This miniature ecosystem has been thriving in an almost
completely isolated state for more than forty years. It has been
watered just once in that time. The original single spiderwort
plant has grown and multiplied, putting out seedlings. As it has
access to light, it continues to photosynthesize. The water
builds up on the inside of the bottle and then rains back down
on the plants in a miniature version of the water cycle. As
leaves die, they fall off and rot at the bottom producing the
carbon dioxide and nutrients required for more plants to grow.