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Creatures of the Deep: Hidden Depths

Bioluminescent fish, gelatinous sea creatures 120 feet long, archaic cephalopods and other strange creatures are among the new species discovered by the Monterey Bay Aquarium Research Institute (MBARI) in the midwaters of the Pacific Ocean near the California coast. This region of the ocean presents an exciting and challenging realm to explore, containing organisms unlike any others on Earth. Join Frontiers as the crew accompanies the Ventana ROV on a journey down to the middle depths.

Curriculum Links
Related Frontiers Story
Activity: Build a Biosphere
For Further Thought





animals of the sea,


"Model Planet" (Show 601, The Wild West)


As you see on Frontiers in "Creatures of the Deep," the middle depths of the ocean is a unique ecosystem, home to some bizarre creatures never before seen. In this activity, you will design and build your own simple biosphere based on a single ecosystem.


By building a human-controlled, enclosed ecosystem, you will process scientific information, plan and conduct an experiment, observe your experiment and reach conclusions.

Ecosystems in Biosphere 2

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

Biosphere 2 in Arizona was planned as an experiment designed to model life on Earth. Scientists first had to plan and build seven ecosystems, including an ocean, before they could begin their experiments. More than 4,000 species of plants and animals were brought into Biosphere 2, which became a giant lab in the desert.

To build your biosphere, start with soil, air and water -- the media that support "bios" (life) in the biosphere. The medium has to be habitable for life. And you will need to grow food for the inhabitants inside your experiment, just as in Biosphere 2.

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

Planning the Biosphere

  1. Pick an ecosystem to build or replicate. It can be based on the area where you live or on another place on the planet. Perhaps you are aware of an environmental problem in the news that you can use as a model for your experiment. Maybe you can solve the problem.

  2. Research 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 classroom biosphere. Figure out which members of the food web should be in the ecosystem to keep everything alive. You may need to have an "import" for food, like worms, for an animal higher on the food chain to eat. If your biosphere project 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.

    Here is a sample food chain:


  4. Research the size of your biosphere. Size is relevant to food production; even a field mouse could be a challenge. You must have 10 to 100 times the biomass of a mouse in grass for one field mouse to survive.

  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 biosphere project and how to contain them. Your plan should include: the biosphere design, materials, soil, water and air, as well as the plants and animals that will live inside.
Building the Biosphere

Use a clear container with a "sample" taken from a local ecological unit (as scientists did with the Florida Everglades samples for the marsh in Biosphere 2) 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:

  1. 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.

  2. Collect the species according to your plan.

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

  4. Be humane to all living things you use. Do not use endangered or threatened species. Note: some state parks and other areas restrict picking or digging plants, so be sure to obtain permission first.
Monitoring the Biosphere

Monitor your experiments and write each observation; this is data collection, very 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."

Monitoring Ideas

  1. Take temperature readings at the same time each day or several times a day, depending on how long you plan to keep the experiment running.

  2. 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!

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

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


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:

  • Calculate growth in plants (from measurements).

  • Calculate declining populations (from counting and recording).

  • Calculate increasing populations (from counting and recording).

  • Calculate percentages of surviving species.

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

Develop a conclusion based on your data. You might:

  1. Explain results using data, facts and observations.

  2. Explain the scientific concepts at work in your biosphere.

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

  4. Explain what your team learned from the project.

  5. Look at reasons your biosphere plan worked or did not work. What could you have done differently?

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

  7. Present facts on the changes that occurred (water cycles, decomposition of materials, etc.).
More About Biosphere 2

  • You can take a virtual journey through the ecosystems on Biosphere 2 on the World Wide Web at:

  • Biosphere 2 invites middle and high schools to participate in the Global Testbed Project. This multifaceted project incorporates a study of the Biosphere 2 system, computer modeling, use of the World Wide Web, teacher training and more. If interested, look for applications on the Biosphere 2 Web site.

  • This activity is adapted by permission from curriculum materials produced by The Biosphere Press. The Biosphere 2 curriculum package contains over 100 activities and a short video ($29.95). To order or for more information, write to: The Biosphere Press, P.O. Box 689, Oracle, AZ 85623.


  • What physical features are characteristic of the middle depths of the ocean? How is this region different from the ocean surface and floor?

  • Describe some of the ways different species have adapted to an existence in these unusual conditions.


Scientific American Frontiers
Fall 1990 to Spring 2000
Sponsored by GTE Corporation,
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