Pet stores often sell closed aquatic environments with advertising that states they require no food and no cleaning. They come in sizes as small as a tiny glass jar to as large as one or two gallons. They are self-sustaining because they have all the components required for a living ecosystem in the container.
Understanding the Components of an Ecosystem
All ecosystems, whether they are on land or are water based, require three basic components:
- Producers
- Consumers
- Decomposers
Simply put, the producers are the plants, so named because they produce their own food and are the base of the food web. They also produce oxygen, essential for the consumers.
Consumers are the animals and living organisms that feed off the producers, so named because they consume things in the environment. Consumers also contribute carbon dioxide and waste to the ecosystem.
Decomposers are the garbage cleaners of the ecosystem because they recycle the waste products. Decomposers include bacteria and worms. In a water system, snails and ghost shrimp are decomposers.
Producers, consumers, and decomposers must all remain in balance for the ecosystem to thrive. Too much of one of these will result in disaster. For example, if there are too many fish and not enough plants, the fish will starve or will suffocate from lack of oxygen. Therefore, it is important not to overcrowd the environment.
Choosing the Items for the Environment
To create a one-gallon aquatic system, at least two fast growing aquatic plants are needed. Elodea grows well in filtered sunlight, and is excellent food for small freshwater fish. Fish suitable for this type of biosphere are tetras and other livebearers. One large snail or several small snails will keep the environment clean. Snails multiply quickly, but the fish will eat the snail eggs they find.
Putting the Biosphere Together
- Choose a one-gallon glass jar or clear plastic container that has a tight fitting lid.
- Cover the bottom of the container with aquatic gravel.
- Fill the container with filtered water, and let it sit for at least 24 hours. This waiting period allows chlorine to dissipate from the water.
- Add any decorative aquarium items desired to give it an appealing look.
- Plant the aquarium plants in the gravel.
- Before adding the freshwater fish, snails, or shrimp, allow them to acclimate to the water temperature by floating the plastic bag the pet store provided on the surface of the water for a few hours.
- Once the water temperatures are equalized, the fish, snails, or shrimp may be introduced into the biosphere.
- Close the lid tightly to prevent evaporation.
- Place the ecosystem in a location that has filtered sunlight.
Troubleshooting the Aquatic Ecosystem
- If algae begins to grow in the container, it may need more decomposers.
- If too many decomposers are in the system, the water may become cloudy. Add more plants to provide food and oxygen.
- If fish are dying, add more plants.
This project is perfect for a trouble free aquarium in the home. It also makes an excellent addition to the classroom as a teaching aid for biology concepts in the elementary grades. However it is used, it can be beautiful and functional, a natural self-sustaining system in a custom aquarium.
Suzanne Pitner - Suzanne Pitner is a teacher and published writer. A member of RWA and YARWA, she writes fiction as Suzanne Lilly.
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