Aquatic Life. Concepts: Objectives: Activities in Lesson: Equipment: Vocabulary. Note to Teacher: Time: 1 hour, 50 minutes

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1 Aquatic Life Concepts: Aquatic organisms and terrestrial organisms have similar needs Aquatic ecosystems contain a wide variety of plant and animal species that depend on one other for survival. Objectives: The students will explore aquatic areas and niches. The students will examine characteristics and adaptations of aquatic life. The students will utilize research and resources to obtain information about aquatic life and habitats. Equipment: Viewing devices ph/do Test kits Magnifying glasses Food web cards/string Waterlogged cards Benthic Bedlam cards Paper Pencil ID charts & field guides Strainers/cereal bowls Note to Teacher: Aquatic habitats and organisms are not as readily visible as terrestrial creatures. Therefore, they are not as commonly investigated by young students. This lesson allows students to view many new creatures in a new environment. As the teacher, your main role will be to jumpstart and channel this exploration. Students will often be excited about being around the water but will need some direction about how to effectively explore an aquatic habitat. Modeling how to properly use the equipment and how to explore are often necessary before students will begin to explore on their own. Vocabulary Adaptation- any beneficial alteration in an organism resulting from natural selection by which the organism survives and multiplies in its environment. Aquatic- living or growing in water. Benthic- relating to or characteristic of the bottom of a sea, lake, or deep river, or the animals and plants that live there. Dissolved Oxygen (DO)- Oxygen that is freely available in water to sustain the lives of fish and other aquatic organisms. Facultative- able to live or take place under a range of external conditions Food Web- a series of organisms interrelated in their feeding habits, the smallest being fed upon by a larger one, which in turn feeds yet a larger one. Macroinvertebrate- an animal without a backbone that is large enough to be observed with the naked eye. Habitat- natural environment of an organism. Intolerant-unable to thrive or sur- Time: 1 hour, 50 minutes Activities in Lesson: Waterlogged (15 min) Benthic Bedlam (20 min) Water Quality Exploration (1 hour) Water Poems (15 min) vive in a particular environment Nymph- the young of an insect that undergoes incomplete metamorphosis. Niche- the position and function of a particular species or population in an ecological community. Parts per Million (ppm)- a measure of concentration ph (potential for Hydrogen)- measure of the acidity or basicity (alkalinity) of a material when dissolved in water. Terrestrial- growing or living on land. Tolerant-able to put up with harsh conditions or treatment Water Quality- the chemical, physical, and biological characteristics of water with respect to its suitability for a particular use. 13

2 Aquatic Life Waterlogged - (15 min) (adapted from Project Wet) Materials: Waterlogged Cards 1. Begin by asking the students: How important it is to have good, healthy water? Where is water found on the earth? (oceans, rivers, lakes, ground water, glaciers & polar ice caps, inland seas and salt lakes, atmosphere) How much of this water do animals and humans have to drink? 2. This activity will demonstrate the amount of water available for humans and other animals on the planet. Divide students into two groups. Lay down a rope or make a line in the dirt that is 20 feet long for each group. Explain to the students that the rope represents all of the water in the world; one end of the rope represents 0% percent, and the other end represents 100%. 3. Pass out a set of cards to each group of students. Each set of cards consists of seven different areas where water is found on earth. Each group should try to determine the percentage of water each type represents. Remind them that the total must equal 100%. Have them lay down the area of water on the line they believe represents the correct percentage they have determined for that area of water. For example, if they guess that oceans make up 75% of all the water, they would go to the place that represents approximately 75% of the line and place the ocean card on the ground. Variation: You can choose to hand out the percentage cards before you hand out the areas where water is found cards if you want your students to work with percentages and decimals or you can pass out the measurement cards if you want your students to practice measuring Benthic Bedlam (20 min) (adapted from Project Wet) Materials: Macroinvertebrate cards (use cards on next page). 1. Begin by asking the students: What is living in the water? What makes for a healthy water ecosystem? What happens if these conditions are not met? For what clues could you look to determine the health of a water ecosystem? Are there signs of human practices nearby? Introduce the concept of environmental stressors (agricultural runoff, sedimentation, etc.) and ask the students: How might an environmental stressors affect these organisms? Will all organisms be affected in the same way? 2. Introduce what macro invertebrates are and show several pictures. Tell the students that one way to monitor the quality of water is to sample the population of macro invertebrates. Explain that they are going to do an activity that simulates the changes in water quality once environmental stressors are introduced. 3. Define boundaries of the game then choose a student to be an environmental stressor. Divide the rest of the class into 7 groups. Each group represents one type of macro invertebrate species. Each species has a specific tolerance level: intolerant, facultative, and tolerant. Intolerant means the species cannot tolerate pollution; facultative means the species can tolerate some types of pollution; and tolerant means the species can tolerate pollution well. Next, distribute identification labels to all group members. You can have the students put the labels in their pockets, or attach them with a clothespin to their backs. Inform the students that certain macro invertebrates have hindrances to cross the field. These symbolize sensitive organisms intolerances to pollutants. 4. To begin the game, the macro invertebrates will line up at one end of the playing field. The stressor will be midfield. When a round starts, macro invertebrates move toward the opposite end of the field and the stressor tries to tag them. To survive, the macro invertebrate must reach the opposite end of the field without being tagged by the stressor. The stressor can tag any macro invertebrate, but will find it easier to catch those with hindered movements. Once tagged by the stressor, those macro invertebrates must go to the side and trade in their identification labels to portray the more tolerant species (I.e. rat-tailed maggot, midge larva). 14

