Understanding:
• Ecosystems have the potential to be sustainable over long periods of time
Ecosystems describe the interaction between biotic components (i.e. communities) and abiotic components (i.e. habitat)
- They are largely self-contained and have the capacity to be self-sustaining over long periods of time
There are three main components required for sustainability in an ecosystem:
- Energy availability – light from the sun provides the initial energy source for almost all communities
- Nutrient availability – saprotrophic decomposers ensure the constant recycling of inorganic nutrients within an environment
- Recycling of wastes – certain bacteria can detoxify harmful waste byproducts (e.g. denitrifying bacteria such as Nitrosomonas)
Skill:
• Setting up sealed mesocosms to try to establish sustainability
Mesocosms are enclosed environments that allow a small part of a natural environment to be observed under controlled conditions
- A terrarium is a small transparent container (e.g. glass or plastic) in which selected plants (or animals) are kept and observed
Making a Self-Sustaining Terrarium
A terrarium can be created using a glass or plastic bottle with a lid, according to the following steps:
- Building a verdant foundation
- Add a bottom layer of pebbles, gravel or sand – this layer exists for drainage (smaller vessels require thinner rock layers)
- Add a second thin layer of activated charcoal – this will prevent mold and help to aerate the soil
- Spread a thin cover of sphagnum moss (or use an organic coffee filter) to create a barrier between the lower layers and soil
- The final layer is the pre-moistened growing medium (i.e. potting mix)
- Selecting the right plants
- Ideally, choose plants that are both slow growing and thrive in a bit of humidity (e.g. most ferns, club moss, etc.)
- Inspect the plant thoroughly for any signs of disease or insects before introducing to the terrarium
- Maintaining appropriate conditions
- Ensure the terrarium is placed in a location that provides a continuous source of light
- Locate the terrarium in a place that does not experience fluctuating temperature conditions (i.e. avoid direct sunlight)
- Do not initially over-water the plants – once the right humidity is established, a terrarium can go months without watering
- Occasional pruning may be required – however, as level of soil nutrients decrease, plant growth should slow down
Example of a Self-Sustaining Terrarium
