O'Neil cylinders

Ed Minchau wrote:

> -. We must have
> learned quite a lot from BiosphereII, for instance which plants and
> animals are best-suited to maintaining a complete food cycle in the
> isolated environment.
>

Actually, the lesson I took away from biosphere II was that you can pack
almost any largeish collection of animals and plants into a closed chamber
and you'll probably be okay. Consider this: the very first time they closed
the system and ran it for a year or so it more or less worked. There were
lots of problems, but the system didn't simply crash entirely -- which is
what I expected at the time. This kind of success is very unusual for any
truly new engineered system. Obviously, some species will die out and others
will expand. However, if you don't include anything you don't like and make
sure you can survive the elimination of any small set of species, my
hypothesis is that you should do okay. I think the biosphere II results
support this hypothesis, although obviously they don't prove it and much more
testing is necessary.

A small test of my own: my daughter put some soil and a flower plant in a
plastic container and closed the lid tightly. She gave it to me and I put it
in back of the house and ignored it for months. It's still alive. The
original flower died, but grasses came up and they seem to be reasonably
happy. I'm sure it's not completely gas tight, but it's tight enough to keep
the water vapor inside.