Thursday, May 27

Ecosystem in a Jar / Biosphere


As you see on FRONTIERS in Going to Extremes, the middle depths of the ocean are a unique ecosystem, home to some bizarre creatures never before seen. In this activity, you will design and build your own biosphere based on a single ecosystem.


Design and observe a mini-ecosystem.

An ecosystem is a system that has input and output by living and nonliving things knit together as an organized unit. Input can be in the form of energy from the sun or rainwater introduced into the ecological unit. Output is what the ecological unit produces, such as heat, carbon dioxide, oxygen or waste products.

To make your biosphere habitable for life, start with soil, air and water - the media that support the "bios" (life) in the biosphere. You will also need to provide food for the inhabitants inside their enclosed environment.

If you throw a bunch of plants, soil, water and creatures into a glass container and seal it, you'll end up with a pretty wild project. However, it probably will last only a little while. If you want to build a biosphere that will support life, you first need to research and plan. Here's how:


Plan the Biosphere

1. Pick an ecosystem to build or replicate. It can be from your area or from another place on the planet. Try to find a similar experiment or environmental problem in the news to use as a model for your experiment. Maybe you can solve the problem.

2. Determine the needs of the ecosystem. Air, water and soil are important. So is selection of the flora and fauna (plants and animals). You can purchase seeds and plants, then research the needs of insects, fungi and microorganisms.

3. When you determine the species you want, research the type of food and amount needed to sustain life in your biosphere. Figure out which members of the food web should be in the ecosystem to keep everything alive. You may need to provide "imported" food, like worms, for an animal higher on the food chain.

4. Research the size of your biosphere. Size is relevant to food production. If your biosphere has a large consumer, like a mouse, turtle or fish, make sure there are enough plants, animals or both to meet that animal's food needs. For example, a field mouse needs to eat 10 to 100 times its biomass in grass each day.

5. Research the environmental needs of the biosphere. How much water will it need? What is the pH of the soil? What about temperature? Lighting?

6. State a hypothesis about your project.

7. Put the facts together and figure out where to get the species for the project and how to contain them. Your plan should include: the biosphere design, the materials, soil, water and air, as well as the plants and animals that will live inside.

Build the Biosphere

Use a clear container with a "sample" taken from a local ecological unit or your own carefully selected ecological unit. Try grown seedlings or plants, a healthy water supply, soil with microorganisms and other life - everything you think you'll need based on your research and plan. Here are some hints:

• Glass jars (with lids) can be used for small biospheres. Make sure the glass is very clean before you build the biosphere. An aquarium tank is another way to contain your biosphere project. To create a closed aquarium, secure a tight-fitting lid and seal it with tape.

• Collect the species according to your plan.

• Insects can be captured in nets or by hand. Make sure they meet your ecosystem needs.

• Be humane to all living things you use. Do not use endangered or threatened species.

Monitor the Biosphere

Monitor your experiments and write each observation; data collection is important in science. As part of the scientific research you are performing in this project, record as much as you can about the state of the biosphere at the beginning of the experiment. Make a final check at the end of the experiment to compare aspects of your biosphere "before" and "after."

• Take temperature readings at the same time each day or several times a day.

• Check soil and water quality. Inexpensive and simple kits to test nutrient contents can be bought in hardware and gardening stores. Try the pH test. It's fun!

• Population check: count the plants and animals by species. Record the numbers.

• Measure the heights of the plants. Draw illustrations to document physical changes.

Make the Calculations

To measure the results of your experiment, take the data (observations, pictures, temperatures, population records, pH or water quality tests, etc.) and see what has changed or stayed the same in the biosphere. The measurements and recordings you make will help define the change. For example:

1. Calculate growth in plants (from measurements).

2. Calculate declining populations (from counting and recording).

3. Calculate increasing populations (from counting and recording).

4. Calculate percentages of surviving species.

5. Graph and compare changes in temperature, lighting, pH and water quality.

Develop a Conclusion

Based on your data, you will reach a conclusion about your hypothesis. You might:

• Explain results using data, facts and observations.

• Explain the scientific concepts at work in your biosphere.

• Explain similarities and differences between your research and the environmental research scientists are doing locally or worldwide.

• Explain what your team learned from the project.

• Look at reasons your biosphere plan worked or did not work.

• Identify any "cause and effect" relationships to explain changes that occurred during the experiment.

• Present facts on the changes that occurred or process you saw (water cycles, decomposition of materials, etc.).


Biosphere 2, a three-acre, glass-and-steel structure in Oracle, AZ, was created to help us better understand Biosphere 1 -- the Earth. In Biosphere 2, scientists created seven ecosystems, including a rain forest and an ocean. The first experiment in 1991 involved eight scientists (and more than 3,000 species of plants, insects and animals) who lived in the sealed enclosure for two years. They had planned to grow their own food and study the earth's ecology in miniature. However, levels of CO2 became life-threatening, food was insufficient to meet the needs of the inhabitants and the experiment was deemed one of mixed results. 

Today, Biosphere 2 is a research and educational center affiliated with Columbia University; scientists are using the model biosphere to study timely issues like climate change, biodiversity, water resources and rising temperatures in hopes of applying the lessons to the real world. College students from different schools may spend a semester doing research at the facility.

To find out more about Biosphere 2 or to take a virtual tour, go to the Web site and explore the various ecosystems. Or, find out how you can visit Biosphere 2, now open to the public.


• What physical features characterize the middle depths of the ocean? How is this region different from the shallows or ocean floor?

• Describe some of the adaptations different species have evolved to exist in these unusual conditions.

CREDIT: The "Build a Biosphere" activity is adapted by permission from curriculum materials produced by the Biosphere Press.