Sequence | Background | Objectives | Materials | Activity | Extensions | Evaluations

TOPIC-TITLE Marine & Aquatic Habitats Activities - Estuaries, Estuarine Habitats, and Adaptations AUTHOR Eileen Gray Ann Alexander Tina Darling Nelda Sharkey GRADE SUITABILITY Middle School SCOPE Earth Science Management Biological Oceanography

Sequence As part of a unit on habitats, develop a lecture focusing on estuaries. Show videotapes such as "Finite Ocean" to enhance the lecture and inspire students' enthusiasm. Students will have the opportunity to augment their knowledge regarding estuaries through research, discussion, and by building a model illustrating estuaries and the role they play in our environment. < < go top

Background Summary An estuary is an area where fresh water mixed with salt water acts as a transition zone between these two ecosystems. In contrast to other transitional areas, estuaries have a limited number of permanent residents because of the physical and chemical characteristics of this habitat. Although few different species exist permanently in estuaries, they are among the most productive ecosystems on the planet. For example, in some estuaries, 1 acre of estuary can annually produce 10 tons of plant and animal life. < < go top Objectives Students will be able to do the following: Illustrate an estuary by designing and building models. Explain how the physical characteristics of estuaries can create a stressful environment for organisms. Create a diagram to illustrate an estuarine food web. < < go top Materials Clear loaf pan Blue and yellow food coloring Masking tape Pencil Sand Plastic aquarium Plants (to represent vegetation) < < go top Activity Involve cooperative learning groups of four to five students each in this activity and give each group responsibility for one of the following topics: Estuarine organisms and their adaptations to estuarine life (tolerances to this environment). Ecology of estuaries to include productivity, organic matter, food sources, and an example of a food web. Environmental characteristics--include estuarine circulation, mixing fresh and salt waters (stratification and homogeneous mixing) and upwellings (develop a laboratory exercise to illustrate upwellings). Physical characteristics of estuaries-salinity, wave actions and currents, substrate, turbidity, temperature, and oxygen. Each of the topics listed in #1 will be researched within a group and the results will be incorporated in each group presentation. Each group will work together to design and build a model using the materials listed that illustrates an estuarine environment. Groups will develop and demonstrate a method to show how fresh and marine waters mix. Each group will complete the following: List and define several different types of estuarine ecosystems. Explain how environmental changes can quickly alter an estuary. Explain the importance of estuaries as nursery grounds. < < go top Possible Extension Determine sources of pollution and their effects on the estuarine environment. Investigate the work of Ducks Unlimited, the Sierra Club, or other land or ocean trust organizations in preserving the estuarine systems. Investigate whether your state or local area has any laws designed to protect estuaries. Investigate an estuary either by visiting it or by computer--World Wide Web. Using the following idea, discuss how everyone can be involved in improving environmental conditions: Ocean Heroes--The California Based Surfer Foundation is no ordinary bunch of surfing dudes. They include lawyers and professors who got the EPA to require pulp mills to prove discharges are safe to marine life without using dioxin to produce chlorine. Research how this may have happened. Play "Hydropoly-The Game of Wetlands Management and Economics" (pp. 129-132, Wow! The Wonders of Wetlands) and the Role Playing Game. Develop a model comparing paved surfaces versus marshes. In two pneumatic troughs, put solid, nonporous substrate in first and astroturf to represent spongy material in second. Measure the muddy water (200ml) that is to be put into the system at top of slope and measure the amount of liquid that comes through the substrate, as well as the turbidity of the liquid that has passed through the substrate. < < go top Teacher Evaluation Determine if all teaching objectives were met by the cooperative learning groups. Did all students contribute to group activities? Did students accomplish lesson goals? Based on Student Performance: Observe student groups as they work. Grade model of estuary by determining if all components have been included, such as biotic and abiotic interactions and the food web. Observe students' remarks in the model demonstrations and presentations. Test students on concepts. < < go top