How to Obtain a Closed Ecosystem

In a closed ecosystem, living (biotic) and non-living (abiotic) interactions are limited to allotted space. In nature, only the Earth as a whole is considered a closed system. All natural ecosystems have edges that meet other ecosystems to create a transitional zone that transfers nutrients, moisture and organisms between the ecosystems. Inside a closed ecosystem a balance of moisture, light and nutrients must be achieved before the system can sustain itself. To get a firsthand look at how ecology works, build this closed terrarium ecosystem on a shoestring budget.

Things You'll Need

• Glass or plastic sealable container
• Pebbles
• Sterile sand
• Styrofoam bits or vermiculite
• Cuttings from houseplants
• Spray bottle of water
• Light source

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Instructions

1. Build your closed ecosystem

   • 1

     Line the bottom of the clean container with pebbles.

   • 2

     Mix sand and Styrofoam shards uniformly. Layer over pebbles. Fill container to one-third of its depth.

   • 3

     Use the eraser end of a pencil to define planting holes in the soil medium.

   • 4

     Gently shake excess soil from small plant specimens. Insert root ends into prepared holes. Gently press growing medium around the stems to hold the plants in place.

   • 5

     Spray plants with water.

   • 6

     Replace the container's lid. Do not permanently seal the container until you see moisture condensing on its walls.