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Re: Aquatic Plants Digest V3 #144

Olga wrote:
> [Re: closed ecosystem]
> Am I wrong in thinking that this would be impossible. Surely the sphere
> could not be completely enclosed. The living things would need air. 

Certainly not impossible.  I have something called a BioSphere, which
is a 10" glass sphere that is completely sealed.  Inside is hornwort,
some tiny floating plant (the brochure called it "chain of stars"),
algae, snails (pond and ramshorn), daphnia, and other tiny
invertebrates.  Originally there were a couple of shrimplike amphipods,
but they seem to have died out.  I can't be sure though.  In any case,
the hornwort produces enough oxygen for the animals, and it all seems
reasonably stable, at least in the three months I've had it.  All it
needs is a good light source.

Berkeley, CA