Mini Ecosystem in a Bottle
If we put soil and plants into a closed room, we create circumstances to get a deeper understanding of basic life processes and interplay in nature. Facts we earlier learned about respiration and photosynthesis in plants suddenly become much more challenging when we put them into a sealed room! – Will they manage to survive, and if they do, how can that be possible?
The life processes that evolve within the bottle can feed discussions from kindergarten to college or university level. In the earlier ages the pupils may just wonder about the beauty and magic of “the enclosed garden”. Higher up, they may have discussions about the different types of circulation that keeps the system alive, or of self organisation and system dynamics. The bottle provides us with a simplified overview of how an ecosystem or the entire biosphere works. It is also a useful model when we discuss carbon dioxide sinks, greenhouse effect and climate change.
Group or Individual / Experiential
Understanding of the basic components of biological life
Experiential understanding for how ecosystems behave in a closed system
Required Materials and Tools:
A glass bottle that can be closed (1 to 25 litre)
Plants (with small leaves, for instance Ficus pumila, Hedera helix, Sedum spp.)
Funnel with a wide opening or a rolled newspaper
Rods or sticks long enough to reach the bottom of the bottle
Make sure that the bottle is clean.
Put a sufficient amount of soil into the bottle by using the funnel and the stick. Be careful so that you don’t get a lot of soil on the sides of the bottle. It is often good to use fresh planting soil, with a high organic content, directly from a flower store. (But of course if you put a cactus inside if you choose soil that suites that type of a plant).
Take the stick and make a small hole in the soil where you wish to plant the plant.
If the plant is too big to enter the bottle, carefully divide it and compress the soil around its roots.
Hold the plant in the upper leaves and put the compressed roots inside the bottle. Aim at the prepared hole and drop the plant. Use the sticks to make sure that the roots have sufficient contact with the surrounding soil. Repeat if you want more plants inside.
When satisfied close the bottle and put it in a place with good light conditions, but not in direct sunshine!
Usually you don’t have to add any water, but if you don’t see condensed water inside the bottle at any point after closing, it might be necessary to add a small amount.
Maintaining the system - light and water
Since the bottle is closed it is very easy to take care of. The most important factor is of course that the system receives enough light, but without the risk of becoming overheated. That means that you might have to protect it from too much radiation during the summer and add additional light during the dark part of the year. Experience is that systems most likely collapse during the dark season.
Another factor that that sometimes creates difficulties is that you add too much water. We are so used to taking care of our pot plants by watering them once or twice a week that we tend to give the plants in our bottle too much water from the very beginning. Usually the moisture in the soil is enough, also because that metabolic water is emitted as the bacteria begin to decompose the organic material in the soil.
Do you think it will survive?
For how long can it grow?
What happens when the “life space” inside is filled up?
What keeps the system in balance?
How does the circulation of water and minerals function?
Will the bottle gain weight as the plants grow?
Who or what regulates the amount of oxygen and carbon dioxide within the bottle?
Instructions for Submission
Upload 1 photo of your bottle and submit your written reflection in Moodle (so that your peers can give you feedback). The written reflection is based on the questions under the “reflection section”. Instructions on how to upload photos and how to submit things in Moodle can be found here: Instructions on Submission&Uploading
Instructions for Assessment
Provide feedback to at least one participant that has done this activity. Instructions on providing feedback can be found here: Instructions on Feedback
Creative Commons - ySI4R Content Team (Inspired by the work of Wolfgang Brunner)
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