Building Your EcoColumn

The EcoColumn starts with the basic units for a TerrAqua Column — an aquatic and terrestrial habitat — and adds an additional unit in between to act as a compost habitat.

What you stock your EcoColumn with involves your goals for study, the sources of your specimens — local or purchased — and your own creativity. To apply concepts from the videos, it will help you to think about including producers, consumers, and decomposers. The simplest way to stock your EcoColumn is to collect from your local environment so that you can model the ecosystem in which you live. To provide a breadth of examples, we combined local collections with purchased specimens to make our system particularly diverse.

Activity Accessories

Depending on the activities you choose to do, you may need one or more of the following:

• Petri plates with prepared media (for “Basically, I’m a Fungi” activity
• 3 Bottle Growing Systems (for “Decomposition Tea” activity)

EcoColumn

Materials Needed

For Building

• Three two-liter plastic bottles (bottle 1 provides a deep base and top, bottles 2 and 3 provide deep funnel units)
• Three bottle caps (for top and deep funnel units)
• One 20-cm length of nylon craft cord (for wick)
• China or non-permanent marker (for making marks)
• Safety razor or utility knife (for starting bottle cuts)
• Scissors (for finishing bottle cuts)
• Soldering iron or drill (for making wick hole in bottle cap)
• Push pin (for making air holes)

Note: For more information on column construction, visit Bottle Basics.

For Stocking and Maintaining

It’s very important that all materials introduced into the EcoColumn — living, dead, or nonliving — are clean and free of anything that might be toxic to living things (e.g., oil, pesticides, etc.). The organisms you introduce should be small and suited to the habitats you construct. The number of organisms you introduce will depend on what they are, but it is better to add too few than too many, especially in the aquatic habitat. Bigger organisms should definitely be limited to one or two.

You can download an inventory of aquatic and terrestrial plants and animals (PDF) that Paul Williams has found make good choices. Many varieties can be collected from local environments and most can be purchased from Carolina Biological Supply Company (1-800–334–5551) or www.carolinabiological.com. The Bottle Biology Web site is also a resource for materials "custom designed" for bottle systems like this.

Aquatic habitat

• Fine grained aquarium gravel (provides “bedrock”)
• Sand or topsoil (provides bottom sediment)
• Untreated tap water or distilled water (provides aquatic habitat)
• “Boulders,” “sunken logs,” and other miniature objects typical of a pond bottom
• Aquatic plants and animals
• Fish food (if you include a fish)

Compost habitat

Fine grained aquarium gravel (provides “bedrock”)

Sand/topsoil mix (provides soil substrate)

Leaf litter (provides compost habitat)

A few chunks of turnips, potato, apple, or other roots, stems, or fruits

Twigs

Earthworms, pill bugs, millipedes, and other natural inhabitants of leaf litter

Terrestrial habitat

• Fine-grained aquarium gravel (provides “bedrock”)
• Topsoil (provides soil substrate)
• Leaf litter (provides decaying material)
• “Boulders,” “dead trees,” and other miniature objects typical of a forest habitat
• Terrestrial plants and animals
• Food for animals as needed

Building Instructions

1. Follow the instructions in Bottle Basics for making a deep base unit, two deep funnel units, and a top unit. An internal unit for either the aquarium or terrarium is optional.
2. Melt or drill a hole in two of the bottle caps and screw onto the deep funnel units.
3. Insert the wick through the hole in the bottle cap of what will be the lower deep funnel (compost habitat) with approximately 10 cm on either side.
4. Invert the upper deep funnel (terrestrial habitat) over the lower and invert both over the deep base (aquatic habitat). Then, secure the top.
5. Add air holes to the upper areas of each habitat.
6. If you wish to string your system, refer to the instructions for stringing bottles in Bottle Basics.

Stocking Instructions

Aquatic habitat

1. Add a layer of sand or topsoil (2-3 cm) to the deep base.
2. Add a layer of gravel (1-2 cm) on top of the sand or topsoil.
3. Add water to a level about 1cm below the cap of the lower deep funnel.
4. Plant aquatic plants with roots in the bottom sediment. A chopstick will help you push the stems or roots into the ground.
5. Arrange “boulders” and other objects on the bottom sediment.
6. Add floating aquatic plants.
7. Let the aquarium sit until the sediment settles.
8. Add aquatic animals.

Compost habitat

1. Add a 1 - 2 cm layer of gravel to the deep funnel.
2. Mix equal parts of sand and topsoil together and add a layer (2 - 3 cm) over the gravel.
3. Add leaf litter and twigs to about 1 cm below the cap of the upper deep funnel.
4. Mix food items in, moving them to the sides of the habitat for better observation.
5. Add compost animals as needed (you will probably collect some with the leaf litter).
6. Establish a “water connection” between aquatic and compost habitats by slowly pouring water down the side of the terrarium until it drips from the bottle cap into the aquarium. This is essential to ensure “wicking” action.

Terrestrial habitat

1. Add a layer (1-2 cm) of gravel to the deep funnel.
2. Mix equal parts of leaf litter and topsoil together, moisten, and add a layer (6-8cm) over the gravel.
3. Add terrestrial animals that burrow to the soil (e.g., worms).
4. Plant terrestrial plants in the soil.
5. Arrange “dead trees” and other objects on soil.
6. Add the remaining terrestrial animals.

Maintenance Instructions

1. Provide a light source, preferably indirect window light. A small desk lamp or plant light will work, too. For artificial lights, provide 12 – 14 hours of light daily.
2. Add a small amount of water to the terrestrial habitat weekly or when it appears to be drying out. A fine spray of water on the plants also maintains the unit well.
3. Remove algae in the aquatic habitat weekly. Gather filamentous algae by “spooling” with a toothbrush or tweezers. Remove algae along the sides of the bottle with a paper towel.
4. Change the water in the aquatic habitat weekly. Use a turkey baster to remove and replace 25% of the water each week.
5. Regularly feed animals that require an external food source.

Petri plates with prepared media

Materials Needed

• One package of 10 petri plates prepared with Sabouraud Dextrose Agar
• One package of 100 sterile swab applicators

Both of the above can be purchased from Carolina Biological Supply Company (1-800–334–5551) or www.carolinabiological.com. Store unused media upside-down in a refrigerator.

Bottle Growing System

The instructions for the Bottle Growing System are provided as part of the Brassica & Butterfly System. There are two suggested modifications for the “Decomposition Tea” activity. The first is to use substrate (i.e., soil) that is free of nutrients. While this isn’t absolutely necessary, if the substrate already contains nutrients, it will be difficult to detect differences due to varying nutrient levels in the water. We used “rock wool,” but other suitable materials include vermiculite, perlite, and dried peat moss mix. All of these, other than rock wool, are available at local garden supply stores. The second suggestion is to use small (740 ml) bottles.

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