3 Aquatic Life Tagged players who are already in a tolerant species group do not trade in their labels. The round will end when all of the macro invertebrates have either been tagged or have reached the opposite end of the playing field. Record the number of members in each species for each round played. 5. Play two or three more rounds with all tagged players rejoining the macro invertebrates who successfully survived the previous round. Because some players will have traded in their identification labels, there will be a larger number of tolerant species in each successive round. 6. Once a few rounds have been played, ask the students how the environmental stressor is affecting the health of the stream environment. What could we do to get rid of the stressor? (clean up the stream) Play a few more rounds this time hindering the stressor in some way, or getting rid of the stressor completely. Discuss the health of the stream now compared with the beginning of the game. 7. Discuss the outcome with the students. Emphasize the changes in the distribution of organisms among the groups, and have students compare population sizes of groups at the beginning and end of the game. Discuss reasons for the changes. Compare the stream environment at the beginning of the game to the environment at the end of the game. Review that some organisms are more tolerant to pollution than others. Discuss what can be done to reduce environmental stressors, and how that will affect the health of the stream. Water Quality Exploration (60 min) Materials: pencils, DO/pH kits, thermometers, strainers, buckets or tubs, magnifying glasses, identification sheets/guides. Explain to the students that they are going to become limnologists, people who study fresh water. As limnologists they are going to give the water a check-up to see how healthy it is. 1. Begin by asking students: Where do we get the water we use in Indiana? How much water is there in each area you named? (recall what they learned from the Waterlogged activity) Why is it important to have healthy water to drink? Are there living things other than humans that need healthy water? How can we tell if water is healthy? (chemical testing and a biological indexing that include indicator species can determine the health of a body of water.) 2. Explain to the students that they will be examining different aspects of an aquatic environment in order to determine its health. There are many pieces of information that can be gathered to determine the health of a body of water. Time plays a big part in determining what can be reasonably accomplished. It will help to divide the students into groups and assign a test to each. All students should participate in the Biotic Index collection. Before beginning any of the tests, allow students the opportunity to discuss what they think they will find. You will need to explain some terms and concepts before they are able to create a hypothesis, such as a riparian zone and turbidity. 3. To take the surface water temperature, place the thermometer a few inches under water and wait for two minutes to get as accurate a reading as possible. Record in degrees Celsius and Fahrenheit. To take the temperature of the water at or near the bottom of the body of water, tightly tie the thermometer to an anchor. Insure that the rope being used to lower the anchor is tightly tied to the anchor, as well. Lower the thermometer to the bottom of the body of water, or as low as it can safely go. Wait two minutes and record the temperature in degrees Celsius and Fahrenheit. Now ask the students: Why do you think there is, or is not, a difference between the surface and bottom temperature? What adaptations do you think aquatic organisms may need to make based on where they live in regard to temperature? 4. Explain what turbidity is and that suspended solids can be clay, silt, plankton, industrial waste, or sewage. Turbidity can affect the color 15

