Water Quality Unit - Learning Set 3 (nov. 09)

LEARNING SET 3: WHAT AFFECTS WATER QUALITY? What is the Water Like in Our River?





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LEARNING SET 3: WHAT AFFECTS WATER QUALITY? CONTENTS Science Understanding for Teachers

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Lesson 8: Fertilizer Investigation

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Lesson 9: pH Investigation

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Lesson 10: Variables Affecting Water Quality

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Lesson 11: Revisiting the Fertilizer and pH Investigations

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Lesson 12: Water Quality Testing

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Lesson 13: Analyzing Water Quality Tests and Making Conclusions

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Lesson 14: Bioindicators

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Lesson 15: What Do Organisms Tell Us

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SCIENCE UNDERSTANDING FOR TEACHERS Purpose In this learning set, students investigate specific water quality variables. They measure temperature, dissolved oxygen (DO), biological oxygen demand (BOD), fecal coliform, pH, turbidity, phosphates and nitrates. The combined effects of these variables determine overall water quality. Using test results for each variable, students create an overall, weighted Water Quality Index (WQI). This numerical value can be translated into a qualitative statement about water quality in their river. Next, students investigate overall habitat quality through the biodiversity in their river. Using bioindicator organisms and tolerance values, students determine the overall Pollution Tolerance Index (PTI) of their river. Students learn that the presence or absence of various indicator organisms can be an indication of habitat quality, including water quality through biological response. Students are looking for agreement between what the PTI and WQI methods indicate about the health of the river.

Dissolved Oxygen Dissolved oxygen (DO) refers to the concentration of molecular oxygen (O2) dissolved in river water. Aquatic animals need oxygen to breathe and live, but they cannot use the oxygen in a water molecule (H2O). It is bonded too strongly to the hydrogen atoms (2H). Aquatic animals can only use oxygen in its elemental form (O2). Most of the oxygen incorporated into the water originates from the atmosphere. However, plant production of oxygen through photosynthesis also provides a substantial fraction of total dissolved oxygen. The amount of oxygen (O2) that can dissolve into water is largely dependent on the temperature and the physical churning or turbulence of the water. Cool waters can dissolve more oxygen than warm waters. Likewise, quickly flowing, turbulent areas (i.e. cascades and riffles) have higher concentrations of dissolved oxygen than slowly moving or still water (i.e. pools and glides). Dissolved oxygen (DO) is essential for the survival of aquatic animals. Organisms such as fish and some macroinvertebrates use their gills to extract dissolved oxygen from the water to breathe and live. As a result, the concentration of oxygen strongly influences which organisms are able to survive in the river. The general trend is for a greater diversity of animals to live in well oxygenated water than in poorly oxygenated water. Rivers should be saturated with dissolved oxygen by the very nature of their movement. Rivers that fall below 90% saturation are considered to be under serious environmental strain.

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Biological Oxygen Demand The Biological Oxygen Demand (BOD) of a river is the amount of oxygen used by microorganisms while decomposing organic matter. Microorganisms break down organic matter and combine it with oxygen (oxidation). As organic material and decomposition increase, biological oxygen demand increases and dissolved oxygen decreases. BOD measurements are used to assess the level of organic pollution in aquatic ecosystems. High BOD values most often point to considerable sewage contamination. However, it can also be an indication of increased organic material and decomposition, from excess nutrients (e.g. fertilizer runoff) in the river. Reservoirs or lakes created by damming a river can also have a high BOD. Rivers that are forced to be still are robbed of their natural potential to oxygenate the water through movement. Remember that moving water incorporates more dissolved oxygen than still water. High levels of organic waste and BOD deprive other animals of the dissolved oxygen they require for survival. Some animals are more tolerant of low oxygen levels, such as carp, catfish, sewage worms and midge larvae. Other animals, such as trout, caddisflies and stone-flies, require much more oxygen to survive.

Fecal Coliform Fecal coliform (FC) is a type of bacteria found in the digestive system and feces of humans and other animals. These bacteria can enter the river through sewage overflow, direct human and animal deposit and agricultural runoff containing animal wastes. Fecal coliform bacteria do not cause illness. However, they are easy to measure and are often found in conjunction with pathogens that can make people sick. Therefore, in the interest of practical monitoring, fecal coliform bacteria are measured as an indication of the severity of harmful

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pathogens. A high concentration of fecal coliform indicates that a high concentration of pathogenic organisms may be present.

National Coliform Standards in colonies/100 ml Drinking water 1 TC* Total body contact (swimming) 200 TC Partial body contact (boating) 1000 TC Treated sewage discharge 200 TC *Total Coliform (TC) includes bacteria from cold-blooded animals and various organisms. According to some research, total coliform counts are normally about 10 times higher than fecal coliform (FC) counts. *= Return The Michigan standard for fecal coliform in industrial output is 200 FC/100 ml of water. This standard st

is seasonally applicable (i.e. when beaches are open) and can be suspended November 1 through th

April 30 . The standard can also be exceeded “if due to uncontrollable non-point sources, flooding, accident, or emergencies that affect a sewer or wastewater treatment system,” according to the Environmental Protection Agency (EPA). With such loose regulation, Michigan fecal coliform standards are ineffective and associated pathogens are often spewed into Michigan waterbodies.

pH The pH test measures how acidic or basic a sample is. The pH scale ranges from 0 (very acidic) to 14 (very basic). Neutral samples have a pH of 7. +

The pH test measures the concentration and ratio of free hydrogen ions (H ) to free hydroxide ions +

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(OH ). Neutral samples have a pH of 7 with equal and low concentrations of H and OH ions. If a -

+

sample has more OH than H ions, it is considered basic and has a pH greater than 7. If a sample has +

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more H than OH ions, it is considered acidic and has a pH less than 7. It is important to remember that the pH scale is log scale. For every unit of change on the pH scale, there is a ten-fold change in acidity. For example, a sample with a pH of 6 is 10 times more acidic than a sample with a pH of 7 and 100 times more acidic than a sample with a pH of 8.

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Changes in acidity can be particularly devastating to aquatic plants and animals. Most living things have adapted to a specific range of pH values. Although the range may be fairly large, deviation from this range can have immediate and dire consequences for stream organisms. Spring snowmelts can create very acidic conditions in the river. As the snow melts, it releases the acidic water it contained originally, plus all pH ranges that support aquatic life (Stapp and Mitchell, 1995).

the dry deposition that settled out of the air and into the snow during the winter. As a result,

spring snowmelts can create immediate flashes of very acidic water. Rivers can handle gradually melting snow packs more effectively than sudden, large pulses of acidic inputs. Michigan is fortunate to have soils with a natural buffering capacity to counter acidic inputs. During the last glaciation, basic soil and rock (i.e. calcium carbonate) were carved from the Canadian shield and transported to Michigan in the moving ice. As the ice retreated, it left this basic material and the ability to moderate acidic inputs. As a result, our soils and streams are naturally, slightly basic and able to handle minimal acidic inputs. Other areas are not as fortunate. Areas such as the Adirondack and Catskill Mountains in New York, the mid-Appalachian highlands, and the mountainous areas of the Western United States are suffering from acid rain inputs into their lakes and streams. They did not receive the benefits of processed basic materials, and are further impacted in locations with non-porous bedrock. In places like the Adirondack Mountains, water accumulates on the rocky surface of the area, collecting dry deposition from the atmosphere and acid rain. As a result, one of the most acidic lakes reported by the US EPA can be found in the Adirondack mountains. That is Little Echo Lake with an average pH value of 4.2. The natural buffering capacity of the stream can be exhausted. If we continue to add acidic pollutants to our rivers, we will eventually exceed the soil’s ability to mitigate our inputs. Therefore, it is important to plan for the future. Legislation that limits pollutants causing acid rain (e.g. nitrogen and sulfur oxides from automobiles and coal-burning power plants), preserves stream and air quality. The discussion of stream pH is an excellent opportunity to connect this learning set to the “What is the Air like in Our Community?” curriculum if you have already done it. Air pollution and acid rain are the primary sources of acidity in our lakes and rivers.

