I recently made a biosphere in a bottle for a science project. This is a bite sized ecosystem in a jar. Here is my recipe and a video on the biosphere I made:
Disclaimer: This recipe is based on my biosphere but I cannot guarantee that it will succeed.
Making a self-contained biosphere
½ CM Gravel which can be found at the school baseball field or anywhere else with gravel.
½ CM Activated charcoal which can be bought from pet stores.
2.5 CM Soil which can be found anywhere with plants.
Abiotic elements: A moderately large and nice looking rock that will be the centerpiece of the biosphere. You can find this almost anywhere outside.
Biotic Elements: Grass, leaves, A 3 leaf clover, worms, Small bugs I think are ants, that I put in by accident and I can no longer see.
How to build:
1: Put about ½CM of gravel into the jar, find coffee filter/activated charcoal.
2: Insert filter ½ CM, be sure it covers the full layer.
3: Insert about 2.5 CM of soil. (Note: This is the part where the bugs likely got in.
4: Scatter around abiotic and biotic elements making sure it looks nice and orderly. Make sure plant roots are buried in the soil. Designer Tip: The bugs and worms seem to burrow through the soil which improves the aesthetics.
5: Insert about 100ML of water which may or may not drown the worms.
6: Close the lid but not fully or else the biotic elements will suffocate.