4 Aquatic Life of the water. When water is cloudy, the amount of aquatic organisms that can live in it will decrease. Now ask the students: If the water is cloudy, will the amount of aquatic organisms be affected? (yes, the amount will typically decrease) How can suspended solids affect the streams health? (increase turbidity) 5. Chemical testing can be introduced as a way to find things out about the water that we cannot detect with our own senses. Students are often excited by the idea of using chemicals and are eager to participate in the process. The chemical tests your students collect are Dissolved Oxygen levels (DO) and the water s ph levels. Explain the concepts of DO and ph before beginning this section. Begin by asking the students: What do you think our results will be? What factors will have an effect on our results? Of what importance will our findings be? At Bradford Woods we use Lamotte DO2 testing kits. a) Fill the small vial to overflowing with sample water. b) Add two dissolved oxygen tablets and cap (water will overflow vial). Make sure no air bubbles are present in the sample. c) Mix until tablets are dissolved. d) Wait five minutes for full color development. e) Compare the color of the sample to the DO color chart. **Note: Indiana Water Quality Standards state that concentration should average at least 5 ppm.** Follow the direction in your kits for the ph test **Note: Indiana Water Quality Standards state that values should fall between 6.5 and 8.2.** Discuss with the students the importance of keeping the sample free of contaminants and of being as accurate as possible with testing. 6. The next part of stream health examination will be to make a collection of aquatic creatures in order to determine the level of harmful pollutants in the water. This technique is known as a Biotic Index. A biotic index is based on examining different aquatic creatures and knowing how well those different organisms tolerate pollution. This index divides benthic, bottom dwelling, macroinvertebrates, animals without backbones which can be seen with the naked eye, into three groups according to their ability to tolerate a polluted habitat. Identifying macro invertebrates, counting them, and noting their tolerance to pollution can give you a good idea of the overall health of a stream. Explain how we can use organisms as an index of pollution and have them take note of which critters they find and calculate the Pollution Tolerance Index Rating. The following are example sampling methods to increase your students chances of successfully locating macroinvertebrates. Sampling Methods: Leaf Pack- look for brown and decomposing leaves. Place your net or strainer downstream from the leaf pack, holding the handle perpendicular to the water, shake the leaves, quickly scooping up the net Tree Roots/Submerged Logs/Debris Snags - start downstream from an area and move upstream. Gently disturb the surface with the net, a stick, a foot, etc. while holding the net downstream so the dislodged material flows into it. Sediments- best used in areas of mostly sand and/or mud. The person holding the net stands downstream of the sampling area with the net resting on the bottom while another person begins upstream, kicking and disturbing sediments to a depth of two inches as they approach the netter. The netter sweeps the net upwards and holds the opening an inch or two above the surface, washing sediment out of the net. Hand out cereal bowls and strainers to the students. Make hand lenses and identification materials available in a central location. When the students in each group have the necessary equipment, they may begin their search in the designated area. Students should collect samples of as many different organisms as possible, trying to identify each. When their sampling and exploration is complete, collect the equipment and start discussing the findings. 16

5 Aquatic Life Now ask the students: What critters did you find? Where did you find the most? How does the stream rate on the Pollution Tolerance Index? What does that tell us about the water quality of this stream? 7. After water quality exploration has finished help your students make connections and draw conclusions. What have we been doing during this study? What were we trying to find out? Why is it important to study water quality? Why would we study water quality over a long period of time? What methods did we use to examine water quality? (physical, chemical, biological) Why did we use each of these methods? Why did we use several different methods to study the stream? Did your results match your expectations? What do our results tell us? How healthy is this stream? What factors may have contributed to our results? What are some things we can do that could improve the water quality of this stream? Diamante: A poem shaped in the form of a diamond. It follows a pattern of the parts of speech. For example: noun adjective, adjective participle, participle, participle noun, noun, noun, noun participle, participle, participle adjective, adjective noun lake clear, large glistening, waving, moving animals, humans, eagles, trees growing, living, cleansing universal, connected life If there is time, have volunteers share their poems with the rest of the group. Water poems (15 minutes) Materials: paper, pencils. 1. Have students reflect on their experience investigating the aquatic habitat and its creatures and what they discovered about them. Students will now have the chance to put their thoughts into writing. They are going to write a poem about water or this aquatic ecosystem and what it means to them. It can be about how water relates to them, what healthy water means to them, or what the water might mean to the creatures that live in or around the water. The students may write a free form poem, a rhyming poem, or they may use one of the poem structures outlined below. Haiku: A Japanese poem consisting of 3 lines. The first line has five syllables, the second has seven, and the third has five. Rhyming is unnecessary. For example, The fish swam by me Nothing left in the shimmer My heart beats faster 17

6 Aquatic Life Evaluation: The students can correctly identify organisms The students demonstrate the process required to identify them The students will be able to explain the relationship of good water quality to humans and other creatures The students have engaged in their research using resources to obtain information. The students can name adaptations and the reason for the adaptations of at least 2 macroinvertebrates. Students have explored an aquatic niche. Students can explain the importance macroinvertebrates play in an aquatic niche. Notes: Keep in Mind: The riparian and aquatic environment is generally considered less accessible and more mysterious than terrestrial environments and are investigated less frequently by students. As the teacher, your main role will be to jumpstart and channel that exploration. Students will often be excited about being around the water but will need some direction about how to effectively explore an aquatic habitat. You may need to model how to properly use the equipment, gather the data, and to explore before students will begin to explore on their own. 18

