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Estuaries are nursery grounds for many species including fish, oysters, crabs, and shrimp, and they are some of the most productive ecosystems in the world. Approximately 92 to 98% of the Gulf of Mexico's commercial fish and shellfish rely on the estuarine area for habitat, protection, and food. Today, our estuaries are being destroyed because of natural processes such as erosion and man-made or anthropogenic causes such as dredging of channels and point and non-point source pollution. The hope for these estuaries rests in educating and fostering stewardship in students regarding the value of these natural treasures.
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Students will be able to do the following:
- Create an estuarine ecosystem in an aquarium.
- Record daily observations in an aquarium log book.
- Discuss the interaction of organisms in the ecosystem.
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(Per group)
- Aquarium (20-gallon)
- Sand
- Gravel, rocks, and larger stones
- Aquarium filter
- Pump
- Aquarium light and lid
- Scine
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- Water
- Salt packet
- Two buckets for collection
- Dip net
- Student constructed turbidity chart
- Refractometer
- pH meter or litmus paper
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Activity
- The cooperative learning groups will begin constructing their own estuarine ecosystem in aquariums.
- The students will place sand and gravel on the bottom of the aquariums.
- After these materials are in place, the students will add water to fill the aquarium to 1 ½ inches from the top. (Note: this water should have a salinity equal to an estuarine habitat. This salinity can be created by adding pre-packaged salts, purchased at the pet store, to tap water that has been allowed to stand in plastic buckets for at least two days to eliminate the chlorine. Chlorine levels may be depleted more rapidly and completely by aerating the water in the buckets).
- Allow the aquarium to stabilize for two weeks before adding any plants or animals.
- The class will take a field trip to an environmental research station to collect live species of plants and animals for their ecosystems. The teachers should stress that students are trying to duplicate in their classroom what they had observed in nature.
- Review proper collection procedures with the students and note that even though they are collecting specimens, they should take care to do as little harm to the environment as possible.
- Collect plant species from the wetland area and the water. Dip nets and seines should be used as methods to capture fish and various organisms. Driftwood, shells, rocks, and other items can also be collected and placed in the aquariums. Be sure the bucket that contains plants has enough water to keep them moist. The animals collected should be placed in buckets containing water from the environmental research station. If possible, field aerators should be used to increase the survival rate. Caution students to maintain collected water as free of sediment as possible.
- Upon returning to class, students should gently place organisms in their respective aquariums and make their initial data entries in their aquarium logs.
- Students should record daily observations in their aquarium logs to include the following:
- Description of plants (growth and loss)
- Number and condition of animals
- Turbidity (using student-constructed turbidity measurement chart)
- Dissolved oxygen measurements
- pH measurements
- Interactions between plants and animals
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- Graph the data from the aquarium log.
- Write a story about your estuarine ecosystem.
- Choose one organism in your aquarium and discuss its role in the ecosystem and how it interacts with other organisms.
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- Observe each group's aquarium, noting individual student participation and procedures.
- Grade the student's aquarium log for adherence to directions and
completeness.
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Marine & Aquatic Habitats Activities - Understanding Estuaries