Evaluating Water Quality by Counting Critters
Developed by: Jo Naegeli (Middle School Science), Carol Murabito (HS Aquatic Science Class), Kenneth Schneider (HS Agriscience Class) Rogers ISD

Macroinvertebrates are excellent indicators of water quality. They live much of their life cycle in the same area of a stream or lake. This unit demonstrates how to collect stream debris samples, locate, identify and sort Macroinvertebrates within the samples, and evaluate water quality based on species diversity and population.

Connection to the Curriculum

Students from HS Aquatic Science Class, HS Agriscience Class and Sixth & Seventh Grade Science Classes will gain understanding of the causes of water quality problems, as well as potential solutions.

This will be an on going project throughout the first semester. Initial class time to locate sites with Satellite Navigator, map sites, photograph sites, collect first samples will be 3-4 HS class periods of 55 minutes each & 3-4 Middle School class periods of 90 minutes each. Sorting and classifying organisms will involve all age students in their teams and individual classes. Several joint classes, HS plus MS are scheduled to allow mixed age groups to work together on their group assignments. Selected sites will be monitored once a month there after until the end of the project.

Project could be done any time of the year.

1. aquatic sampling nets
2. plastic dishpans
3. forceps
4. medicine dropper or kitchen baster
5. sorting trays
6. microscopes, Discovery Scopes and hand lens magnifier
7. laminated macroinvertebrate ID sheets "The Bug Sheet"
8. recording sheets
9. pencils
10. large washtub or buckets
11. Aquarium or jars to keep large samples in classroom
12. Stream Study: Sample Record and Assessment
13. Guide to Macroinvertebrates as Indicators or Water Quality Conditions

1. Satellite Navigator
2. Digital Camera
3. Scanner
4. CD-Rewriter
5. Internet Search
6. Teleconference Participation
7. Power Point Presentation
8. E-mail
9. Data Base

Objectives

1. 1. Collect stream debris samples from suitable habitats
2. 2. Locate and identify Macroinvertebrates in the samples
3. 3. Evaluate water quality based on species diversity and population
4. 4. Understand basic causes and significance of water quality problems along with potential solutions
5. Operate the Satellite Navigator – to read & map original site & to return to site for future samplings.
6. Operate a Digital Camera - to record the appearance of site on each sampling trip.
7. Work together in small multigrade level groups – 2 HS students with 2-4 MS students
8. Support fieldwork with research in library and on the internet.
9. Evaluate water quality based on chemical tests of water samples

1. Instructors and guest speaker present Water Monitoring Project to students in individual classes by grade level and in the field to all participating grade levels. Emphasis can be placed on the experimental nature of project because leader usually does not know what the results will be. Even if sampling has been previously done on the same stream conditions could have changed between tests. Basic environmental aspects can be presented now or held until after sampling and analysis is complete.
2. Students use internet to research "Water Quality Factors", Sampling Procedures, Chemical Testing Methods, Local Water Shed Maps & Monitoring Sites, Macroinvertebrates as Water Quality Indicators. (All students in grade level and mixed group.)
3. Sampling procedure with nets and other equipment is demonstrated on land then reviewed at the water. High School Students are taught on the first trip to Salado Creek. HS students are divided into groups of 2 and are assigned 2-4 sixth and seventh grade students. The HS students will act as teachers and team leaders responsible for the completion of the groups’ assignment.
4. Different habitat types should be pointed out and described, including:

• vegetated margins and banks
• silty substrates with organic debris
• sandy/gravel bottoms
• woody debris with associated leaves, algae and fungi

    5. Each habitat type should be sampled according to the following procedures. In each case, be sure to           look at the inside of the net after dumping a sample into the dishpan. Many of the invertebrates can be           found clinging to the netting.

