An ecosphere is like a mini world inside a clear, sealed container that has everything that a living environment needs to survive. Think of it like a little underwater world that you can keep on a shelf in your house.
Inside the ecosphere, there is water, living plants, and small creatures like shrimp, snails, or other tiny organisms. The water in the ecosphere is specially treated to make sure that it is clean and safe for the creatures to live in. The plants inside gobble up the carbon dioxide that the creatures breathe out and release oxygen into the water, which the creatures breathe.
The tiny creatures also eat and poop, which creates a natural cycle of nutrients and waste products in the water that the plants use to grow, which in turn, supports the creatures living in the ecosphere.
The ecosphere is designed to be self-sustaining, which means that it can keep going on its own without you needing to add anything to it. However, you can still enjoy watching the creatures swim and the plants grow inside this tiny world!