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Phosphates and Nitrates Phosphates and nitrates are negatively charged, nutrient ions necessary for the growth of plants and -

animals. Phosphate (PO4 ) is composed of one phosphorous atom and four oxygen atoms. Nitrate -

(NO3 ) is composed of one nitrogen atom and three oxygen atoms. Phosphates are essential in the metabolic reactions and growth of plants and animals. The concentration of phosphate is normally the “growth-limiting” variable in fluvial ecosystems because it is naturally scarce. Phosphates are attracted to soil particles and organic material. Therefore, soil is the largest natural sink and input (through erosion) of phosphates in rivers. Plants quickly use up the small amounts of phosphates that are released.

Nitrates also act like a plant and animal nutrient. All plants and animals require nitrogen to produce proteins essential for growth. However, nitrates are naturally very abundant and do not normally limit the growth of stream plants and animals. Therefore, stream organisms are not as sensitive to increases in nitrates. Phosphate increases are the biggest nutrient increase problem, because growth inhibition is lost and more of each nutrient can be used. When this happens, plant populations explode. In fact, phosphate increases are notorious for causing algal blooms, which color the water green. The increased plant growth leads to a higher biological oxygen demand (BOD) as the plants begin to decompose, which in turn leads to oxygen depletion in the river. Human activities can increase phosphate and nitrate concentrations in fluvial ecosystems. These nutrients are quite often found together. Agricultural sources include fertilizer, animal waste and increased erosion by influencing the transport of phosphorous. Major nutrient sources in urban areas include treated and untreated sewage, laundry detergents, and fertilizer runoff.

Total Solids Total solids is a measure of suspended and dissolved solids in the water. Dissolved solids are those that cannot be filtered from a sample of water. Suspended solids are those that can be filtered out and removed. Total solids can be measured by evaporating off the water, leaving behind the dissolved and suspended solids. Dissolved solids include inorganic and organic substances. Dissolved inorganic materials are found in ionic form. Many of which are necessary for the maintenance of aquatic life including nitrates, phosphates, iron, sulfur and many other ions found in a water body. Dissolved organic material originates as biological products of soil, plants, and animal material. Dissolved organic material is roughly 50% carbon and can be used as a food source for aquatic microorganisms.

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High concentrations of suspended solids can cause serious water quality problems. Suspended solids include soil particles from erosion, organic material, industrial waste, sewage and plankton. High concentrations of suspended solids decrease water clarity, blocking the transmission of light through the water, hindering photosynthesis, and absorbing the sun’s energy as heat. At the same time, suspended solids can bind to toxic substances and heavy metals. Also, by increasing water temperature, suspended solids indirectly decrease dissolved oxygen.

Turbidity Turbidity is a measure of water clarity. The greater the turbidity, the more “murky” or cloudy the water. Measuring turbidity is an indication of the abundance of total solids in the water. Turbid water can hinder photosynthesis lowering dissolved oxygen. As a result, turbid water is often(but not always) poor quality water.

Temperature Temperature measures how hot or cold something is and can be defined operationally as what a thermometer measures. Temperature changes can have direct and indirect impacts on aquatic organisms and water quality. Many rivers are groundwater fed and therefore cold. As a result, many stream organisms are adapted to consistently cold temperatures. As we continue to decrease the influence of groundwater and add thermal pollution, we are increasing water temperatures, while decreasing the survival chances of many aquatic organisms. Thermal Pollution Water has a very high heat capacity, making it resistant to temperature changes. Compared to other substances, it takes more energy to raise the temperature of one gram of water by 1˚ C. This physical property of water moderates daily and seasonal climactic changes in temperature. Large waterbodies also have considerable thermal inertia, a combination between the heat capacity and the size of the waterbody. As the size of the waterbody increases, it is more difficult to change the overall water temperature. Therefore, thermal interia is influential in sizable rivers and lakes. As a result of thermal inertia, large waterbodies are naturally warmer than the air in the winter and cooler in the summer. This property of water has made it an attractive “heat sink” for industrial processes that require cooling. Industrial activities, such as power plants, can use river water to cool machinery. Afterwards, the water is put back into the river. The water that is released is often much warmer than it was prior to extraction. Industrial cooling is a major source of thermal pollution. Measuring water temperatures above and below a suspected source of thermal pollution can indicate the source and magnitude of thermal pollution.

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Urbanization alters the water cycle and increases water temperatures. Urbanization often removes streamside vegetation. This eliminates a source of shade that would normally cool the river. Urban pressures also increase erosion by increasing surface runoff and removing vegetation. This results in high concentrations of suspended solids (i.e. turbidity), which also increases water temperatures. Urban pressures also result in greater temperature variation by increasing surface runoff. Urban runoff can be colder than groundwater in the winter, or much warmer in the summer as it moves over heated impervious surfaces, such as roads and parking lots. The net result of increasing urban pressures is warmer average temperatures with greater variation. Direct Impacts Water temperature is one factor that determines which organisms are present in the river. Aquatic animals can be very sensitive to temperature changes. A week or two of high temperatures each year may make a stream unsuitable for the existence of sensitive organisms, even though temperatures are within an acceptable range throughout the rest of the year. Different species have different temperature requirements, but all species can tolerate slow, seasonal changes better than rapid changes. Thermal stress and shock can occur when temperatures change more than 1˚ to 2˚ C in 24 hours. High water temperatures increase the sensitivity of aquatic animals to toxic waste, disease and parasites. This can be a result of increased parasite populations, or increased susceptibility during thermal stress or shock. Optimum water temperatures may change for each stage of life. For instance, fish eggs and larvae usually have narrower temperature requirements than adult fish. Temperature changes can alter animal behavior. Temperature cues biological functions in many aquatic animals, such as hibernation and emergence, feeding, reproduction and metabolism. Changing water temperature can entice animals to behave in ways that are not optimal for their survival, such as migrating when they should be hibernating. Some organisms do not perform vital functions at all (e.g. reproduction) until temperature cues are just right. As a result, altering temperature can change animal behavior and ultimately jeopardizes their long-term survival. Indirect Impacts Elevated water temperatures directly and indirectly decrease dissolved oxygen in the stream. Warmer temperatures decrease dissolved oxygen by increasing plant production, decomposition and the BOD of the river. Likewise, increasing water temperatures increase animal metabolism and respiration. This also leads to the depletion of dissolved oxygen in the river.

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Water Quality Index (WQI) Students will determine the overall Water Quality Index (WQI) for their river. This index is determined by the weighted influence of 8 water quality variables. These variables include temperature, dissolved oxygen (DO), biological oxygen demand (BOD), fecal coliform, pH, turbidity, phosphates and nitrates. In order to create an overall WQI, raw water quality measurements are translated into comparable numerals. Each test result is translated into a “ranking” through the tables provided for each variable. This results in 8 “ranks”, one for each variable. Each variable is also “weighted”. Weighting each variable depicts the fact that each variable influences water quality to a different degree. Each rank is multiplied by the respective weight for each variable. The sum of the products is the WQI value. This value can be translated into a qualitative statement about water quality (i.e. excellent, good, fair and poor).

