Bugs, Brook Trout, and Water Quality: How Are They Connected?

Transcription

1 Subject/ target grade: Middle School (8 th grade) Earth Science Bugs, Brook Trout, and Water Quality: How Are They Connected? Duration: Four 50 minute periods Setting: Classroom and computer lab Materials and Equipment Needed: Per class Computers with Microsoft PowerPoint and a Projector Per student Worksheet Packet: Michigan Environmental Education Curriculum Water Quality Lesson 7 : How Healthy Is this Stream? Student Background Reading: Water Quality in Michigan Stream photos comparing the 4 streams Learning Objectives: List characteristics of good water quality. Define benthic macroinvertebrates and explain their role in the aquatic food chain. Classify common stream macroinvertebrates into pollutionsensitive, somewhat pollution sensitive, and pollution tolerant. Explain why macroinvertebrates are used as bioindicators of stream health. Interpret basic water quality, bioassessment, and stream habitat data to make management recommendations. Lesson Overview: Students are introduced to the physical, chemical, and biological characteristics of an ecologically healthy stream and to the procedures used by scientists and aquatic biologists for assessing the health of a stream. Students use their new knowledge to select the best stream in which to plant young brook trout after evaluating the presence of pollution sensitive bioindicators, the availability of appropriate habitat, and the presence of good water quality from data provided for four Michigan streams. Lesson Core The Guiding Question: How can we measure the health of a stream? Safety precautions: None. Advanced Preparation: Prepare all worksheet packages for each student. Prepare a short presentation to describe and define the steps of the scientific method. Background Information for Teachers: See Background Information (Student Reading) below. Important Terms: active stewardship phosphates algal blooms dead zone non point source of pollution Watershed Connections Bugs, Brook Trout, and Water Quality Lesson 5 1

2 Michigan Content Expectations: E1.1A. Generate new questions that can be investigated in the laboratory or field. E1.2K. Analyze how science and society interact from a historical, political, economic, or social perspective. E4.1C. Explain how water quality in both groundwater and surface systems is impacted by land use decisions. B1.2F. Critique solutions to problems, given criteria and scientific constraints. B3.2C. Draw the flow of energy through an ecosystem. Predict changes in the food web when one or more organisms are removed. What streams are good habitats for Brook Trout? What does a poor quality stream look like? Can you think of any examples of either type in your neighborhood? Why is it important to keep streams healthy? Who is responsible for maintaining stream health? What can be done to improve the health of our streams? How do streams impact the health of a watershed? Could an unhealthy stream affect the quality of your drinking water? aquatic ecosystem measures of stream health cold water stream warm water stream stream habitat pool riffle run benthic macroinvertebrate sediment bioindicators shredders collectors grazers predators perennial water quality parameters ph turbidity temperature dissolved oxygen Engage: What do Brook Trout need to survive? Building on prior knowledge: How can we tell if a stream is healthy? What does a healthy stream look like? Pre teaching: See Background Information on following page. Assign students to read as homework the night before the lesson. Have students define the underlined words in the reading. Explore: Day 1 Discuss student answers and impressions gained during the background reading. Have students read their definitions of the underlined words in the reading. Answer any questions the students have over the material. What do fish in Michigan streams and rivers need to live? A habitat is the living and non living environment of an organism or population of organisms that provides the essentials for life. Animals require food, water, shelter/cover, oxygen, and space in the proper arrangement. Different species of organisms have different habitat needs and can survive under widely differing environmental conditions. Some organisms are very sensitive to the Watershed Connections Bugs, Brook Trout, and Water Quality Lesson 5 2

