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How to Create a Closed Ecosystem Lab

A forest, a pond and a meadow are examples of ecosystems as they are a system of living organisms interacting with each other and the non-living components of their environment. According to the University of Minnesota-Duluth's Natural Resources Research Institute, one way to truly understand how an ecosystem works is to build a model. You can create a closed ecosystem where no nutrients and energy exit or enter the system. As a lab component, monitor the vitality of the system's organisms and modify the physical and biological components accordingly.

Things You'll Need

Large plastic or glass container
1 gallon-sized glass jar and lid
Sand
Soil
3 or more Elodea (or other aquatic plants)
1 pond snail
Ruler
Duct tape
1 sealed plastic baggie
2-3 small fish (guppies or mollies)

Instructions

- 1
  Fill any household container with enough tap water to fill 3/4 of your glass jar; the jar should have a capacity of at least one gallon. Allow the water to sit in the container for at least 48 hours so it can dechlorinate.
- 2
  Pour a 2 inch layer of soil in the bottom of the jar; cover the soil layer with 1/5 inch of sand.
- 3
  Insert three or more Elodea plants securely into the sand and soil layers; space them throughout the jar. Other alternatives for aquatic plants are Zostera, Anacharis and Vallisneria.
- 4
  Place a pond snail on top of the sand.
- 5
  Stand a ruler up in the middle of the jar, so it does not penetrate the soil and sand. Pour the water slowly down the ruler, without piercing the soil and sand, until the jar is three-quarters full.
- 6
  Place the lid on the jar and seal it with duct tape. Place the jar in a site that receives indirect sunlight.
- 7
  Place two or three small fish, such as guppies or mollies, in a sealed plastic baggie with their original aquarium water, a week after the closed ecosystem was created.
- 8
  Unseal the lid and place the baggie of fish inside the jar so the temperature of the fish water will become the same as the system's water.
- 9
  Release the fish into the closed ecosystem after a few hours. Reseal the jar.
- 10
  Observe the closed ecosystem on a daily basis and determine if the aquatic plants, snail or fish are healthy. Experiment with modifying the conditions, such as the amount of light or the number of plants, if it seems like some of the living organisms are frail.

Nature