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Biodiversity and Bioindicators Biodiversity refers to the variety of living things in a given area. Biodiversity and individual populations are maximized when habitat conditions are optimal. As a result, biodiversity is often used as an indication of habitat quality, including water quality. When habitat conditions change, plant and animal communities are impacted according to their pollution tolerance. While very tolerant species can withstand large changes in their environment, intolerant species may be eliminated from the changing habitat. As a result, the presence or absence of certain plant and animal species can be an indication of overall habitat quality. Species that react in predictable ways to changes in their environment are known as bioindicators. Creatures that are very sensitive to changes or variation in water quality may be exterminated from the river. These species will be replaced by organisms that are more tolerant of changing conditions. Unfortunately, once exiled from the river, it is unlikely that the sensitive species will ever be able to return. As a result, changing river conditions can result in extinction from that site and possibly all other sites as well. The net result can be an immediate loss of biodiversity, and an eventual loss of life entirely.

Benthic Organisms as Bioindicators Benthic macroinvertebrates are bottom dwelling, aquatic invertebrates (organisms without a backbone) that can be seen with the unaided eye. These organisms are very important in the stream food web and can be very sensitive to water quality changes. In many cases, benthics are the most important organisms connecting the flow of energy between primary producers (plants) and larger organisms. Many macroinvertebrates found in rivers are larval stages of terrestrial insects such as the dragonfly and black fly. Other common benthic organisms include snails, worms, leeches and crustaceans. Benthic macroinvertebrates are easy to collect and are often used to determine sitespecific, long-term water quality. Unlike, chemical and physical tests that determine present concentrations of various pollutants, macroinvertebrate presence and absence provides information about present water quality and past water quality through biological response. The use of macroinvertebrates as bioindicators assumes that polluted sites have fewer organisms than clean sites and that the presence or absence of a certain organism is a direct result of habitat quality. Also, the information provided by macroinvertebrate collections can be considered relatively sitespecific because many macroinvertebrates migrate only short distances. Macroinvertebrates can be subdivided according to feeding guilds, groupings according to feeding habits. The functional feeding groups are: shredders who eat and/or live in dead plant and animal material, collectors who eat smaller pieces of dead organic material, filterers who filter out even smaller particles out of the water, grazers and scrapers who eat only live algae, and predators who

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eat other benthics (live prey). Macroinvertebrates are often categorized by functional groups, because it is difficult to identify them to family, genus or species. At times it is more important to know the role that each individual plays in the stream ecosystem than its specific name. Sampling Benthic Organisms Benthic organisms can be located and collected where they feed or rest. Many benthic organisms can be found hiding and feeding in stream vegetation. Organisms that require high levels of dissolved oxygen can be found in riffles where water is flowing over rocks. Benthic organisms that eat dead plant material are often found under leaves near the stream bank. Macroinvertebrate populations vary by season. Keep this in mind. For instance, organisms that feed on fall leaf litter are very abundant in the fall of the year. This does not mean that collection is impossible at other times of the year. Populations may be maximized at certain times of the year, but they are still present throughout the rest of the year. The real trouble may be finding them in a life stage that you recognize. Do not get discouraged if you are having trouble collecting benthic organisms. It can be difficult to sample the majority of the organisms that are present and nearly impossible to collect them all. Interpret the results of your collection as a whole. If you do not find a particular organism, it does not mean that it is definitely not in the river. It simply means that you did not find one. If the majority of the insects that you collect indicate that the water quality is ‘fair’, for instance, stick with it. Do not change your evaluation simply because a few of the other organisms that indicate ‘fair’ water quality were not found.

Pollution Tolerance Index Students will be using a Pollution Tolerance Index (PTI) to do a qualitative study of benthic biodiversity in their river. A PTI is useful for detecting moderate to severe pollution. It is based on the presence of indicator organisms (i.e. bioindicators) and tolerance levels. Indicator organisms are

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those that react in predictable ways to habitat changes. This method assumes that the presence or absence of a certain organism is a direct result of habitat quality, including water quality.

In order to create a PTI value, each organism is assigned a value relative to its sensitivity to water quality changes. In this PTI, individual tolerance values/groupings range from 1 to 4. Low values are assigned to ‘tolerant’ organisms that can withstand severe water quality changes or degradation. High values signify that the organism is very sensitive to changes in water quality and can be easily eliminated from the site. As a result, the presence of organisms with high indicator values (e.g. caddisfly larvae) implies that the river is healthy. The absence of many of these organisms indicates poor stream health. Students determine the PTI for their stream using the illustrated key and worksheet provided. First, students identify each organism by matching the organisms to the pictures. As they identify each organism, they mark a one on the worksheet by its name. Each type of organism only gets one number. Therefore, this method only provides information about biodiversity and does not reflect the concept of abundance. Next, all the ones are summed up for each group and multiplied by the group number (i.e. tolerance value). The sum of these values is the overall PTI, which translates into a qualitative estimation of stream quality (i.e. excellent, good, fair and poor). Students are looking for agreement between the overall Water Quality Index and the Pollution Tolerance Index. Hopefully, the two tests will result in the same qualitative statement about the

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health of the river. Keep in mind that the PTI relayed information about the entire health of the stream ecosystem. The WQI only assessed 8 water quality variables. The PTI actually tells you much more about stream health, while the WQI gives a good indication of water quality specifically. If the WQI and PTI do not agree, the difference can be an indication of the physical condition of the stream habitat, which can be difficult to measure or quantify.

Summary In this learning set, students investigate the habitat quality of their river, including water quality. Through benthic organism collections and water quality tests, students make the connection between water quality, habitat quality and biodiversity. At the termination of this learning set, students should have a good understanding of several water quality issues and the impact that they have on aquatic organisms and human users.

Science Understanding Resources Field Manual for Water Quality Monitoring from GREEN Chapter 3: Nine Water Quality Tests. This chapter discusses physical and chemical factors, their sources and their effects and methods of testing them. Chapter6: Benthic Macroinvertebrates. This chapter discusses multiple methods for benthic macroinvertebrate collection and several specific organisms that students may find. Nine Water Quality Tests Compiled by Karen Amati. Provides background for students about each of the nine physical and chemical factors that impact water quality in terms of what they are, their sources and their affects. The reading also describes how to perform each test in terms of how students will perform the tests during the project. th

th

Water Studies for Younger Folks: A Water Activities Manual for 5 -8 Grades The entire book gives you and your students background information on the factors, how to test the factors, their sources, and their effects.

Teacher Terms to Know +

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Acidic-having a greater concentration free hydrogen ions (H ) than hydroxide (OH ) ions. [H ]>[OH ] Algal bloom-rapid growth of algae stimulated by excess nutrients. -

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Basic-having a greater concentration of free hydroxide ions (OH ) than hydrogen ions (H ) ions. [H +

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]<[OH ]; same as alkaline

Benthic-(adj.) bottom-dwelling; (n.) bottom-dwelling organism Biodiversity-biological diversity in an environment as indicated by the number of different plant and animal species Bioindicator- a living organism that reacts in a predictable way to changing habitat conditions

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Biological Oxygen Demand (BOD)-the amount of oxygen required by microorganisms for the decomposition of organic material; same as biochemical oxygen demand Buffering Capacity- ability to neutralize both acids and bases and thereby maintaining the original acidity or basicity of the solution Cascade-an area of a stream or river where the flows are very turbulent usually when moving over large boulders and considerably changing elevation Collector- organisms that eat small pieces of dead organic material Dissolved Oxygen (DO)-molecular oxygen (O2) dissolved in river water Fecal Coliform- bacteria found in the colon and feces of humans and animals Filterers- organisms that eat by straining small food particles out of the water Glide-a area of a the stream having laminar flows, very smooth and continuous; where the surface of the moving water appears very calm and flat Grazers- organisms that consume live algae and diatoms Heat Capacity- the amount of energy it takes to warm one gram of a liquid 1 degree Celsius. Herbivore-eats plant material Macroinvertebrate-invertebrates (organisms without a backbone) that can be seen with the unaided eye Metabolic reaction- the chemical changes in living cells by which energy is provided for vital processes and activities and new material is assimilated Nitrate-negatively charged, nutrient ion composed of one nitrogen atom and three oxygen atoms -