7 Dragonfly Dragonflies are often seen in the summer months around the lake and the nymphs often found in aquatic life modules. The dragonfly is a specialized hunter, eating other insects such as mosquitoes and flies, which are captured in flight (9). Dragonflies have large compound eyes that nearly cover their heads (9). Dragonflies have 4 powerful wings that enable them to fly forward and backward (9). Amazing Fact - In bursts of speed a dragonfly can fly as fast as 1 mile a minute (8). Dragonflies have long legs, unsuitable for walking, which are used to hold insects captured in flight (9). You can tell a dragonfly from a damselfly because a dragonfly cannot fold their wings to the rear while at rest. Instead dragonflies extend their wings to the sides horizontally (9). Dragonflies mate while in flight. The male curls the tip of its abdomen to deposit a sperm packet in a chamber below its second abdominal segment. Then, while the male holds his mate by the neck, the female picks up the packet using the tip of her abdomen. Later the eggs are deposited in water (9). Lifecycle - Two to three weeks after the eggs have been laid, they hatch into nymphs or naiads. The nymphs are always eating other aquatic insects and are specialized in doing so. The lower lip of their mouth has sharp bristles, and is long and jointed. It folds back between the front legs and when an aquatic insect swims by the lip goes out to grasp the prey. Although metamorphosis is simple, the naiad and adult do not closely resemble one another. Fully grown the nymph crawls onto a water plant. Its shell splits down the back and out comes the adult dragonfly. Mosquito Facts Only the female mosquito takes the blood of humans, and other mammals. The male sips on plant juices. Female mosquitoes must have a blood meal before they can lay eggs. Lifecycle - Eggs are dropped in temporary pools. At least 400 eggs are laid in a neat raft arrangement. For a day or two the eggs float about, and then hatch into larvae called wrigglers or wiggle-tails. The larvae wriggle about getting food. Each larva has a breathing tube at the end of its body, which sticks up above the top of the water. This is how it gets its air. After several days the larva changes to a pupa, and a few days later a full grown mosquito comes out from the skin of the pupa. Fish Fish breathe oxygen from the water using gills. Water is taken in through the mouth and passed out the gill flaps, where there is an exchange of carbon dioxide for oxygen. Fish have slippery scales to protect them. Fish have a gas filled swim bladder to keep them afloat. Fish have external fertilization, where the female lays her eggs in the water and the male spreads his sperm on top. Largemouth Bass This species is typically found in weedy bays or backwaters with muddy bottom (14). Spawning takes place in early spring (14). The male clears a nest by fanning off silt from gravel or plant roots and guards the eggs till the young hatch and they are 2-3 weeks old (14). The young feed mainly on aquatic insects. Adults eat fish and crayfish (14). Bluegill Facts This is the most common fish to catch from the fishing dock at Bradford Woods during recreation. Bluegill are colorful fish reaching a length of about 12 inches (14). Their nests are constructed in colonies in sand or fine gravel, and may span up to 2 feet in diameter depending on the size of the defending male (14). Carp Facts The carp is related to the goldfish (14). It was originally introduced from China in 1877 (14). This fish often jumps out of the water during spawning, and migrates to shallow water in the spring to lay eggs that cling to plants and roots (14). Channel Catfish Facts These fish are smooth with broad flat heads and whiskers and do not have scales (14). 19

8 They can survive in waters of greatly reduced oxygen content, burrowing in the mud when the water dries up and hibernating regularly (14). Catfish depend more upon their sensory barbels rather than their eyesight to find food (14). They tend to feed more at night and during the rain (14). Crappie Facts Crappie are members of the sunfish family (14). Crappies generally grow to a weight of 1-3 pounds (14). They feed on a variety of organisms including small fish, insects and crustaceans that they find among vegetation and in open water (14). Minnow Facts Minnow are small fish reaching a maximum length of about 2 inches. They can often be confused with baby carp and bass, which have bulging bellies. These fish are often seen near the beach during aquatic life modules. Turtles Turtles do not have teeth. Instead their jaws have razor-sharp edges that can snip twigs and tear flesh (11). Turtles draw their head and legs partly or completely inside their shell for protection against predators (11). Female turtles come out the water to lay their eggs in a hole they dig in the dirt and sand. She then covers them up before she leaves. The eggs are incubated by the heat of the sun (11). The lower shell of a turtle is called the plastron and is jointed to the upper shell called the carapace (11). Many turtles can be found basking on logs at the lake, during sunny warm summer days. Turtles Common to Bradford Woods Box Turtle This species is not aquatic and can often be seen roaming around the forest floor. They still enter the water and often bath in pools and ponds. Because of a broad hinge across the forward third of the plastron, box turtles can draw up their lower shell inside the carapace. In this way they can completely box in all the soft parts of their bodies (3). Soft-shelled Turtle This species is often found by the beach during aquatic life modules. They are very flat and the upper shell is covered with a soft leathery skin. Frogs and Toads Frogs and toads absorb water through their skin so they don't need to drink (a). Frogs and toads have their eyes and nose on the top of their head so they can breathe and see when most of their body is under the water (a). Frogs can lay as many as 4000 jelly-covered eggs in a large clump known as frog spawn (a). Frogs vary much in color and pattern and can change color to a degree with their surroundings (1). Usually only male frogs and toads croak. They do this during the breeding season to attract females and warn away other males (a). Most male frogs and toads inflate a sac in their throat when they croak (1). Frogs are very fast and accurate jumpers. A leap can take only 3 tenths of a second. What is the difference between a frog and a toad? Toads have rough warty, skin and live mainly on land. Frogs on the other hand have smooth slimy skin and live mainly in water and wet places (1). Toads are usually plumper than frogs (2). A toad has a gland behind each of its eyes known as a paratoid gland. These glands ooze a liquid, which is toxic to other animals, when it is threatened. Frogs do not have these glands (2). Frogs and Toads Common to BW Wood Frog Its colors blend in with its habitat. It is soft brown like the leaves and leaf mold in the woods where it lives. Its hind legs are long and strong, allowing it to jump many times its length (3). 20

