoor activities, weather permitting.
- Observe the characteristics of the water environment.
- Observe, collect and identify aquatic organisms.
- Predict lake characteristics.
- Test for pH, dissolved oxygen, light penetration and water temperature in Cook’s Lake
- Analyze test results and compare them to predictions based on the organisms in the lake area.
Biochemical oxygen demand
*See glossary for definations
Five to 10 baby food jars
Magnifiers (dissecting scope if available)
“Pond Life” guide book
Two dip nets
Water: An Essential Component of Wetlands Worksheet – one copy per group
Water test kit
White pans or specimen pans
Wetlands are areas covered by water enough of the year that they support aquatic plant and animal life. Wetlands may range from a permanently flooded area to an area that is seasonally saturated. The area of Cook’s Lake is a wetland region where the soil is covered with water or waterlogged in different seasons.
- Prerequisites: Prior to arriving, participants should be exposed to the different types of freshwater biomes and learn the characteristics and importance of wetlands and freshwater biomes. Participants should be aware of the hazards of working with chemicals in the test kits and the dangers of working near Cook’s Lake. They should be able to follow simple reading directions and data collection directions.
- Participants should work in groups of four to six. The teacher should assign these groups prior to arriving at Cook’s Lake. This type of grouping will let each participant be leader, recorder, materials gatherer, reader and expediter.
- Provide each group with a copy of the participant worksheets (see attached). Instruct participants to observe the area around the lake. Record any plants, animals or nonliving factors observed in the area in chart I of the worksheet.
- Participants will use their dip nets and jars to collect as many different organisms as possible in 15 minutes. At the end of 15 minutes, they will place their specimens in the white specimen pans or dishpans so the group can observe them. Place the specimens in a shady place or cover lightly with a piece of paper to protect them from the sun and drying out. Be sure to keep them wet or moist.
- Using a pond life field guide, identify the specimens.
- Using chart II of the worksheet, participants will list or sketch the animals collected. As soon as all specimens have been identified, they will be returned to the lake. Caution participants not to harm them and return them to the same area where they were collected.
- Have participants predict the conditions found in Cook’s Lake using the questionnaire, chart and data tables in the worksheet. A printable copy is included at the end of the lesson.
- Show participants where to pick up the water test kit for the next exercise. Each person must be involved in conducting tests, recording results and analyzing them. Conduct tests for water and air temperature, dissolved oxygen count and the pH of the stream or pond. Record the results on chart III in the participant worksheet. Use the predictions made earlier to compare the results. If time permits, take water samples from two different sections of the lake (example: close to shore and by the dock).
- Use table E and F of the worksheet to determine the amount of light penetration in the lake and the effects of dissolved minerals on fish population.
- Have students return all materials to the appropriate area and containers. Dispose of all samples containing chemicals in containers provided by the instructor.
Use this hypothetical situation: At the back of your campus, there is a lake that has carp, catfish and some insects. The temperature is about 22°C and the color is red to dark brown. In your opinion, is this a productive lake? Why or why not? Support your opinion with facts.
- After analyzing the experimental data gathered from Cook’s Lake, how accurate were the predictions?
- Is Cook’s Lake a productive, thriving lake? Why or why not?
Water: An Essential Component of Wetlands
My Predictions about Cook’s Lake
Biochemical oxygen demand (or biological oxygen demand) – amount of oxygen required by aerobic microorganisms to decompose the organic matter in a sample of water, such as that polluted by sewage; measures water pollution
Dissolved oxygen – amount of oxygen in fresh water such as a stream or freshwater lake
Emergent plant – a plant rooted in shallow water with much of the stem and most of the leaves above water
Euphotic zone – zone of water in a sea or lake where sufficient light penetrates to allow photosynthesis; zone depth is limited by water clarity
Eutrophic lakes –rich in plant nutrients and thus produces high numbers of phytoplankton (suspended algae) which often cloud the water so that poor Secchi disk readings (average about 8 feet) are expected; also produces high numbers of zooplankton and minnows and other small fish that feed on the zooplankton
Limnetic zone – open water of a pond or lake supporting plankton growth; shallower in turbid water than in clear and a more prominent feature of lakes than ponds; dominated by floating microorganisms called plankton and actively swimming animals called nekton
Littoral zone – portion of a fresh water body extending from the shoreline outward to the limit of occupancy of rooted plants; also the strip of land along the shoreline between the high and low water levels
Oligotrophic lakes – possess low nutrient concentrations and low plant growth; phytoplankton, zooplankton, attached algae, aquatic weeds, bacteria and fish are small populations
pH scale – measure of a liquid’s or solid’s alkalinity, represented on a scale of 0 to 14 with 7 being a neutral state, 0 the most acidic and 14 the most alkaline
Submerged plant – grow underwater, rooted in the bottom and have stems that grow toward the surface