3 presence of pollution and have very narrow habitat requirements, while others can tolerate a wide variety of conditions, including pollution. Coldwater fish species (e.g., brook trout) require high levels of dissolved oxygen, year round stream flows, clear water (no turbidity), and a hard, gravel stream bottom. Warm water fish species (e.g., bass, crappie) can tolerate low levels of dissolved oxygen, variable stream flows, muddy water (high turbidity), and a soft, silty stream bottom. Compare Bocco Creek and Linden Creek. Display the PowerPoint slide of the two creeks side by side. Which appears to have habitat better suited for a cold water fish species, such as a native brook trout or introduced salmon, or a warm water fish species, such as native smallmouth bass or introduced carp? Have students make a drawing of each stream in their science journal and compare the characteristics of each stream. Bocco Creek has a greater diversity of vegetation trees, shrubs, and grasses along the stream banks, providing more shade and cooler water temperatures. There are rocks on the stream bottom, curves in the channel, and the water is clear (can see bottom). Bocco Creek is a good stream for cold water fish. Linden Creek has only grass and bare rocks along its human made, straightened channel. There are no overhanging trees or shrubs to shade and cool the water, and therefore less dissolved oxygen is available. It is difficult to see the channel bottom, indicating the possibility of suspended sediment or turbid water. Linden Creek appears more suitable for warm water fish. How can we determine if a stream is healthy? How does a doctor determine whether you are healthy or not? When you visit the doctor for a checkup, the doctor gathers background information by asking questions, performs a series of tests (pulse rate, blood pressure, etc.) that help to assess your health, and compares your measurements to typical conditions of healthy people. Measurements out of the normal range will lead to more advanced tests. Stream ecologists and water resource specialists follow the same procedure when investigating the health of a stream. A stream monitoring investigation includes evaluating physical, chemical (water quality), biological, and habitat characteristics of a stream. A water chemist, fisheries biologist, hydrologist, aquatic biologist, and stream ecologist may all be involved in assessing the health of a stream. How are bioindicators used to evaluate the health of a stream? Display the Aquatic Food Chain overhead transparency and discuss the role of macroinvertebrates in the food chain and their use as bioindicators. What is a bioindicator? [Any living organism whose presence indicates the quality of the environment. For example, canaries were used in early coal mines to indicate air quality. Because the canary was more sensitive to high levels of methane and carbon monoxide, if the canary died, the miners knew to exit the mine immediately.] What are benthic macroinvertebrates? [Benthic means bottom dwelling, and macroinvertebrate refers to an organism that does not have a backbone and is large enough to be seen by the unaided eye.] Watershed Connections Bugs, Brook Trout, and Water Quality Lesson 5 3

4 Why are benthic macroinvertebrates useful bioindicators? [They are not mobile, are fairly easy to identify, have short life cycles (less than a year), and do not require expensive equipment to collect.] Demonstrate how to use each of the data forms using the overhead transparencies. Assign student groups to evaluate all four streams, or assign one stream to each group, if time is limited. How does water quality influence the types of benthic macroinvertebrates that can live in a stream? [Different types of macroinvertebrates have different tolerances or requirements for temperature, dissolved oxygen, ph, turbidity, and habitat.] Review the three categories of macroinvertebrate groups according to their pollution tolerances: Day 2 Pollution sensitive: stonefly nymphs, caddisfly larvae, (most) mayfly nymphs, hellgrammites(dobsonflies), gilled snails, and water pennies Somewhat pollution sensitive: dragonfly and damselfly nymphs, crane fly larvae, beetle adults and larvae Pollution tolerant: aquatic worms, midge fly larva, pouch snail, true bugs, true flies, water striders, backswimmers, etc. The Challenge: In which stream should the Brook Trout be planted? Organize students into small groups and distribute Where Should the Brook Trout Be Planted? student packets. Tell students that they will be fisheries biologists with the Michigan Department of Natural Resources. Their job is to determine which stream (Clinton River, Coles Creek, Gilkey Creek, and Au Sable River) is suited for planting small brook trout fish fry raised in Michigan s fish hatcheries. Students will: Review the brook trout s water quality and habitat requirements and record in the Stream Assessment Data Table. Conduct a biological assessment by classifying and counting the macroinvertebrates for each stream, tallying the score(s) on the Biological Assessment Data Form, and recording the final score(s) in the Stream Assessment Data Table. Review the water quality data (dissolved oxygen, temperature, turbidity, ph) for each stream and record in the Stream Assessment Data Table. Conduct a habitat assessment for each stream using the page with photographs of the four streams and the Stream Habitat Assessment Form. The photos may be printed from the MEECS Water Quality CD ROM for each group, or projected in color for the entire class to use at the same time. Record the scores for each stream on the Stream Assessment Data Table. Compare the data and select the stream that will provide the best habitat for the young brook trout. Give three reasons for the stream selected. Explain: Have students prepare a short (5 slides minimum) MS Powerpoint presentation to share their results with the class. See the MS Powerpoint Presentations and gradic rubric. Discuss students findings and recommendations. Watershed Connections Bugs, Brook Trout, and Water Quality Lesson 5 4