9 Spring peeper These male frogs can be heard calling around Bradford Woods for a mate in spring. The "Ee-EEP, eee-eeeep" sound is great to hear in the spring at the vernal ponds, especially on a night hike as this is when they are most active. They mate just after coming out from hibernation. The female peeper lays eggs one at a time, unlike other frogs that lay masses of spawn. She attaches each one to the stem of a plant under the water or even on the bottom of the pond. She may lay up to a thousand eggs. By the end of May the females will have laid their eggs and the males will have stopped calling (2). Gray Tree Frog Lives in trees and shrubs, clinging with the sticky pads on their toes (1). Spadefoot Toad Most toads burrow into the ground and the spadefoot toad is especially adapted to this habit as it has webbed feet that clear the way as it twists itself backward into the soil (3). Macroinvertebrates (Image 1) Macroinvertebrates are organisms that lack an internal skeleton and are large enough to be seen with the naked eye and are an integral part of wetland and stream ecosystems. Examples of macroinvertebrates include mayflies, stoneflies, dragonflies, rat-tailed maggots, scuds, snails, and leeches. These organisms may spend all or part of their lives in water. Usually their immature phases, larvae and nymph s, are spent entirely in water. Larvae do not show wing buds and are usually very different in appearance from the adult versions of the insects. Maggot is the term used for the larva stage. Nymphs generally resemble adults, but have no developed wings and are usually smaller. A variety of environmental stressors can impact macroinvertebrate populations. Urban and or agricultural runoff can produce conditions that some macroinvertebrates cannot tolerate. Sewage and fertilizers added to streams induce the growth of algae and bacteria that consume oxygen and make it unavailable for macroinvertebrates. Changes in land use from natural vegetation to a construction site or to poorly protected cropland may add sediment to the water. Sedimentation destroys habitats by smothering the rocky areas of streams where macroinvertebrates live. The removal of trees along the banks of a river and alteration of stream velocity or speed can both alter normal water temperature patterns in the stream. Some organisms depend on certain temperature patterns to regulate changes in their life cycles. Other stressors include the introduction of alien species and stream channelization. Some macroinvertebrates, such as the mayfly and stonefly nymphs and caddisfly larvae, are sensitive, intolerant, to changes in stream conditions brought about by pollutants. Some of these organisms will leave to find more favorable habitats, but others will be killed or will be unable to reproduce. Macroinvertebrates that may thrive in polluted conditions are called tolerant organisms. Other organisms, called facultative organisms prefer good stream quality but can survive polluted conditions. Temperature The water temperature of a lake is very important for water quality. Many of the physical, biological, and chemical characteristics of a lake are directly affected by temperature. For example, temperature influences are: The amount of oxygen that can be dissolved in water, The rate of photosynthesis by algae and larger aquatic plants, The metabolic rates of aquatic organisms, The sensitivity of organisms to toxic wastes, parasites, and diseases. Water temperature is usually affected by thermal pollution. Thermal pollution is an increase in water temperature caused by adding relatively warm water to a body of cooler water. Industries, such as nuclear power plants, and hydroelectric dams, may cause thermal pollution by discharging the warm water used to cool machinery into nearby aquatic communities. Storm water runoff from parking lots and streets also tends to be much warmer than the bodies of water into which they run. An indirect way that people affect water temperature is by removing trees that grow next to aquatic ecosystems. Among the benefits trees 21

