in article , Limnophile at
wrote on 5/25/04 8:14 AM:

I'm going to try the ecosphere idea again, and I'd like some suggestions, or
corrections if anything written here is a bad idea.

I plan to use an old gallon jar ( 3.8 liters) with a tight-fitting lid, a
cup of pond mud, a cup of used aquarium gravel, about a dozen leaves of
duckweed ( Lemna minor) , a small Hygrophila plant, a small Anacharis plant
, some small bits of algae, some copepods, 3 small snails, and 3 ghost
shrimp. I plan to leave about 1/2 a liter of air in the top when I seal the
jar. The room temperature is a constant 72 to 77 F , and the jar will be
placed next to a west-facing window.

Any species I should add or leave out ?
Anything here sound like a problem ?
Any other ideas ?

Limnophile


I worry a bit about the duckweed. In ponds it usually signals a not very
healthy pond ecology. It cuts off light to plants beneath it, I tend to
think it cuts down on the surface area of the water, limiting the exchange
between water and air. Of course the hope is that the plants will free
sufficient O2 to take care of the animals' needs, and the light will come
from the side, not down through the duckweed. Still, if it were me, I'd
skip the duckweed.

That and, I used to take customer service calls regarding a commercially
available ecosphere, and what I learned there was that you want a very light
animal population, compared to the plants.

I also worry a tiny bit about the pond mud. If there is stuff in the mud
that is decaying (and there does tend to be), the decay process will use up
O2, too much decay could suffocate the animals. But I really like the "live
cultures" aspect. So I'm torn. Go lightly on the pond mud.

Please let us know how everything goes.

-Chris


--
Chris