(NO3 ). pH- an expression of both acidity and alkalinity on a scale of 1 to 14, with 7 representing neutrality. Numbers greater than 7 indicate alkalinity. Numbers less than 7 indicated acidity. Phosphate-negatively charged, nutrient ion composed of one phosphorous atom and four oxygen -

atoms (PO4 ). Pollution Tolerance Index (PTI)- an estimation of habitat quality based on the presence and absence of bioindicator organisms and tolerance values Pool-(1) a small and rather deep body of usually fresh water (2) a quiet place in a stream Predators- Animals that consume other living organisms Primary Producers- living organisms that produce their own energy from sunlight by photosynthesis (e.g. plants)

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Protein- naturally occurring substances that consist of amino-acid residues joined by pep-tide bonds and contain the elements carbon, hydrogen, nitrogen, oxygen, and occasionally other elements. Riffle- portions of the stream where the flow is slightly turbulent, usually when moving over rocks, where the surface of the water appears to be rippling Scrappers- Organisms with specially designed mouth parts adept to eating algae and other organic materials pressed against other surfaces Shredders- organisms that chew and mine into dead organic material Temperature- degree of hotness or coldness measured on a definite scale (i.e. thermometer) Thermal Inertia-the resistance to temperature change, increasing as the heat capacity and size of a waterbody increases Thermal pollution- significantly heated or cooled water in a natural waterbody at a temperature harmful to the environment; temperate extremes Thermal stress- when an organism goes into a state of shock due to rapidly changing or extreme temperatures, increasing the organism’s risk of further illness Total Solids- In hydrology, dissolved and suspended materials in water Turbidity- a measurement of the clarity of water. It is used as an indication of total suspended solids. Turbulence- the physical churning or movement of water; departure from a smooth flow Water Quality Index (WQI)- an estimation of water quality based on the weighted influence of measured water quality variables

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LESSON 8: FERTILIZER INVESTIGATION OVERVIEW AND OBJECTIVES Learning Objectives Using information from previous class discussions on experimentation, students will develop an investigation of the effects of fertilizer on plants.

Assessment Criteria Investigations will include independent and dependent variables, controls and student hypothesis.

Purpose Students develop an understanding of the effects phosphates on water quality and aquatic plants. The following are multiple options for how the experiments in Lesson 9 and 10 may be enacted. First Option: one experiment (possibly fertilizer effects) is done as a whole class (modeling steps for an experiment) while the other experiment (possibly acid effects) is conducted by small groups. Second option: student groups select one of the two experiments to conduct. Third option: is for the groups to develop their own experiments. Regardless of which option is selected the main goal is to expose students to planning and conducting an experiment over an extended period of time. The material illustrates option 1. This option has the most class supports. The fertilizer experiment is used as a means to model the steps for conducting an investigation. The teacher guides the class through this first investigation, modeling each step as well as providing rationale for design. Working in small groups, students apply what they have learned about designing and conducting investigations as they construct their acid investigations. However, no matter which experiments you choose, each will continue THROUGH Learning Set 3 with students doing observations, recording data and then analyzing the data later in Learning Set 4.

PREPARATION Set-Up See Student Worksheets and be sure to have your materials ready ahead of time.

Special Considerations This lesson, along with the following investigation (Lesson 9) started during this Learning Set, require extended time to collect data. Time needs to be set aside on a regular basis for students to make their observations. You will need to monitor the jars and determine when sufficient data are collected.

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Water will evaporate from the jars or test tubes, Be sure to add additional water that contains the proper acid or fertilizer mixture. Results from these experiments are needed for activities in Learning Set 3

Materials • • • • • •

Ten jars Distilled water Distilled vinegar and lawn fertilizer Duckweed (or other aquatic plant) "?" Investigation Sheets Student Worksheet/What Will Happen? Fertilizer Investigation

Time Two fifty-minute periods.

INSTRUCTIONAL SEQUENCE INTRODUCING THE LESSON Contextualizing the Investigations Make connections with the stream table activities. During the stream table session, students explored how land cover may impact water quality due to the presence of pollution. Specifically, they saw an example featuring fertilizers as non-point source pollution. Students will investigate the effects of two pollutants on aquatic plants. One pollutant will be fertilizer and the other pollutant will be acid rain. Explain that fertilizers contain compounds called phosphates and nitrates. These are the main fertilizer ingredients we will examine.

CONDUCTING THE LESSON Identifying Variables Place the question “What effects do fertilizers (nitrates and phosphates) have on the health of plants?” to be investigated on the board. -Remind the class that nitrates and phosphates are the main ingredients in fertilizer. Hand out Student Worksheet/What will Happen? Fertilizer Investigation Help the class identify the independent variable (you changed it variable). -Show the students the materials and the experimental set-up. Ask the students “What are we trying to find out?” What variable in our investigation are we studying to see if it causes a change or effect? This is called the independent variable and it is the variable we will change. For example, we might use the variable “amount of fertilizer” with three solutions, one which is low fertilizer, a second one that is medium fertilizer and a third one that is high fertilizer.

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Help the class identify the dependent variable (it changed variable). What variable in our investigation are we studying to see if it is affected or changed? This is called the dependent (it changed) variable.

Independent and dependent variables Student understanding is facilitated by experiencing these important ideas in familiar language. Refer to an independent variable as the "you changed it variable" and the dependent variable as the "it changed" variable." As the project progresses, press students to use scientific terms for these concepts.

Model Investigative Process The experiment is designed to provide an opportunity to emphasize the phases of an investigation. The goal is to model the process for composing a hypothesis and identifying the variables. Students are asked to use the process you described as a template for their work in small groups in composing a hypothesis and identify variables for the second experiment.

Rubrics Posting rubrics (evaluation criteria) is one method for supporting student learning. Having students conduct self assessments and peer reviews of their work is another method for supporting students in learning how to learn. By making assessment clear from the beginning, you can help students become more planful and deliberate about their learning. This is the variable that we measure to see if it is affected. Example: In our experiment, plant health is our dependent variable. How can we measure a change in plant health? (i.e. number of leaves, color of plant, height of plant?) Students design a controlled experiment. The simplest form of an experiment manipulates or changes one variable at a time. What variables should remain constant or unchanged (amount of water, number of plants in a jar, amount of sunlight, etc.)? -These variables are called control variables.

Developing an Hypothesis Refocus the class on the investigative question you placed on the board. (What effects do fertilizers have on the health of plants?) Students write their prediction about what will happen to the health of the plants when the amount of fertilizer is increased. Students then share their predictions with the class. Students rewrite their prediction in a proper hypothesis form. If needed, review what makes a good hypothesis with students. For Example: If the amount of fertilizer increases then the color of the plant will become more yellow. Focus the class on the key features of a good hypothesis. Emphasize that a good hypothesis can be supported or rejected by data.

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Procedure Focus the class on the materials used for the experiment. Demonstrate the set up for the students and have them follow along. Check for student understanding.

Making Observations Discuss with the class how to make quality observations. -What will they observe? -How often will the observations be made? -How can we organize our data? Guide the class to record the following in their observations: -Record the data. -Write a description indicating the size and color of the plant. -Students should draw their observations as well. Determine with the class when and how frequently observations will be made. Be sure observations are made at the start of the investigation. It is useful to post the schedule for observations some where in the room

CONCLUDING THE LESSON Class reviews hypothesis. Students record initial observations. Review when future observations will be done.

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LESSON 9: PH INVESTIGATION OVERVIEW AND OBJECTIVES Learning Objectives Using information from previous class discussions on experimentation, students will develop an investigation of the effects of pH on plants.

Assessment Criteria Investigations will include independent and dependent variables, controls, and student hypothesis.

Purpose Students explore the effects of acid on water quality.