10 provide for aquatic ecosystems are the cooling effect of their shade (keeping temperatures low) and the prevention of soil erosion. When soil erosion occurs it can increase water temperature. This occurs because soil erosion increases the amount of suspended solids carried by the river, or other waterway, making the water cloudy (turbid). These darker particles floating in the water absorb heat from the sun s rays much more effectively than would pure water. The more heat absorbed, the more the temperature rises. Dissolved Oxygen (Table 1) Aquatic animals need oxygen to live. Oxygen dissolves readily into water from the atmosphere until water is saturated. Oxygen is also produced by aquatic plants, algae, and phytoplankton as a by-product of photosynthesis. Dissolved Oxygen levels below 3ppm are stressful to most aquatic organisms. Dissolved Oxygen levels below 2 or 1ppm will not support fish. Levels of 5 to 6ppm are usually required for growth and activity. Dissolved Oxygen Percent Saturation is an important measurement of water quality. Cold water can hold more dissolved oxygen than warm water. For example, water at 28 degrees Celsius will be 100% saturated with 8ppm dissolved oxygen. However, water at 8 degrees Celsius can hold up to 12ppm of oxygen before it is 100% saturated. High levels of bacteria from sewage pollution or large amounts of rotting plants can cause the percent saturation to decrease. This can cause large fluctuations in dissolved oxygen levels throughout the day, which can affect the ability of plants and animals to thrive. Fluctuations also occur over the course of the year due to average water temperature. As the temperature rises as summer approaches, DO levels decrease and animals that require high levels become more scarce. As the temperature decreases through winter, DO levels rise again, generally resulting in a high diversity of aquatic organisms in the spring months before DO levels fall again. A dissolved oxygen level refers to the amount of oxygen (in milligrams) that is dissolved in a liter of water. It can also refer to a percentage, or the amount of oxygen that is dissolved compared to the amount that could be dissolved, similar to relative humidity. Dissolved oxygen is critical in aquatic ecosystems because plants and animals depend on the oxygen to survive. Dissolved oxygen levels are a good indicator of an aquatic ecosystems overall health. Almost all living things, even plants, need oxygen in order to survive. An exception to this rule is anaerobic decomposers, which make up a fairly small percentage of living organisms. For example, fish breath DO, not water, through their gills. Fish are unable to separate the oxygen from individual water molecules (H 2 0). They instead sift out the DO through the permeable membranes of their gills. The oxygen directly enters the bloodstream. Aquatic insect larvae, tadpoles, salamander larvae, and others breathe underwater in the same way. All of these creatures live within a certain range of DO. If DO levels become too high, air bubbles develop in the bloodstream and slow or stop the flow of blood. If high DO levels persist for too long these animals will die. If DO levels are too low, aquatic animals will not be able to get the amount of oxygen necessary to maintain critical body functions. If low DO levels continue for too long, these animals will suffocate and die. Aquatic plants affect dissolved oxygen levels by both consuming (during respiration) and producing (as a byproduct of photosynthesis) it. Algae and other aquatic plants require oxygen for consuming the energy they produce in photosynthesis (i.e. breaking down the sugars into a usable form), a process called respiration. If DO levels drop too low the plants will not have enough oxygen to feed themselves and will eventually starve to death. Though dissolved oxygen is very important to aquatic ecosystems, it is not always stable. There are several factors that affect the levels of DO in a body of water. The amount of mixing a body of water does with its surrounding atmosphere affects the level of DO. Most of the DO in water comes from the atmosphere. Waves on lakes and tumbling water (over rocks, for example) act to mix atmospheric oxygen with water. Therefore, a stream with more turbulence on its sur- 22

11 face will have higher DO levels than a similar, but more stagnant body of water. Plants can impact DO levels, as briefly discussed above. Non-rooted aquatic plants, such as Algae, and rooted ones, such as Duckweed or Cattails, deliver oxygen to water through the process of photosynthesis. Because of this, DO levels rise from morning through the afternoon during the peak of photosynthesis. However, plants and animals continue to respire and consume oxygen. As a result DO levels fall to a low point just before dawn. When these plants die, the decaying process furthers. A third factor affecting DO levels is temperature. Gases, like oxygen, dissolve more easily into cooler water (the lower the temperature, the higher the amount of oxygen that can be dissolved). Therefore an unnaturally warm lake or stream will hold harmfully less DO than the plants and animals which have adaptations for that specific environment. A less significant, but important factor affecting levels of DO is air, atmospheric and barometric, pressure. A lower air pressure will result in higher levels of DO. That is why the level of DO decreases the higher in altitude one travels. Even slight changes in air pressure will affect the levels of DO in an aquatic ecosystem. The most significant factor that affects the level of DO is the presence or absence of organic waste. Organic material, something that was part of a living organism, that enters the water is immediately broken down by aerobic, consuming oxygen, bacteria. If there is a build-up of organic material in an aquatic ecosystem the amount and activity of aerobic bacteria will increase and consume more oxygen. This will lower DO levels dramatically if continued. Pollution is the most common outside cause of decreased DO levels. Pollution that takes the form of raw sewage from cities or agricultural runoff increases the level of organic waste and depletes the supply of DO. Pollution can also take the form of temperature change, called thermal pollution, which is commonly created by the warm out wash water produced by hydroelectric dams. This too can decrease levels of DO. The low levels of dissolved oxygen in turn cause the death of more plants and animals, which must then be decomposed by an even greater number of aerobic bacteria. This begins a cycle, which, if left unchecked, results in severe deterioration of the aquatic ecosystem. ph (Image 2) Water contains both hydrogen (H+) ions and hydroxide (OH-) ions, which are linked together to form the water molecule (H 2 O). Acid contributes the hydrogen ions. The stronger the acid, the higher the concentration of hydrogen ions. Hydroxide ions are contributed by bases. The stronger the base, the higher the concentration of hydroxide ion. A ph test measures the concentration of hydrogen and hydroxide ions in the water. The ph of each liquid or substance is measured on a scale of 0 to 14. A neutral liquid has a ph value of 7.0, which means that there are equal amounts of hydrogen and hydroxide ions. If water has more hydrogen ions than hydroxide ions, it is considered acidic and has a ph less than 7. If it has more hydroxide ions than hydrogen ions, it is considered basic and has a ph value greater than 7. Changes in the ph of water are very important to aquatic organisms. Most organisms have adaptations that suit them to water of a specific ph and may die if the ph changes even slightly. At extremely high or low ph values the water can become entirely unsuitable for all organisms. Serious problems occur in lakes with a ph below 5. At this ph or below immature stages of aquatic insects and young fish can be damaged simply by the water and its acidic affects. Highly acidic water can cause heavy metals, such as copper and aluminum, to be dissolved into the water in quantities that are greater than normal. These heavy metals can accumulate on the gills of fish or cause deformities in young fish, greatly reducing their chances for survival. Although ph can be affected by runoff from mining operations, in south central Indiana it is generally affected by acid deposition. In this process air pollution (nitrates and sulfates) 23

