In high school I was given a project to build a completely closed ecosystem that would survive with only light from outside its glass walls. My partner and I built one that seemed to work quite well. We had an aquarium with two small fish (I think tetras), two plants to provide oxygen, blood worms living in the rocks to eat the fish waste and keep the ammonia in check as well as to be the food for the fish. After a few weeks we noticed a small, black rock snail cleaning the algae off the sides of the tank for us. It was beautiful.
But I can’t seem to reproduce it. I just tried putting the same thing together and the worms have died in less than a week. In school, our system lasted five months and was looking as healthy as when we started when the end of the school year came around. Mine now is cloudy, and with the loss of the worms, I’m not too hopeful about the one red-eye tetra I have in there. Does anyone know how to make a completely sealed ecosystem that works? If so, what creatures do you use? Does it have to be a certain temperature?
Anything else that seems relevant would be great to hear. Thanks.
-Kymri
Well yes there is a company that builds ECO-SPHERE which is a glass sphere that contains Brine shrimp and usually a brown, or blue green algae. The bottom is rock. My son has one that he has had for over a year now. But get ready it costs close to 300$USD for the 9 inch sphere. Also you must keep it in indirect sunlight, for the algae and the basic evaporation and condensation to occur.
Also, check out the BIO-SPHERE which is located in oracle Arizona, great place been there a couple of times. This is a monsterous self-sustaining place. it is all glass and it has 4 separate eco systems in it. It looks like a huge green house.
As for being able to build a self sustaining eco-system yourself. I would think you could do it with brine, salt water, a stick that will slowly decompose and some algae. The system would have to be completely airtight…
Have you got a spare planet? I’ve always wanted to try it on that scale…
You can build these closed ecosystems (often called “bottle biology”) pretty easily. Most of them will last for weeks or months, but some will last for years without adding much to the system besides sunlight.
What you probably want to start with is some spring/pond/creek water (highly preferable over tap water), an aquatic plant or plants (Elodea is easy to get in most pet shops. You might also want to try Duckweed.), some rocks (if you can, get rocks that have been in someone’s fish tank or pond for a long time so they will seed your ecosystem with bacteria. Sterile rocks can also work, but if you can get your bacterial community rolling it’ll help. If you don’t want to try Tetras again, you might want to use guppies for fish… but I’m quite leery of putting fish into these kinds of small, enclosed systems. It doesn’t strike me as all that good an idea, and I’m sure it’s not great for the fish either.
One of the nice things about the Elodea (and other aquatic plants) is that it will often contain snails’ eggs, and other little critters that will seed your tank nicely. If you can collect these directly from a freshwater site, you may want to do that too.
Well, I’d recommend against trying to build an enclosed saltwater system. It can certainly be done, but it’s more difficult than building a freshwater system on your own.
Building such a thing is possible, but very tricky. The bigger it is, the easier it will be. If you only have a tiney cube, then you must balance everything exactly and hope nothing changes. Basically if you can keep that small an ecosystem going, you’ve got a lot of luck on your side. While many will last months, there will usually be some limiting factor to it’s healthy lifespan. I’d recommend grabbing a gallon jar full of pond water, with whatever creepy crawlies are in that. Fish may be more difficult to sustain since they eat a lot; invertebrates and bacteria combined with plants work the best - and those from ponds are likely to be used to extreme conditions and temperature fluctuations likely to occur in a tiney closed container.