PREPARATION Materials • • • • •

Ten jars Distilled water Distilled vinegar and lawn fertilizer Duckweed (or other aquatic plant) Student Worksheet/What Will Happen? Acid Investigation

Time One fifty-minute period.

INSTRUCTIONAL SEQUENCE INTRODUCING THE LESSON As a class, review the variables for the investigation. Independent (you changed it) Variable: something you changed e.g. amount of fertilizer Dependent (it changed) Variable: something measurable e.g. amount or health of the duckweed (number of leaves, and/or color) Control Variables: things kept the same, e.g. size of container, type of plant, amount of light, etc.

CONDUCTING THE LESSON Ask the class if they remember any sources of acid rain and if they are present in our community. Pose to the class the question “What effects will acid have on plants?” Discuss with the class what they know about acid rain and how it might affect plants.

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Explain to the class that they will do a similar investigation as the fertilizer experiment except this time we will use different amounts of acid. The acid simulates the affects of acid rain.

Identifying the Variables Students take out their Student Worksheet/What Will Happen? Acid Investigation. Place the question (What effects will acid have on plants?) to be investigated on the board. Inform the class that pH is a measure of acids and bases. -Review the pH scale. A low pH indicates a strong acid while a high pH indicates a base. Water is neutral at a pH of 7.0. Help the class identify the independent variable (you changed it variable). Show the students the materials and the experimental set-up. Ask the students what questions they are trying to answer. What variable in the investigation are they studying to see if it causes a change? Students work in groups to identify the variables in the experimental set-up, the independent, dependent, and control variables. Remind the students to think about how the experimental set-up will help answer the question. Monitor students’ work and decide if a full class discussion is necessary or collect the work and offer students feedback so they can refine their work for home session.

Developing a Hypothesis Prompt students to reflect about what they already know about pH (acids and bases) and then to think about how acid will affect the health of the plants. Students write a hypothesis individually, then share in pairs to rework their hypothesis. Remind students of the key features of a hypothesis. Walk around the class monitoring the students’ work. Based on your monitoring, decide if the entire class needs to work through the hypothesis again. Alternatively, collect the work and offer students feedback to refine their next hypothesis.

Procedure Focus the class on the materials used for the experiment. Assess if the students are able to go forth with the set up themselves

Making Observations Review what makes good observations, how often to make the observations, and how students can organize their observations. Students should -Record the data. -Write a description indicating the size and color of the plant. Draw their observations of the plant.

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Determine with the class when and how frequently observations will be made. Be sure observations are made at the start of the investigation.

Start the pH Investigation As a group review the variables for the investigation. Independent (you changed it) Variable: amount of acid Dependent (it changed) Variable: amount or health of the duckweed (# of weeds, and/or color) Control Variables: size of container, type of plant, amount of light, amount of fertilizer, etc.

CONCLUDING THE LESSON Have groups record initial observations with the class. Review when future observations will be done.

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LESSON 10: VARIABLES AFFECTING WATER QUALITY OVERVIEW AND OBJECTIVES Learning Objectives Using ideas generated in class and manipulatory oxygen probes, students explain how new variables affect water quality.

Assessment Criteria The variables affecting water quality will include, total solids, turbidity, fecal coliform and dissolved oxygen. Student explanations will include how each variable affects both plant and animal life.

Purpose Students learn about and test for the various chemical and physical variables that affect water quality. • • • • • •

Variables introduced in this session include: Total Solids Turbidity Fecal coliform Dissolved Oxygen Biological Oxygen Demand

Set aside 5 -10 minutes each day for students to continue making observations of their experiments. This can either be done at the beginning or end of the class period.

PREPARATION Set-up Teacher should review experiments, create notes of their interpretation and experiment with computer probes

Materials • • • • •

Water Quality Jars Flashlight Four Water samples of various temperatures Dissolved oxygen probes Student Reader/Testing Your Water

Time Two fifty-minute periods. Don’t forget to provide students time to make their experimental observations.

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INSTRUCTIONAL SEQUENCE - Day 1 INTRODUCING THE LESSON What are some investigations that we have recently conducted hat might effect water quality? • • •

Fertilizer (containing Nitrates and Phosphates) Acids (pH) Soils (erosion and deposition)

Discuss with the class some substances that might be found in our river, for example, “if you used a strainer in our river what might you find?” or “ if we took a bucket of water from our river what would we find in the bucket other than just clear water?” How might substances get into the water? Reflect back to the stream table activity. Focus the students on the concepts of: • Run-off, which can create non-point source pollution • Combined sewer overflows, a point source pollution • Erosion Deposition Affects of land cover and use Based upon our experiments, models, walks, and videos, what are some possible effects of these substances being in the water? • • • • •

Fertilizer – increase in plant (algae) growth pH - decrease in plant growth (less food and habitat) pH - decrease in biodiversity (some organisms can only live in neutral water) Soil- murkyness, plants decrease, block up some organism’s gills Sewage- increase algae and bacteria and poison organisms

Have students (either as whole groups or one per group) select one of the terms below and read the appropriate sections in the reader and answer the questions at the end of their section to present to the class. • • •

Total Solids Turbidity Fecal Coliform

Establishing links to the Driving Question Facilitate connection to the driving question. This may be accomplished by revisiting past activities (river tank, water jars, virtual tour/video or walk) and asking probing questions such as: • • • • •

What is the turbidity of the water? Was the river murky? Was there a lot of "stuff" suspended floating in the water? Do you think that the river absorbs a lot of light? Do you think that there is a high or low amount of total solids in the river? Why?

CONDUCTING THE LESSON Retrieve the water quality sample jars used at the beginning of the project. These jars can be used as examples of turbidity and total solids. Turn off lights and shine the light through the turbit, and clear jars. If time permits create a jar with solids in it, use sand or twigs.

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Ask students how plants would grow in each? How would the solids in the water affect plants and organisms? What might cause the material to get into the water? -Have you ever seen a river that looks like the murky jar? Ask the students how might we prevent water from having high turbidity, high total solids or high levels of fecal coliform? (Optional- in groups, have students come up with measures or ways humans can prevent rivers from having unnaturally high levels of the variables listed above. Discuss what local communities and students can do to prevent pollution in water ways.)

CONCLUDING THE LESSON Using new concepts have students answer either as an exit question or in their journals: -How do total solids and turbidity affect how much light penetrates the water? -How do total solids and turbidity affect the temperature of the water? • • •

How does Fecal Coliform get into the water? What are some measures we can take to prevent high turbity, total solids and fecal coliform from getting in the water? How do you think total solids and turbidity impact the quality of the water?

HOMEWORK Assign the Student Reader/Testing Your Water.

INSTRUCTIONAL SEQUENCE Day 2 (Cont.) INTRODUCING THE LESSON Ask class to describe water quality variables identified yesterday. -What are these variables? (Turbidity, total solids, fecal coliform) -How do they get in to the water? -What are some of their effects? •

Go over questions from Student Reader/Testing Your Water.

CONDUCTING THE LESSON Transition the class by explaining that today we will continue our talk about substances in the water that affect water quality. Ask the class what do fish and humans have in common? (They both breath air.) How do fish breath under water, where do they get oxygen? Introduce the following terms by either writing them on the board or at student tables. Dissolved oxygen Biological oxygen demand Explain why DO is necessary for aquatic life. • •

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Guide the class through the difference between dissolved oxygen and the oxygen atom found in the water molecule. -Can someone describe the chemical formula for water? -If we could use a really powerful microscope to see molecules, what would oxygen dissolved in water look like? -Emphasize that the oxygen molecule is a different and separate than the compound water.

(Optional Activity) Using ball and stick models or gumdrop models to illustrate the mixture of water and oxygen will reinforce the difference between dissolved oxygen and the oxygen atom in the water molecule. Using these models, place ten to twelve water molecules and 3 or 4 oxygen molecules in a container to represent the dissolved oxygen mixture.