5 Could they have determined the best stream by sight alone? [No, a stream ecologist needs to assess water quality, habitat, physical characteristics, and bioindicators in order to have a complete understanding of a stream s health. ] Elaboration: Do the online web module Stream Monitoring developed by Michigan Technological University ( meec_index.htm) where students compare the characteristics of three streams to determine which is healthiest. Alternatively, have students do the web module Aquatic Ecosystems: Rivers and Streams to see how streams are formed and investigate what habitat characteristics are essential for Lake Sturgeon survival during their juvenile years in Michigan streams. Have students Design a Macroinvertebrate in class or for homework. Students select a macroinvertebrate to create using clay, toothpicks, yarn, etc., showing as much detail as possible. Students present their model to the class, describing its distinguishing characteristics and identifying whether it is sensitive, somewhat sensitive, or tolerant to pollution. Alternatively, students may exchange their macroinvertebrate models and see if another student can determine its correct identity. See Additional Resources and Macroinvertebrate Identification Web sites. Evaluate: Students will be graded on both their participation and Powerpoint presentation using the following rubric for a total of 45 points. Lesson Closure: Who monitors stream health? Why is it important? Why are stream macroinvertebrates useful? Lesson Extension Additional Resources: Michigan Environmental Education Curriculum, Water Quality module, Stream Monitoring. Aquatic Entomology is amazingly beautiful. The illustrations alone make it worth the money. This book is an invaluable source of high quality images. The pictorial keys are also very helpful; they are very easy to follow and make it almost a simplistic task for a lay person to identify aquatic insects down to the family level. Some of these keys are a little outdated since publication of the book, but they are still helpful. McCafferty, W.P. (1998). Sudbury, MA: Jones & Barlett Publishers. A Guide to Common Freshwater Invertebrates of North America is an excellent guide to family level invertebrate identification, with wonderful pictures and excellent background information on the organisms. It contains the fundamentals of freshwater invertebrate biology, as well as general information about habitat, feeding, movement, breathing, life history, and stress tolerance, plus a Quick Guide for identification of each specific group. Voshell Jr., J. Reese. (2003). Blacksburg, VA: MacDonald and Woodward Publishing Co. Watershed Connections Bugs, Brook Trout, and Water Quality Lesson 5 5

6 Aquatic Invertebrates and Water Quality is a 7 minute introduction to the use of aquatic invertebrates to assess water quality. Contains great close up photography of macroinvertebrates under the microscope to observe characteristics and behavior. Missoula Conservation District. (1989). Missoula, MT: Missoula Conservation District. To order: tips that can help people reduce nonpoint source pollution in watersheds across the country. Both the video and transcript may be viewed online. Oregon State University Extension. (n.d.). Corvallis, OR: Oregon State University Extension.To order: os/. S.O.S. for America s Streams A Guide to Water Quality Monitoring is a 28 minute video demonstrating biological stream monitoring methods, macroinvertebrate identification techniques, and how to adopt a stream. The Izaak Walton League of America. (n.d.). Blacksburg, VA: McDonald and Woodward Publishing. To order: Tel: (800) We All Live Downstream is a 29 minute video that examines urban and rural runoff and the problems it creates for America s surface and groundwater supplies. It also offers Watershed Connections Bugs, Brook Trout, and Water Quality Lesson 5 6

