Maintaining very small ecosystems

For Christmas, I purchased an "Ecosphere" (c.f.,
http://www.eco-sphere.com/) for my wife's stepmother. They can be found
at Nature Company or Discovery Channel stores in shopping malls.

Ron Menich

"D Evans"
ssi_list@...
05/30/01 03:23
PM
Please respond
to ssi_list

Hi All

Clair Folsome did some pioneering work on small closed ecosystems out in
Hawaii in the 70's-80's. He basically went down to the sea with bottles and
scooped up various bits of algae and microbial life. He then closed the
bottles and set them in a reasonably warm and sunny place and let them get
on with it. Small functional ecosystems soon arose out in many bottles.

I'm pretty sure I read somewhere that many of these systems are still
closed
and still functional. I gather that its not hard to get a stable closed
ecosystem if you are prepared to take whatever random result survives.

This state of affairs, of course, does not bode well for human habitable
closed systems and I think this is Tonys point. An orbital ecosystem that
continuously spiraled itself down into grass, rabbits and people would not
be attractive. I expect that getting a stable ecosystem in orbit would be
fairly easy - getting one you want will likely be very hard.

Some interesting links are below

Summary of papers:
http://www.biospherics.org/cfolsome.html

Kevin Kellys Book (Out of Control) Chapters
http://www.well.com/user/kk/OutOfControl/ch6-e.html
http://www.well.com/user/kk/OutOfControl/ch8-d.html

Your own mini closed ecosystem
http://www.eco-sphere.com/care_manual.html

In particular the Kevin Kelly book is well worth a read - the entire text
is
online.

Regards
D Evans

>
> I have been toying with an idea now, for several weeks. I have a friend
at
> the University of Surrey, who recently graduated and wrote his thesis in
> plant biology. Together, we have been examining the problems associated
> with small-enclosed ecosystems, primarily the build-up of organic toxins
> and the instability of the atmosphere. The biosphere-2 experiments found
> that the balance of gases within a small ecosystem is unstable. Oxygen
> levels can fall to intolerably low levels. In the case of the Russian
> BIOS-3 experiment, the plants produced too much oxygen. The atmosphere
was
> effectively emptied of CO2 and many plants could not photosynthesise. The
> atmospheric balance of biosphere's tends to swing between the two
extremes.
> The human inhabitants of small biosphere's could compensate for
> varying atmospheric gas concentrations, if given enough time. If the
> atmosphere were found to be depleted in oxygen, more flora could be
> grown. If the atmosphere were found to be too rich, a portion of the
> flora would be removed.
> What is needed most of all, is a mechanism that buffers the effect of
> ecosystem changes and allows the crew time, in order to react to the
> changing needs of the habitat. A mechanical atmospheric processing
plant
> is required. If high levels of CO2 are registered within the
atmosphere,
> the efficiency of photosynthetic organisms that convert it into O2 and
> sugar will increase. The huge CO2 swings within a biosphere can easily
> swamp this ability. A mechanical atmospheric processing device,
equipped
> with both a CO2 and O2 gas storage tanks, could be used to buffer the
> changes. If too much CO2 is produced, the system will remove it from
the
> atmosphere and liquefy it. If too much oxygen and not enough CO2 are
> present, Oxygen would be removed and stored and CO2 released. In order
> to compensate for high levels of either gas, rapidly growing algae
could