Relationship Between Temperature and DO In front of the room, set up four different glasses of water of differing temperatures (ie: from very cold, cold, room temperature, and hot.) Set up the dissolved oxygen and temperature probes on a computer along with a method for displaying. Review with your students molecular motion and change in energy levels with change in state of matter (solid:molecules barely move and are close together, liquids: some movement and molecules are farther apart, gas: molecules move fast and are as far apart) -when heat is added molecules move faster and farther apart when heat is taken away, or made cooler, molecules slow down and come closer together when water is cold, oxygen slows down and can be closer together, where as when it heats up oxygen will move faster and want to be farther apart. Cold water can then hold more dissolved oxygen than warm water. Have the class make a hypothesis on which water jar will have the highest dissolved oxygen. Use the probes to measure dissolved oxygen and temperature. Start with the coldest jar and move to the hottest jar. Prompt the students to note the results on the computer screen. Hold a brief class discussion on the results and have students record in their notebook.

Relationship Between Amount of Stirring and DO. Maintain set-up and select the jar at room temperature. Record the DO to start which will serve as the baseline. As you are waiting have the students set up their graphs in their journal to record the various levels of DO Vigorously stir water and then record DO. Ask students when would a river be stirred up like the water in the jar? Prompt students to suggest rapid streams, after a storm, streams with many rocks and boulders and mountain streams.

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DO might be difficult for students to comprehend especially the relationship between temperature and levels of DO. Share with students examples they might be familiar to help students make this concept relevant. For example, the most abundant fish populations come from the depths of the cold Atlantic and Pacific oceans. Many organisms can’t live where companies dump warm waste water back into rivers. Blue ribbon trout streams are usually very cold and have abundant amounts of oxygen. Discuss with students whether stirring or water being tumbled around is good for organisms. See side bar, for example you can mention many good fishing streams have much mixing of the water, or why storms are important to lakes, so that the water can be mixed and oxygen added. Hold a brief class discussion on the results and have students record the data in their journal or in a graph.

CONCLUDING THE LESSON Pose the following questions to students in a classroom discussion: • • • • •

How do these demonstrations relate to an actual river and to our river? What affects the amount of dissolved oxygen? Is water with low amounts of oxygen good quality water? How is dissolved oxygen used? Where does the oxygen come from?

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LESSON 11: REVISITING THE PH AND FERTILIZER INVESTIGATIONS OVERVIEW AND OBJECTIVES Learning Objectives Using data from their investigation students will formulate a conclusions to their experiments.

Assessment Criteria Conclusions will be based on and supported by data and meet the guidelines for a good conclusion (see below).

Purpose Students analyze their data and construct conclusions for the “Fertilizer and pH” investigations. Class discussions facilitate student reflection concerning the various project activities and how they connect to the driving question. These guided discussions introduce students to the other variables that affect water quality, how these substances might get into the river and their possible environmental effects.

PREPARATION Special Considerations If experiments have not shown significant change, add to the computer model first, then re-evaluate experiments.

Materials • •

Retrieve experiment - test tube or jars Optional graphing paper

Time One fifty-minute period.

INSTRUCTIONAL SEQUENCE INTRODUCING THE LESSON Review with the class the key aspects of the investigation -Purpose -Hypothesis -Procedure Have students retrieve experiment (test tubes or jars).

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CONDUCTING THE LESSON Analyzing Data As a class have students take a look at their data noticing any patterns or trends they can find in their observations. (Optional-Hand out graphing paper) Have students work in groups to graph their data and answer the following questions: -How does the amount of fertilizer (causal, independent variable) affect the growth of the duckweed (dependent variable)? -What evidence in your observations support your statement? -Was your hypothesis supported or not supported? Have students discuss the group questions: Ask for individual groups to share their interpretation of the data. As a class, discuss findings. Have groups call on each other to compare results.

Conclusion (Suggested Rubric Guidelines) Support the class in composing a proper conclusion. A good conclusion has: (either write on the board or hand out rubric) • • • • • •

A description of the purpose of the investigation. A statement of your hypothesis. A statement describing if your hypothesis was supported or not supported by your data. Evidence (observations and data) which links to either support or disprove your hypothesis. A statement of how the investigation relates to the driving question. What you would do to improve the investigation, or what other questions has this investigation caused you to think about?

Work with the students through the above process to build their conclusion. Use student observations and probing questions to facilitate the conclusion building process. If students are having difficulties, post 2 different conclusions: one excellent and one sub par to demonstrate a good conclusion and a not so good conclusion, and have students identify the correct and incorrect aspects in each.

CONCLUDING THE LESSON • • • •

Review with the class the key features of a conclusion. Student volunteers share conclusions. Class assesses conclusions using conclusion rubrics. Provide student opportunity to revise.

HOMEWORK Students work on their pH conclusion for home session. Class offers feedback the next day so students can revise their conclusions.

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LESSON 12: WATER QUALITY TESTING OVERVIEW AND OBJECTIVES Learning Objectives Using the water quality test kits and equipment, students will become adept at measuring water quality variables. (lab skills).

Assessment Criteria Students will be proficient using water quality tests and equipment.

Purpose During this lesson, students test the variables they have been studying on river water samples. There are two options for testing river water: • •

Take a trip to your river and conduct water tests the field. Teacher obtains local water samples and students complete water tests in class. (Create a teacher video if feasible.)

Working in groups, students perform five water quality tests on water samples from their river. Students perform the tests for nitrates, phosphates, fecal coliform, turbidity, and pH while the teacher performs DO, BOD, and temperature tests at the time of the water sampling from the river. The water quality of their local river, based on each individual test, is ranked on a scale of excellent to poor (4-1).

PREPARATION Special Considerations Read through preparation in the Appendix and familiarize yourself with each test. Make sure you are comfortable with how each test works in order to answer student questions on procedures.

Materials • • • •

1-5 gallon bucket of river water. (Optional)Video of water sampling. Low Cost Water Quality Monitoring Kits Student Worksheet/Water Testing

Time Two fifty minute periods.

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INSTRUCTIONAL SEQUENCE INTRODUCING THE LESSON Review and discuss with students the variables they have been investigating that affect water quality, prompt them to reflect on their computer models (ie. dissolved oxygen, fecal coliform, nitrates, phosphates, etc.) Inform the students that now that they are familiar with what affects water quality it is time to test their river’s water quality. Briefly introduce the final water quality testing methods, which will depend on which water quality test kit you obtain.

CONDUCTING THE LESSON Construct a prediction Individually have students review their conclusions from previous direct water quality measuring activities (e.g. River Walk, Is it Drinkable?) Based upon their conclusions from these activities have the students construct a prediction for water quality of the river based upon the chemical tests that they will complete.

Setting Up the Task At this point if you are going to the river you’ll want to give your students more specific directions as to who will be responsible for what materials, observations, data recording, etc.. Either way, be sure to demonstrate and have students practice the water testing techniques before you go to the river. •

After the students have completed their predictions, demonstrate in greater detail the testing kit materials and the general procedure to the testing series: nitrates, phosphates, pH, fecal coliform, temperature, dissolved oxygen, BOD, turbidity, and total solids.

Hand out Student Worksheet/Water Testing •

Within groups students decide who will perform each test -The name of the person performing the test is placed next to the name of the test on the River Testing packet. -Everyone should have an opportunity to perform at least one test

Teacher checks to see if groups have distributed testing roles.(be sure you have enough directions to distribute, make extras if needed) . Student testers review their specific test procedure(s). Teacher determines if groups are ready to test water.

Testing the River Water Working in groups, students perform the series of water quality tests. Teacher walks around room monitoring student activity. Students record data in their investigation packets, journals or on worksheet sheets.

