Self-Contained Micro Ecosystem in a Fish Tank

If you’re teaching Ecology or Science or just want to observe life cycles in nature, without camping out, consider establishing and maintaining a micro ecosystem in your classroom or home. There are numerous articles and kits for gathering specimens or observing a “slice of nature” in the field. But, few, if any, address the establishment of a portable micro ecosystem.

A recent request by a local teacher prompted me to begin experimenting with a self contained and self-sustaining indoor micro ecosystem, which can be set up and maintained in a classroom environment. Years of working with students and teachers combined with even more years of living and working with plants, insects, animals and observing nature during all seasons of the year have been digested and are a brief outline to help you capture, inoculate and establish a micro eco system.

If you think you’re going to use a ten-gallon aquarium or gallon jar to stock with gold fish, mice, hamsters or similar critters; STOP, reconsider and move on to something else. The self-contained eco system will take several weeks or even a couple of months to settle and adjust to the temperature, light, humidity, nutrients and other environment factors.

This project is designed to set up a small and specific micro eco system – e.g.: Moving water pond, still water pond, or similar complex plant, animal, fungi, and related species of living materials. [Think of a living display like an ant farm, fish tank, or observation beehive without the need to feed or clean the enclosure unless their stabilized environment receives a severe shock of light, temperature, humidity or similar climatic shock.]

To develop a self-contained system where certain select plants, small animals, possibly specialized insects, crustaceans etc. can become established and reach an ecological balance. It won’t happen overnight and may even take several months, a year or more. It’s not like life in a ‘bubble’ because winter dry heat or summer sun will dramatically impact a ‘still pond’ and require water to maintain the water level.

Several preparatory steps need to be considered. Where is the system to be located? Direct sun through a classroom window may provide too much light or heat from the radiator will dehydrate the microenvironment. If the room is windowless or only receives indirect skylight, you will have to add artificial light that provides the necessary lumens and color intensities to maintain microclimate environment. The tank or enclosure surfaces need to be solid enough to protect the life forms inside from the surrounding room or home environment.

A self-contained and self-sustaining micro ecosystem should be closed on all sides. A screen or other suitable opening should permit addition of a new species or variety as well as possible removal of samples for closer examination

Simple lab testing equipment, like thermometer, humidity monitor, PH, nitrate, light intensity and wave length are just a few of the observations possible. Small samples of leaves from plants, snails, algae, fungus and other microscopic inhabitants can be monitored and recorded. These recordings can be compared with samples obtained from the original area where the sample was obtained to seed your microenvironment.

Do not use tap water or distilled water to replenish the water supply, as it will alter the chemistry and mineral content of the system. Depending upon the season of the year, relative humidity of the room environment, you may need to add water and some micronutrients to re-balance the system approximating the native state. If possible, use rainwater and if PH begins to vary, some specialized aquarium and pet shops carry specialized chemicals to reduce or control ‘out of control’ fungi or bacteria. However, remember that most of these will reach equilibrium in your microenvironment if you have carefully selected your sample from the larger eco system.

Your goal should be the establishment and maintenance of a microenvironment that you can observe from the comfort of your home or classroom. It’s a lot easier than trudging through the rain, snow, traffic or other hazards related to moving a class into natural areas of parks or environment preserves.

The real excitement comes in watching the life cycle of the small creatures. Some take only a few days while others change more slowly. Depending upon the plants, you are able to observe the life cycle close-up. If your classroom is equipped with the small computer camera and projection screen, you can focus in, record the movements and life cycle, and present this full screen for all to see. You may also be able to share these with other students and classes using the Internet and share your microenvironments from one part of the country with others around the country or world. Have fun and learn to enjoy and respect the fragile environment live in.