Closed Ecosystem

[LexMortis]

Hello everyone!

I've come here in the hope to get some closed ecosystem advice and hints.
Recently I’ve read the following post on a different site: slashdot

To me that sounds pretty cool and got me thinking; Can I do something similar but cooler/more elaborate? I’ve decided to atleast attempt it.. except I want more than a plant / fungus “loop”. But what to pick / put in?
I’ve had a look around and found this: ecosphere
Doesn’t look too bad, but the loop is rather simple (see here) plus I’ve read the shrimp die after ~3 years (source). So it’s not a fully self-sustainable ecosystem but more of a slowly dying one…

I think the coolest would be some swamp/mangrove ecosystem. I came up with the following. In the water (~10cm?): algae + shrimp/seamonkies + bacteria. Some swamp/mangrove plant half in the water, half sticking out. Fruit flies flying around.
However as I lack bio/eco-knowledge, so I have no idea if that would work, work as in, be stable and self-sustainable. Plus I miss details on which plants/species/etc would be the best for this.

What if an organism goes through explosive reproduction rate, resulting in cannabalism when there is no food left? Will the plant outgrow the jar? Fruitflies too dumb to not drown? Plant(s) growing fast, blocking the sunlight from the algae? etc etc.. plenty of questions/problems/variables. Is it even possible to make any predictions or is the only way to go here Trial & Error? Is it even possible at all?

While this is a cool science project on its own, I am partially going for looks too.. hence I want small critters in it so it's somewhat interesting/cool to look at. So active critters.. plus if there is water it shouldnt get too muddy.

The home for the ecosystem will probably be this glass jar: this.

I think 25L is a good size and the 5” opening should be big enough for me to get everything inside. If someone has a better glass jar or something similar, please let me know (even better if it’s from a Dutch (online) shop).

Any thoughts or advices are very welcome!