This lesson is designed to teach students proper techniques of collecting and identifying macroinvertebrates.Students will learn how to use the data collected to help determine the health of a stream or body of water.
Organisms both cooperate and compete in ecosystems. The interrelationships and interdependencies of these organisms may generate ecosystems that are stable for hundreds or thousands of years. Living organisms have the capacity to produce populations of infinite size, but environments and resources are finite. This fundamental tension has profound effects on the interactions between organisms. Human beings live within the world's ecosystems. Increasingly, humans modify ecosystems as a result of population growth, technology, and consumption. Human destruction of habitats through direct harvesting, pollution, atmospheric changes, and other factors is threatening current global stability, and if not addressed, ecosystems will be irreversibly affected. Natural ecosystems provide an array of basic processes that affect humans. Those processes include maintenance of the quality of the atmosphere, generation of soils, control of the hydrologic cycle, disposal of wastes, and recycling of nutrients. Humans are changing many of these basic processes, and the changes may be detrimental to humans. Materials from human societies affect both physical and chemical cycles of the earth. Many factors influence environmental quality. Factors that students might investigate include population growth, resource use, population distribution, overconsumption, the capacity of technology to solve problems, poverty, the role of economic, political, and religious views, and different ways humans view the earth. Changes in systems can be quantified. Evidence for interactions and subsequent change and the formulation of scientific explanations are often clarified through quantitative distinctions--measurement. Mathematics is essential for accurately measuring change. Literacy Standards Information Literacy Standard 1: The student who is information literate accesses information efficiently and effectively. Standard 2: The student who is information literate evaluates information critically and competently. Standard 3: The student who is information literate uses information accurately and creatively. Technology standards 1.Basic operations and concepts Students demonstrate a sound understanding of the nature andoperation of technology systems. Students are proficient in the use of technology. Technology productivity tools Students use technology tools to enhance learning, increase productivity, and promote creativity. Technology research tools Students use technology to locate, evaluate, and collect information from a variety of sources. Students use technology tools to process data and report results. Students evaluate and select new information resources and technological innovations based on the appropriateness to specific tasks. Different systems of measurement are used for different purposes. Scientists usually use the metric system. An important part of measurement is knowing when to use which system. For example, a meteorologist might use degrees Fahrenheit when reporting the weather to the public, but in writing scientific reports, the meteorologist would use degrees Celsius.
Students prior knowledge should include knowing what macroinvertebrates are and how the types of macroinvertebrates found can determine the health of a stream.
Tools Required A) Collection Nets 1. Kick seine (for swift moving waters) 2. D-frame nets (for sampling riffles and runs, pools, drifting and surface organisms B) Trays, preferably white C) Storage containers for holding and sorting D) Plastic buckets (with lids)for transportation of collected specimens to lab for identification. E) Hand held magnifying lenses to aid in identification of specimens F) Tweezers or forceps for handeling specimens G) Small vegetable brushes for brushing macroinvertebrates from rocks during sampling H) Wading boots I) Thermometer for measuring water temperature J) Meter stick for measuring depth and width of collection site K) Sample record and assesment form
Students will write a research paper that will include their data collected and how the data can be used to determine the the health of the body of water sampled. Students should draw conclusions based on their data and go into detail on what their data suggests and why.
1. Select a sampling site. Sampling should be done in a riffle area with a rubble or gravel bottom. 2. Sample using a kick seine,which requires two people to hold the poles at each end and a third person to shuffle their feet, or d-frame net, hold the opening of the net into the current and one group member shuffle their feet upstream from the net. Benthic macroinvertebrateswill be dislodged by the movement and carried into the net.Take a white plastic and make a grid in the bottom using 5-7 cm squares and number the squares in order. Hold the net over the pan and using water from the stream, rinse the net so that the water and invertebrates go into the pan.Select a starting grid from which to start sampling. Pick al the organisms from one square before moving to the next. Three samples or at least 50 organisms should be collected. 3. Place the organisms in a dish to compare each organism with the previously picked organism 4. Aftercomparing specimens, place each in a petri dish containg similar organisms. This provides a rough sorting of the organisms into major groups to aid in identification. 5. Place the samples in a 70 % alcohol preservative for identification later. 6. Once back in the lab use the Macroinvertebate Identification Key at:http://www.people.Virginia.EDU/~sos-iwla/Stream-Study/Key/ MacroKeyIntro.HTML 7. Fill in data on the Sample Record and Assesment Form
The above url is an online identification key for macroinvertebrates for students to identify the specimens collected and brought back to the lab. River Bank CD-Rom is a database for storing and viewing watershed data;RiverBank compliments GREEN's Field Manual for Water-Quality Monitoring. To get this CD-Rom contact: Green 206 South Fifth Avenue Suite 150 Ann Arbor,MI 48104 (313) 761-8142 email:green@green.org www.econet.apc.org/green/riverbank