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CONCLUDING THE LESSON When groups have completed testing, have them clean up. Support students in sharing data. This may be facilitated by using a classroom chart. An example chart may include: -rows for each water quality test -columns for each group to place the results allow one column for class average

Final Testing Groups share data and record it on the classroom chart. Have students give a summary of the variable they were testing. Have students copy classroom chart.

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LESSON 13: ANALYZING WATER QUALITY TESTS AND MAKING CONCLUSIONS OVERVIEW AND OBJECTIVES Learning Objectives Using data collected from the water quality tests, students will analyze the classes results and draw conclusions.

Assessment Criteria Student’s analysis will be based on the class average and will include accurate ranking of each test on a scale of 1- 4. 4 being excellent, 1 being poor.

Purpose Student will analyze, interpret and draw conclusion from their data as to the quality of water in their local river.

PREPARATION Special Considerations Read through preparation in the Appendix and familiarize yourself with each test. Make sure you are comfortable with how each test works in order to answer student questions on procedures.

Materials •

Student notes, worksheets or observations from water testing.

Time One fifty minute period.

INSTRUCTIONAL SEQUENCE INTRODUCING THE LESSON Review the collected data. -Place classroom chart on overhead -Review with students the various tests they conducted -Ask students why they think we have a class average column on the chart. Explain that this helps us to be more scientific ally accurate. For example, you can ask the students if the teacher only picked one student’s grades to represent that of the who class, would that be very accurate of all students’ grades? No, you would take the average of the class. This is why we take an average of the water tests, one group might have not done the procedure correctly or misread the instrument.

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CONDUCTING THE LESSON Making Meaning of the data collected Place an overhead of the Physical and Chemical Test Ranking Chart up in front of the class (if one is not included make one from the information in your water testing kit). In most kits, these can be found at the end of the booklet describing the procedures for water testing. Student results from yesterdays test are ranked on a quantitative scale of 1-4. 1 being poor, 4 being excellent. Model how the students will use their readings to determine the proper ranking number, 1-4. Then have the students work in their groups to rank each test on the scale of 1-4. Teacher checks for student understanding. Groups share rankings for each test -Peers discuss and class consensus is reached

Calculating Overall Water Quality Ranking Explain to the class that each variable we tested affects water quality differently. Some variables are more important or have a larger impact than other variables. Each test has a weighing variable which indicates how important the factor is in determining the overall water quality. For example, some organisms can are better adapted to handle total solids in the water (weighted .08) or levels of nitrates (weighted .10) but can not withstand much drop in dissolved oxygen (weighted .17). Different organisms adapt in different ways to handle various water quality variables. We will learn about such organisms in the next lesson. Teacher places a copy of the weighted water quality chart in front of the class. Class discusses the meaning of the weights. -Look at the weighting variable. Are they all the same? Are they different? How are they different? • •

•

•

If the weighting variable for DO is .17 and the weighting variable for total solids is .07. What does this tell you about how important each variable is in determining water quality? Calculating the overall water quality ranking: (calculators are helpful but not necessary) Model how each ranking is weighted for example, BOD and temperature. (This can be very confusing for student ) Multiply the ranking value for DO by its weighting variable and record the product. Have each group do the remaining weighting of each variable. Students should record their results on their sheets. -Have the groups calculate the overall water quality ranking by adding the weighted rankings and recording the result on their data sheets. Have the students compare the overall water quality ranking to the following scale and record their result.

Make sure the students wrote down their totals. Explain that what they did is very similar to what scientist do when monitoring the quality or various streams and river.

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Preparing to Write the Conclusion •

•

• • •

Review with the students what should be in their conclusion. Key ideas may include: -Review criteria for a quality conclusion -Focus student attention upon the previously posted conclusion rubric Add one additional criteria to the conclusion: “How does our results from this series of water quality tests compare with the results from our previous tests? (River Walk Observation, Is it Drinkable Observation) Conclusion criteria: -Make a claim related to your hypothesis -Provide evidence to support your claim: use data you have collected Write your claim clearly. It needs to be a complete thought, and written in precise scientific language. Anyone who picks this up should be able to understand what you write. Students write a statement of error or limitations for their experiment.

CONCLUDING THE LESSON Writing Conclusion Have individual students write a conclusion. Have students share conclusions with two to three peers. Peers offers feedback based upon the rubric. Students revise conclusions.

HOMEWORK If students have access to computers have them do a web search for stream monitoring sites and have the students compare what they did and their procedures with what they found on various websites.

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LESSON 14: BIOINDICATORS OVERVIEW AND OBJECTIVES Learning Objectives Using ideas generated in class and possible collecting of organisms, students will describe which macroinvertebrates are indicators of water quality.

Assessment Criteria Student descriptions will include the ideas of pollution tolerance and sensitivity, habitat requirements and biodiversity.

Purpose During this lesson, students use the biodiversity of aquatic organisms as an additional method to determine water quality in their local river. The collected organisms are identified and sorted by the students. The results are then analyzed and conclusions are made about water quality.

PREPARATION Special Considerations Prepare an aerated water tank in the classroom for keeping live benthics a before collection organisms, make sure there are many hiding places in the tank, some organisms will prey on others. Student permission slips will be needed if going to the river. Teacher will have to decide between taking a sampling trip to the river with the class, or collecting the samples a head of time. Have materials prepared for the option you choose. Have the sorting kits already set up or together before the students get into groups. Read through Macroinvertebrate Identification and Sorting Guide Sheets to familiarize yourself with the process of sorting and ranking.

Materials • • • • • •

Aquarium tank for housing the collected organisms in the classroom D frame collecting nets, or other dip nets jars or containers to keep organisms in while traveling gloves and goggles waders (optional) Sorting kit, each containing the following: -ice cube trays or 14 petri dishes -spoons, forceps and turkey baster -magnifying glass -gloves and goggles -large shallow light colored pan Student Worksheet/Macroinvertebrate Identification and Sorting

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Time Two fifty minute periods.

Anchoring Experience Examining the living organisms in their river connects students to the river in their community. Students should reflect back on the observations they made during the river walk, video, and/or virtual tour.

Option ONE Taking the students on the sampling trip will bring the students closer to their river.

Option TWO Although not as exciting as participating in the sampling, a video of the sampling will bring closer to their river and the activity.

INSTRUCTIONAL SEQUENCE INTRODUCING THE LESSON Review with the class the previously developed definitions for water quality and some of the water quality testing methods they discussed at the end of the previous session. Inform students that an additional method for testing water quality is doing an investigation using organisms that live in the river as indicators of water quality

CONDUCTING THE LESSON Macroinvertebrates Prompt students to brainstorm responses to the following questions. -What types of organisms live in and around the water? -Why would these animals be important? -What do living things need to survive? Introduce the term “Macroinvertebrate” and explain that this group of ‘bugs” is an indicator of water quality. Explain that these “bugs”, macroinvertebrates play a key role in stream health and and as indicators of water quality because they differ in their ability to tolerate pollution. Some are tolerant of pollution and others are not. Further explain that many macroinvertebrates live along the sides and bottom of streams and rivers. Since each type has a different degree or tolerance for pollution, their presence or absence can be an indication of the quality or health of the river or stream. -Discuss the important role of macroinvertebrates at the base of the food chain for other organisms in the river ecosystems, and that they make up a good part of the biodiversity in rivers

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Discuss with the class the concepts of "biodiversity" and why it is important for not only rivers but all natural areas to have bio diversity.

Student Investigation • • •

Ask your students to think back to their river walk. Did they see any signs of biodiversity? Ask for examples? Could we tell by looking at the river if there were any macroinvertebrates? -How might we find out if there are any in our river?

Prompt the students to respond that they need to do an investigation. Inform the students that they will be conducting an investigation of the macroinvertebrates in their river. Have students make hypothesis and predictions regarding what biodiversity they think they will find.