7 Michigan s 35,000 miles of rivers and streams make the state a water wonderland and a fish, wildlife, and recreation paradise. This tremendous resource contributes significantly to our economy and quality of life, largely due to national and state environmental protection laws, careful enforcement by government agencies, and active stewardship of our water resources by industry, business, agriculture, forestry, watershed councils and other organizations, and concerned citizens of Michigan. Michigan s Rivers: A Dirty Past and A Promising Future Michigan s water wonderland wasn t always so wonderful. There was a time when there were no environmental protection laws. In the early 1900s, unregulated industrial and municipal discharges regularly spewed waste oil, chemicals, and untreated sewage from cities and towns directly into rivers and the Great Lakes. Apathy about the oil and sewage matted rivers changed in 1948 when angry sportsmen with the Michigan United Conservation Clubs outraged by the deaths of thousands of ducks on the Detroit River, dumped truckloads of oil soaked duck carcasses on the sidewalk of the State Capitol in Lansing in protest. Water Quality in Michigan Background Information (Student Reading) decomposition process, resulting in fish kills and dead zones (areas without dissolved oxygen which can no longer support fish and other aquatic organisms) in rivers and lakes. In addition, some rivers were so polluted that they caught fire. The Cuyahoga River near Cleveland, Ohio caught fire ten times over a hundred year period from 1868 to The Rouge River in Detroit also gained unwanted national attention in the late 1960s when its polluted surface caught fire. New Laws Are Passed A ban on the sale of high phosphate household laundry detergents was passed in Michigan in The 1987 amendments (Section 319) to the federal Clean Water Act required states to develop programs to control nonpoint sources of pollution from farms, urban and residential areas that were continuing to foul the nation s and Michigan s streams, rivers, and lakes. While the condition of our waterways has improved, many are still being polluted by nonpoint sources of pollution, such as storm water runoff, combined sewer overflows, fertilizer and pesticide laden agricultural and lawn runoff, air pollutants that fall into the water, motor oil swept into storm drains from parking lots during rainstorms, and erosion from stream banks where soil holding shrubs and trees have been removed. Many other Michigan rivers were choked with algae in the 1960 s due to discharges high in phosphates from household laundry detergents. Phosphates come from detergents, wastewater treatment plants or septic systems, fertilizer runoff from golf courses, lawns, and farming areas. While phosphorus is an important nutrient used in fertilizers to promote plant growth, the discharge of large amounts of phosphates had been shown to cause algal blooms. Then, when the algae died, it consumed most or all of the dissolved oxygen during the Land use decisions made by hundreds of townships, counties, and cities throughout Michigan have the potential to positively or negatively impact the future health of Michigan s rivers, streams, and ultimately the Great Lakes. For example, each decision to build a new minimall, new big box store, or new housing development that requires paving over a forest, farm field, or wetland reduces infiltration of rain and snow into the soil, reduces groundwater recharge, and increases polluted runoff to streams, rivers, and lakes when the natural vegetation buffer along waterways is removed. Watershed Connections Bugs, Brook Trout, and Water Quality Lesson 5 7

8 Working together to protect and restore the watersheds of Michigan s rivers, streams, and the Great Lakes is the most effective approach to improving water quality and enhancing aquatic ecosystems. Who Monitors Michigan s Water Quality? In Michigan, the Department of Environmental Quality (DEQ) has primary responsibility for monitoring the water quality of Michigan s streams, rivers, and lakes to track their ecological health. There is a great need for Michigan citizens to step in and assist with conducting more frequent water quality monitoring. This task is accomplished by many watershed councils, lake associations, school classes, and other citizen monitoring efforts throughout the state. The U.S. Geological Survey, the USDA Natural Resources Conservation Service, and the U.S. Environmental Protection Agency also conduct limited water quality monitoring. How Can We Tell if a Stream Is Healthy? There are four basic measures of stream health: stream habitat quality, bioindicators, physical channel characteristics, and water quality. Fishery biologists commonly group streams according to whether they are cold water streams or warm water streams. Cold water streams are usually well shaded by mixed hardwood (e.g., maple, beech, oak) and conifer forests. Cold water streams can typically support sculpins and trout brook, cutthroat, rainbow and brown and/ or coho and Chinook salmon. Warm water streams typically flow through more open forests, but in many cases the natural streamside vegetation has been altered or removed by human development. Typical warm water fish species may include suckers, minnows, bass, sunfish, rock bass, yellow perch, bullhead, and catfish. Stream Habitat Stream habitat is the availability of food, water, shelter, oxygen, and space in the proper arrangement. A healthy cold water stream has: Year round (perennial) stream flow Mostly gravel channel bottom materials Clear water with little suspended sediment Diversity of native streamside (riparian) vegetation (trees, shrubs, grasses, flowering plants) Overhanging trees and shrubs that provide shelter, shade, cooler water temperatures, and a source of leaves to the stream ecosystem (leaves falling into streams is an essential source of plant material to the stream) Sinuous, curvy channel Diverse in stream habitats including pools, runs, and riffles. Pools are the deeper parts of the stream that form on bends, behind log jams, at plunge sites, etc. Riffles are stretches of stream with small ripples where rocks break the water s surface, adding oxygen. Runs or glides are lengths of stream where water runs with little variation with a smooth, unbroken surface. The stream bottom is extremely important to the organisms that live there. The stream bottom is where benthic macroinvertebrates feed, live, and reproduce. These macroinvertebrates are an important source of food for fish that reproduce, lay their eggs, and rear their young in stream gravel. Too much sediment can impact fish and macroinvertebrate habitat by covering stream bottom gravels. Fine sediment suspended in the water makes the water turbid or cloudy and reduces the amount of sunlight shining through the water, limiting the ability of algae and aquatic plants to photosynthesize and produce dissolved oxygen. Watershed Connections Bugs, Brook Trout, and Water Quality Lesson 5 8

