Maintaining very small ecosystems

Interesting recent URL: http://www.spaceref.com/news/viewnews.html?id=355

Ron Menich

Ian Woollard
ssi_list@...
05/29/01 09:31
PM
Please respond
to ssi_list

> 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.

That isn't the case. That particular ecosphere was unstable, but they
messed it up rather (mainly way too much carbon, and not enough light).

In fact closed ecospheres are available over the counter. Fish tanks
are another case in point. There seems to be a Gaia like life stabilisation
principle going on in fish tanks. They're not sealed atmospherically, but
most other chemicals go around and around; except you feed the fish, but
then there are usually too many fish.

You throw everything in, and stir, measure and adjust ratios, repeat,
repeat,
and then suddenly after a week or two it 'pops' and everything becomes
stable you
don't need to adjust anymore; you can leave it.

> 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.

Yes, it can happen. Ecospheres can unravel occasionally. Possibly they
all do eventually. Often you can control it enough to stop everything dying
and then something will happen- some organism will sort out a fix for the
problem and everything will be ok. Too much light in the Russian experiment
perhaps?

> Has anyone on this list conducted experiments with closed
> ecosystems? What is needed is an airtight environment where various
> experiments can be conducted at low cost.

All you need is an airtight jar. I used to do this as a child. Not rocket
science. Working out what the heck is happening IS rocket science of
course.

> Tony
>

civilization?"