Preparing to Collect the Organisms Before the organisms are collected the teacher must decide how the collection is to be conducted. There are two options 1) the teacher does the collection or 2) the students do the collecting. Describe for the class the several different sampling locations (river bottom, bank, in vegetation, and under rocks). Ask students why several different locations are sampled (to obtain a larger and more diverse sample. If students are collecting the organisms then a description of the collecting procedures needs to be completed. Additionally, you will need to go over safety rules for conduct at the river. Review with the class the collection procedures, transportation and containers for the organisms. Assign roles and responsibility ties for the students while they are on their collection trip. Describe and/or demonstrate the collection equipment. The D-frame net is a simple way of collecting benthic macro-invertebrates. The D- frame net is design so that the flat area at the front of the net can be placed at the bottom of the river reducing the loss of organisms underneath the net. You can use this net to collect samples from the bottom of the river as well as along the banks of the river and in vegetation. WEARING GLOVES AT ALL TIMES Discuss the proper procedure for handling the macroinveterbrates from the net to the containers. Possible Alterations One possible extension to this activity is to have students compare the different sampling locations. • • • •

Have the students make predictions about the organisms from these different locations Will they be similar or different? Why? Will they have special adaptations? What kinds? Have students record predictions and rationale.

Biodiversity refers to the range of organisms present in a given location. When pollution changes environmental conditions, some organisms can not survive. A few organisms can tolerate a range of conditions. Therefore the more different types of organisms that are found, the less pollution there is.

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Contextualization If organisms were collected by the teacher, show a video tape or other method to indicate where the organisms came from.

Methods of Collecting There are multiple methods of collecting benthic macroinvertebrates. For other methods of collection, see the Field Manual for Water Quality Monitoring by GREEN.

Gloves and Goggles If students will be participating on the collection of the organisms, students should wear gloves and goggles. If you have waders then this activity is best done in the water. If you do not have waders then you can still get some sampling done from the bank of the river. Either from within the river or from the bank, place the net at the downstream side of the sampling area with the opening facing upstream. Hold the net perpendicular to the flow and as close to the bottom of the river as possible depending on your position. Hold the net for a short period of time. After good flow has moved through the net. Take the net out and place what ever you collected in a large bucket with some water in it. Repeat the sampling until you have collected a large enough sample for your classes with which to work. If you are able to go into the river and have some assistance, sample again with the net. Hold the net close to the bottom of the river as you did before, but this time have your partner stand three feet in front of the net and twist their feet into the bottom of the river. This action will free sediment from the river bottom and dislodge more macro invertebrates.

Bank of River Walk along the bank of the river. Choose an area along the bank and simply place the net along the side of the bank with the opening of the net facing upstream. Rub the net along the side of the bank disturbing any sediment. Hold the net for a short period of time. After good flow has moved through the net. Take the net out and place whatever you collected in a large bucket with some water in it. Repeat the sampling until you have collected a large enough sample for your classes with which to work..

In Vegetation Choose an area that has a large amount of vegetation. Place the net in the water by the vegetation so that the opening faces upstream. Firmly rub/brush the vegetation with the net, disturbing any organisms that may be hiding or attached to the vegetation. Move the net up and down and side to side.

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Hold the net for a short period of time. After good flow has moved through the net. Take the net out and place whatever you collected in a large bucket with some water in it. Repeat the sampling until you have collected a large enough sample for your classes to work with.

Under Rocks Wearing gloves, pick up any stones or rocks greater than 2" in diameter. Rub it to remove any organisms that may be present and place them in the collecting bucket.

Upon Return Upon returning from the collection, place the organisms into a previously prepared river tank. Habitat Comparison Option: (Optional- Several tanks may be utilized if the teacher wishes to have separate tanks for different collection locations. This option allows for students to make comparisons between the organisms of different locations)

Setting up the class Break students into groups. Provide each group with an Identification and Sorting guide and a sorting kit, and a large pan with Macroinvertebrates. Teacher models the process first, followed by the students. Using their identification and Sorting guides students count each different type of organism in each group (one, two, and three). Students place a check mark next to each type of macroinvertebrate found. Teacher monitors the progress of the groups.

Checking Student Results and Sharing Data When most groups have completed the activity, the teacher leads the class in a brief sharing of their data. Teacher uses overhead or large chart and asks groups to identify one organism they found. Ask other groups if anyone else counted the organism. If agreement, mark on class chart. Repeat steps with the next group or organism.

Sorting To facilitate the identification and sorting,you can use two methods: Write the name of each type of organism at the bottom of each compartment of the tray so as students sort they can also identify them one by one.

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Biotic Index for Sample Is an index that indicates water quality based on the pollution tolerance of macroinvertebrates

Identification and Sorting Biting Organisms Caution students that some organisms may pinch or bite. They should be handled with spoons or tweezers. Wearing goggles will keep river water from being splashed into student’s eyes. Wearing Gloves will protect students from any pathogens in the water. Students should wash their hands with a disinfectant soap after handling the Organisms.

What is the Water Like in Our River?





Learning Set 3 - Page 94

LESSON 15: WHAT DO ORGANISMS TELL US? OVERVIEW AND OBJECTIVES Learning Objectives Using data from collecting macroinvertebrates or teacher given data, students will analyze and make a conclusion about the quality off water in their river.

Assessment Criteria Conclusions will be based on the “good conclusion” rubric utilized throughout the unit, and will include the data from the macroinvertebrate collection.

Purpose Students use the results from the collection of macro invertebrates or teacher data re analyzed an conclusions are made about water quality.

PREPARATION Set-up •

See EPA Website on Bioindicators

Materials •

Refer to Lesson 14 for this Student Worksheet/Macroinvertebrate Sorting and Identification

Time One fifty minute period.

Biodiversity refers to the range of organisms present in a given location. When pollution changes environmental conditions, some organisms can not survive. A few organisms can tolerate a range of conditions. Therefore the more different types of organisms that are found, the less pollution there is.

INSTRUCTIONAL SEQUENCE INTRODUCING THE LESSON Using their Pollution Tolerance Index sheet students analyze their data. When each group of benthics have been multiplied, the sum of all three groups is calculated and placed in the appropriate box on the data sheet.

What is the Water Like in Our River?





Learning Set 3 - Page 95

Students then take their total and rank the quality of water based on the scale provided. Students circle the corresponding water quality ranking. Have each group give their biotic index and list them on the board and then take an average of all the groups to create a final biotic index.

CONDUCTING THE LESSON Drawing Conclusions Work with the students to think about what conclusions they can draw about the relationship between the number of different organisms and water quality. Connect the discussion to the Driving Question. • • • • • •

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The discussion may be focused by utilizing the following questions: How many different types of organisms did you identify in your sample? Did you identify macroinvertebrates with high pollution tolerance values ? What does this tell you about the water quality? Did you identify macroinvertebrates with low pollution tolerance values ? What does this tell you about the water quality? Explain. Does your sample show a lot or a little biodiversity? Explain. What did your data say about the quality of the water in our river? What would the water quality be if you had a larger number of different types of macroinvertebrates?... or a smaller number? How do you think biodiversity is related to water quality?

Writing Conclusions Review with the students what should be in their conclusion. Handout Conclusion worksheets Review criteria for a quality conclusion. Focus student attention upon the previously posted conclusion rubric. Add one additional criteria to the conclusion: “How does our results from this series of water quality tests compare with the results from our previous tests? (River Walk Observation, Is it Drinkable Observation) Conclusion criteria: • • • •

1. Make a claim 2. Provide evidence to support your claim: use data you’ve collected in the experiment 3. Write your claim clearly: It needs to be a complete thought, and written in a precise scientific language. Anyone who picks this up should be able to understand what you write 4. Students write a statement of error or limitations.

CONCLUDING THE LESSON •

If time permits allow students to turn in their draft conclusions for feed back and revisions

What is the Water Like in Our River?





Learning Set 3 - Page 96