Vegetated margins and banks should be vigorously scooped from the bottom up, starting 2-3 feet down and finishing at the surface. Sand, silt, mud and vegetation should be retained in the net with water allowed to drain away. This should be done for approximately 10 feet of stream bank, working upstream. Retain this sample in one pan or divide among several if needed.  Record what type of sample is in each pan. This area will usually have a good diversity of several macroinvertebrates types particularly mayflies, stoneflies, dragon flies, and damselflies. In slow streams, lakes and ponds vegetation may be the best location to find suitable habitat and Macroinvertebrates, especially dragon flies and damselflies, but also scuds and sowbugs. Woody debris should be collected from any area of the water body  where it can be found. Debris piles should be approached from downstream with the sampling net held below and downstream while leaves and other loose items are pulled into the net. Small pieces of wood approximately 3 inches in diameter should be collected until you have a total of 4 or 5 feet of wood. Retain samples in one or more pans and label sample type. Like stream banks, woody debris is usually a good place to sample, especially in slow streams. Look for mayflies, stoneflies and beetle larvae, but large dragonflies can be prowling for other insects and caddisflies can be found filtering the water with tiny nets. Again, like stream banks, this is a good source for quick and easy sampling.

Sandy/gravel bottoms in still water can be sampled by vigorously scooping substrate from the bottom. Move the net approximately three feet across the bottom trying to dig in 1-2 inches. In moving water, scoop as before working upstream so organisms are swept into the net or position the net downstream of a 3-foot  sampling area and kick around in the sand and gravel to disturb the substrate and force organisms up into the current. Retain sample as before. This area is not as productive as the previous two locations, but you can find midges, clams, swimming mayflies and very interesting case-building caddisflies.

Silty substrates are found where current is very slow or absent. Samples can be collected as described under sandy/gravel bottoms. This is usually the least productive area, but you may find burrowing mayflies if enough oxygen is present. This is an important area to check for the adequacy of oxygen levels in the stream or pond because this will usually be a low oxygen area. If mayflies are found here the oxygen level in the rest of the water body should be very good.

It is important to try and sample all of the habitat types in order to be most accurate. With comparisons being made between two or more different sites, it is important to sample the same habitat types, with the same intensity, in each water body.

6. Collected Samples are divided into dishpans, with teams sorting through their samples. Instructors and students review the characteristics of the creatures they will identify. Scuds and beetle larvae will usually be on the small side; mayflies and stoneflies are usually about 1/4 - 1/2 inch, while dragonflies and damselflies are usually the largest thing found. However, hellgrammites and craneflies can both be very large but are rarely found.

Sorting should be done by removing small portions of the debris, one or two leaves at a time, and looking it over closely. Forceps or medicine droppers can be used to pick-up smaller organisms. Woody debris should be scanned carefully on the surface and then loose pieces broken away to find mayflies, stoneflies and caddisflies which hide in crevices. Most of the organisms will be brown or black and blend in very well with their surroundings. In green vegetation, damselflies will frequently be green and just as hard to see. Look for movement to give the creatures away. Water should be kept to a minimum in the pans because it is usually murky, however, if the water is clear enough macroinvertebrates can usually be seen swimming around in the bottom. For this reason, any water present in a pan should be kept as calm as possible to avoid stirring up the mud.

As organisms are located they should be separated into look-alike groups by placing them in individual cells of an ice cube trays or egg cartons. Students will use Macroinvertebtrate Identification Sheet to aid identification. Microscopes or hand lens can be used to help identification or observe behaviors. Ice cube or egg carton cells should be filled with clear stream water so that the organisms can be seen and counted, ie. all dragon flies should go in one cell, all mayflies in another, etc. There are 2 reasons for this: one, dragon flies, damselflies and hellgrammites will eat anything in a cell with them; two, this facilitates counting the organisms according to taxonomic and water quality groupings. Some of the creatures are surprisingly mobile and may crawl out of their cell or even the tray. All students will be encouraged to identify a particular animal using their judgement as well as their teammates’. For most of the larger macroinvertebrates identification is really pretty easy.

7. Students should tally identified invertebrates, recording how many of each type they find. This is a job for a group recorder. This may take an hour or more of sorting for each pan. Frequent breaks may be needed.