9 Channel Bottom Substrate Size Categories Substrate (channel bottom materials) Size (diameter) What does it feel like? Silt, clay < 2 mm feels smooth like flour Sand < 0.25 cm feels gritty Gravel Cobble Boulder < cm 5 25 cm > 25 cm A handful fits in your hands You can stand on; baseball size You have to climb over Bedrock > 25 cm Solid rock Bioindicators Benthic macroinvertebrates play a key role as bioindicators of stream health and water quality. Benthic means bottom dwelling, macro means large enough to be seen by the unaided eye, and invertebrate means without backbone. Benthic macroinvertebrates are good bioindicators of environmental quality for the following reasons: Unlike fish that can swim away from pollution, benthic macroinvertebrates are relatively sedentary. Macroinvertebrates can be divided into three groups: pollution sensitive, somewhat pollution sensitive, and pollution tolerant. Macroinvertebrates often have short life cycles, and some even have several generations in one year. They are easy to collect and identify to broad groups, e.g., order or family. Some examples of benthic macroinvertebrate bioindicators are: Pollution sensitive: stonefly nymphs, caddisfly larvae, (most) mayfly nymphs, hellgrammites (dobsonflies), gilled snails, and water penny. Somewhat pollution sensitive: dragonfly and damselfly nymphs, crane fly larvae, beetle adults and larvae. Pollution tolerant: aquatic worms, midge fly larva, pouch snail, true bugs, true flies, water striders, backswimmers, etc. In addition to being good indicators of stream health, benthic macroinvertebrates are a critical part of the stream food chain and the stream ecosystem. These macroinvertebrates are essential to the flow of energy and nutrients in the stream. They can be categorized by their feeding groups, i.e., the type of food they eat and the manner in which they obtain their food: Shredders (eat leaves falling into the stream) Collectors (either by filtering or collecting from the stream bottom) Grazers (eat algae off rocks and wood) Predators (eat other macroinvertebrates and small fish) Physical Characteristics The most important physical stream characteristic is having year round or perennial stream flow to support an aquatic ecosystem. Other physical characteristics include volume and velocity of flow. Water Quality The most important water quality parameters to measure are temperature, ph, turbidity, and dissolved oxygen. Temperature determines the amount of dissolved oxygen the water can hold. Cooler water temperatures with more dissolved oxygen support cold water fish species whereas warmer water with less oxygen supports warm water fish species, (e.g., bluegill, brown trout, and largemouth bass). ph is a measure of acidity and ranges from 0 14, with 7.0 neutral. Turbidity is a measure of the cloudiness in the water caused by Watershed Connections Bugs, Brook Trout, and Water Quality Lesson 5 9

10 suspended sediment or high concentrations of microscopic algae due to excess nutrients in the water. Sediment buries fish eggs and macroinvertebrates, damages gills, and interferes with the ability of fish to find food. Dissolved oxygen (DO) is essential for aquatic organisms. Lack of oxygen in the water can cause many macroinvertebrates and fish to die. Watershed Connections Bugs, Brook Trout, and Water Quality Lesson 5 10

11 Bugs, Brook Trout, and Water Quality: Stream Habitat Photos Watershed Connections Bugs, Brook Trout, and Water Quality Lesson 5 2

12 Bugs, Brook Trout, and Water Quality: MS Powerpoint Presentation Requirements: 1. Introduction: Why stream monitoring is important What stream monitoring can tell us 2. Habitat requirements for Brook Trout 3. Methods: Describe what you measured and how you did it. 4. Results: Describe your results in one paragraph with reference to tables and figures. Data: Include at least one table of the data you collected. Figure: Include at least one graph of the data you collected. 5. Conclusions: Interpret your results and provide a recommendation as to where the Brook Trout should be stocked. Explain why the brook trout should be planted in which streams. There is at least one slide describing why stream monitoring is important. At least one slide describes the habitat requirements for Brook Trout. At least one slide explains the measurements you collected. Results are explained in text with reference to tables and figures. The presentation contains a table of the data you collected in proper format. The presentation contains at least one graph in the proper format. The presentation describes conclusions that can be drawn from your data. Group work was equal when collecting data and preparing the presentation. Group members were positive and mature when working together. Total of 45 points Watershed Connections Bugs, Brook Trout, and Water Quality Lesson 5 3