Now, if you put animals in your mini-Earth, you have to put plants in it, too.
The oxygen that the animals will absorb will be produced by the plants through photosynthesis.
However, as explained below, it is a difficult question to answer properly as to how many animals and plants you should put in.
Basically, you can think of it as "allowing for some leeway".
That means to put in more plants than the animals you have.
Also, you can put in more water than the plants you have.
This is what "allowing for some leeway" shows.
The problem is that it is impossible to tell just by looking at how many animals there are, how many plants there are, and how much water there are for how many plants.
So, I've included some examples of mini-Earth proportions that have worked well in the past.
It is important to note that it is not necessarily the case that "the more plants, the better."
Plants not only produce oxygen through photosynthesis, but also consume oxygen through respiration.
Even if you put in a lot of plants, there is a limit to the amount of oxygen they can produce because they compete for light and carbon dioxide.
However, the amount of oxygen consumed by plants through respiration is roughly proportional to the amount of plants, so if you put in too many plants, there will not be enough oxygen in the container.
This kind of oxygen shortage is particularly likely to occur at night.
So, what is the minimum number of plants needed?
In my experience, you need a certain amount of aquatic plants to keep fish alive, but I think that invisible phytoplankton would be enough for just one shrimp or one shellfish.
So, if you are going to put aquatic plants in the container, what kind of plants should you put in?
You can get a wide variety of aquatic plants at an aquarium shop or by mail order, but the number of plants that can withstand the harsh environment of a bottle is quite limited.
Some of the plants that are easily available are Anacharis (Elodea canadensis), Matsumo, Willow Moss, Screw Vallisneria, and Western Marimo.
These plants are highly resistant to shade and cold, so they are thought to be the best match for a mini-earth.
If you have access to 24-hour air conditioning and can expose the mini-earth to direct sunlight, it would be good to try Rotala, Myriophyllum mattogrossense, and Alternanthera reineckii.
There should be another choice of them.
So, if you find any promising aquatic plants that are not introduced here, please give them a try.
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