8. A Large chart, listing each macroinvertebrate in a format similar to that found on the survey form will be used to compile all findings for each site. Each group can enter the number of each macroinvertebrate type they found (i.e. 10 stoneflies, 5 gilled snails, 20 dragonflies, etc.). The total for all groups is recorded on the chart, database and on a master survey form. The results for each site should be kept separately. Students should be asked to complete one survey form based on their own samples. A second survey sheet can be completed by each student showing overall water body results. By using separate group survey forms, it should be possible to show results for each habitat type sampled. All project results can be kept in a database prepared by the students for that purpose.

Evaluation of Water Quality:

Instructors will explain the use of the Record Sheet. (See analysis below.) Raw numbers and distribution among water quality groups will be used to informally estimate water body quality. Students can discuss possible impacts to water quality in general and the sampled water body in particular.

The number of macroinvertebrates found in each water quality group is determined and then multiplied by the appropriate group factor (i.e. # of organisms x 3 = index value for sensitive indicators, # of organisms x 2 = index value for somewhat tolerant indicators, and # of organisms x 1 = index value for tolerant indicators). These values are added together to get a total index value. Values > 22 indicate excellent water, values of 17-22 are good, 11-16 is fair and < 11 indicates poor water quality.

Remember that the important point is not to have all good water species and no bad water species. Instead, a high quality water body will have a wide diversity of all indicator types from sensitive to tolerant, with, hopefully, a larger number of sensitive or moderately tolerant organisms. Also, this system was originally designed for clear, flowing northern U.S. streams. Although scores and techniques have been modified slightly, it does not always accurately assess all waters. A relatively clear, fast moving stream might give you different results than if you sampled a farm pond. Both water bodies may have perfectly operating environments with no pollution impacts; however, the stream will have many sensitive indicators such as mayflies and probably rank as having excellent quality, while the pond will probably have more moderately tolerant organisms such as dragon flies and give a rank of good or fair. This is primarily due to oxygen levels, water temperature and habitat availability.

Sampling which finds little variety in the type of macroinvertebrates found, but high populations of each may indicate water enriched with organic matter. Locating only one or two types of macroinvertebrates in very high abundance indicates severe organic enrichment. If a good variety of organisms was found but at low numbers then toxic pollution may be indicated; however, other problems could also cause reduced populations. This program works best when the same or very similar water bodies can be sampled over time so that results can be compared. However, since use of the sampling program for demonstration purposes generally precludes that possibility, it is up to the instructor to gain as much familiarity as possible with what can be expected of different water bodies. This will allow reasonable comparisons and interpretation of what is found in the demonstration water body.

1. The students will be observed and evaluated based on the following:
2. Cooperation with team members and teachers
3. Quality of Work
4. Time management
5. Accuracy when identifying and classifying macroinvertebrates
6. Lab and field techniques
7. Research techniques
8. Use of Technology Equipment

1. Aspects of water pollution can be discussed in association with what pollution does to the life of a water body.
2. Discussions on food webs can begin with vegetation and algae growing in water and continue all the way to fish and humans. The macroinvertebrates found during the program form a lower or middle area of the food web, between vegetation and minnows or larger fish. Within the macroinvertebrates there are good examples of smaller food webs because some of the organisms are grazers or detritivores on the fungus and plants (mayflies and stoneflies); some are filter feeders (caddisflies); and some are carnivores (dragon flies and damselflies). If a relatively good microscope is available, placing a drop of water on the slide and allowing students to look at it on their own will show an entire new layer of the food web in the diatoms, flagellates and other microorganisms present.
3. The concept of watersheds is an important aspect of water pollution control, which can be discussed either before or after the sampling program. A watershed is the land area, which acts as a collection basin for rainwater, which eventually flows, to a single stream or river.
4. Nonpoint source pollution is another aspect of water pollution, which can frequently be identified by macroinvertebrate sampling techniques. Stream sampling, along with field scouting of the watershed can frequently locate water quality problems not readily identified by conventional water quality sampling.
5. Mapping each site using the longitude and latitude information gathered with the Satellite Navigator.
6. Make seasonal comparisons of sites by using digital photos and field notes.
7. Conduct chemical testing of water samples i.e. Dissolved oxygen, nitrates & ammonia levels etc. Compare these findings with those made counting the macroinvertebrates.