12 from urban areas collect in the atmosphere and mix with the water in clouds to produce nitric or sulfuric acid. This acid enters the aquatic ecosystem in the form of rain, snow, or groundwater seepage. An overall ph change of as little as 1.4 is enough to significantly disturb aquatic communities. 24

13 Image 1 Sensitive Facultative Tolerant 25

14 Table 1 Temp 0 ppm 4 ppm 8p ppm Degrees C

15 Image 2 27

16 Waterlogged Areas where water is found (pass out to students) Oceans Percentages (for your calculations) % 20 Ft. Conversion (for your calculations) 19 ft. 5 in. Glaciers and Icecaps % 5 in. Groundwater % 1.5 in. Freshwater Lakes % 1/4 in. Inland Seas and Salt Lakes % 1/4 in. Atmosphere % 1/32 in. Rivers % 1/64 in. 28

17 Benthic Bedlam Front of Card Caddisfly Intolerant Mayfly nymph Intolerant Stonefly nymph Intolerant Back of Card I am intolerant of low oxygen levels. Hop across field stopping to gasp for breath every 5 seconds I increase oxygen absorption by moving my gills. Flap arms and spin in circles to cross the field. When oxygen levels drop, I use my abdomen to increase the flow of water over my body. Do push ups every 10 steps across field. Dragonfly nymph Facultative Walk across the field. Damselfly nymph Facultative Midge larva Tolerant Rat-tailed maggot Walk across the field. Run across the field. Run across the field. Tolerant You may choose to create your own cards and add images of the macro invertebrates to prepare students for the types of critters they will be seeking later in the day. 29

18 Standards Grade 3 English/ Language Arts 3.SL.2.3 Demonstrate knowledge and use of agreed upon rules for discussions and identify and serve in roles for small group discussions or projects. 3.SL.2.4 Ask questions to check understanding of information presented, stay on topic, and link comments to the remarks of others. 3.SL.2.5 Explain personal ideas and understanding in reference to the discussion. 3.SL.3.1 Retell, paraphrase, and explain the main ideas and supporting details of a text read aloud or information presented in diverse media and formats, including visually, quantitatively (e.g., charts and graphs), and orally. Mathematics 3.M.2 Choose and use appropriate units and tools to estimate and measure length, weight, and temperature. Estimate and measure length to a quarter-inch, weight in pounds, and temperature in degrees Celsius and Fahrenheit. Science Investigate and recognize that sound moves through solids, liquids and gases (e.g., air) Observe and describe how light is absorbed, changes its direction, is reflected back and passes through objects. Observe and describe that a shadow results when light cannot pass through an object Identify fossils and describe how they provide evidence about the plants and animals that lived long ago and the nature of their environment at that time Describe natural materials and give examples of how they sustain the lives of plants and animals Describe how the properties of earth materials make them useful to humans in different ways. Describe ways that humans have altered these resources to meet their needs for survival. Grade 4 English/Language Arts 4.SL.2.1 Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) on grade-appropriate topics and texts, building on others ideas and expressing personal ideas clearly. 4.SL.2.3 Demonstrate knowledge and use of agreed -upon rules for discussions and carry out assigned roles. 4.SL.2.5 Review the key ideas expressed and explain personal ideas in reference to the discussion. 4.SL.3.1 Summarize major ideas and supportive evidence from text read aloud or information presented in diverse media and formats, including visually, quantitatively, and orally. 4.W.1 Write routinely over a variety of time frames and for a range of discipline-specific tasks, purposes, and audiences; apply reading standards to support reflection and response to literature and nonfiction texts. Mathematics 4.NS.1 Read and write whole numbers up to 1,000,000. Use words, models, standard form and expanded form to represent and show equivalent forms of whole numbers up to 1,000, NS.2 Compare two whole numbers up to 1,000,000 using >, =, and < symbols. 4.C.4 Multiply fluently within M.1 Measure length to the nearest quarter-inch, eighth-inch, and millimeter. 4.M.3 Use the four operations (addition, subtraction, multiplication and division) to solve real-world problems involving distances, intervals of time, volumes, masses of objects, and money. Include addition and subtraction problems involving simple fractions and problems that require expressing measurements given in a larger unit in terms of a smaller unit. 4.DA.1 Formulate questions that can be addressed with data. Use observations, surveys, and experiments to collect, represent, and interpret the data using tables (including frequency tables), line plots, and bar graphs. 4.DA.2 Make a line plot to display a data set of measurements in fractions of a unit (1/2, 1/4, 1/8). Solve problems involving addition and subtraction of fractions by using data displayed in line plots. 4.DA.3 Interpret data displayed in a circle graph. Science Demonstrate and describe how smaller rocks come from the breakage and weathering of larger rocks in a process that occurs over a long period of time Describe how wind, water and glacial ice shape and reshape earth s land surface by eroding rock and soil in some areas and depositing them in other areas in a process that occurs over a long period of time Investigate earth materials that serve as natural resources and gather data to determine which ones are limited by supply Observe, compare and record the physical characteristics of living plants or animals from widely different environments. Describe how 30

