These sealed glass Beachworld Bio-spheres contain many micro-organisms, algae, plants, snails, worms, and shrimp which are balanced initially in their inputs and outputs, and will maintain a biological equilibrium given only heat and sunlight. The Beachworld Bio Spheres are totally sealed, and need no external air, water, or food. If you're looking for something to motivate you to stick with composting, or to teach your kids about why they have to put their paper in the recycle-bin, instead of the trash, these might be the ticket.