19 Standards each plant or animal is adapted to its environment Design investigations to explore how organisms meet some of their needs by responding to stimuli from their environments Describe a way that a given plant or animal might adapt to a change arising from a human or non-human impact on its environment. Grade 5 English/ Language Arts 5.SL.2.1 Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) on grade-appropriate topics and texts, building on others ideas and expressing personal ideas clearly. 5.SL.2.5 Review the key ideas expressed and draw conclusions in reference to information and knowledge gained from the discussions. 5.SL.3.1 Orally summarize or respond to a written text read aloud or information presented in diverse media and formats, including visually, quantitatively, and orally. Mathematics 5.NS.1 Use a number line to compare and order fractions, mixed numbers, and decimals to thousandths. Write the results using >, =, and < symbols 5.NS.5 Use place value understanding to round decimal numbers up to thousandths to any given place value. 5.M.1 Convert among different-sized standard measurement units within a given measurement system, and use these conversions in solving multi-step real-world problems. 5.DS.1 Formulate questions that can be addressed with data and make predictions about the data. Use observations, surveys, and experiments to collect, represent, and interpret the data using tables (including frequency tables), line plots, bar graphs, and line graphs. Recognize the differences in representing categorical and numerical data. 5.C.8 Add, subtract, multiply, and divide decimals to hundredths, using models or drawings and strategies based on place value or the properties of operations. Describe the strategy and explain the reasoning. Science Describe and measure the volume and weight of a sample of a given material Describe the difference between weight and mass. Understand that weight is dependent on gravity and mass is the amount of matter in a given substance or material Observe and classify common Indiana organ- isms as producers, consumers, decomposers, predator and prey based on their relationships and interactions with other organisms in their ecosystem Investigate the action of different decomposers and compare their role in an ecosystem with that of producers and consumers Investigate technologies that mimic human or animal musculoskeletal systems in order to meet a need Investigate the purpose of prototypes and models when designing a solution to a problem and how limitations in cost and design features might affect their construction Design solutions to problems in the context of musculoskeletal body systems. Using suitable tools, techniques and materials, draw or build a prototype or model of a proposed design. Social Studies Physical Systems: Identify major sources of accessible fresh water and describe the impact of access on local and regional communities. Grade 6 English/Language Arts 6.SL.2.1 Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher led) on grade-appropriate topics, texts, and issues, building on others ideas and expressing personal ideas clearly. 6.SL.2.2 Elaborate and reflect on ideas under discussion by identifying specific evidence from materials under study and other resources. 6.SL.2.4 Pose and respond to specific questions with elaboration and detail by making comments that contribute to the topic, text, or issue under discussion. 6.SL.3.1 Interpret information presented in diverse media and formats (e.g., visually, quantitatively, orally) and explain how it contributes to a topic, text, or issue under study. Mathematics 6.GM.1 Convert between measurement systems (English to metric and metric to English) given conversion factors, and use these conversions in solving real-world problems. 6.C.6 Apply the order of operations and properties of operations (identity, inverse, commutative properties of addition and multiplication, associative properties of addition and multiplication, and distributive property) to evaluate numerical expressions with nonnegative rational numbers, including those using grouping symbols, such as parentheses, and involving 31

20 Standards Science Describe specific relationships (i.e., predator and prey, consumer and producer, and parasite and host) between organisms and determine whether these relationships are competitive or mutually beneficial Describe how changes caused by organisms in the habitat where they live can be beneficial or detrimental to themselves or to native plants and animals Describe how certain biotic and abiotic factors such as predators, quantity of light and water, range of temperatures and soil composition can limit the number of organisms an ecosystem can support Recognize that plants use energy from the sun to make sugar (i.e., glucose) by the process of photosynthesis Describe how all animals, including humans, meet their energy needs by consuming other organisms, breaking down their structures, and using the materials to grow and function Recognize that food provides the energy for the work that cells do and is a source of the molecular building blocks that can be incorporated into a cell s structure or stored for later use. Social Studies Environment and Society: Explain the impact of humans on the physical environment in Europe and the Americas. 32