MICROSCOPY – The Swamp III / six months

The Swamp III sample has been collected at the end of summer, in early September. Now, after having spent the winter months inside at a comfy 22-24°C (rather warm, really) I am happy to report there is still life inside the jar: both plants – well, algae to be more precise – and protozoa. Anything moving at this point is alive because it reproduced.

The LED lights that were initially installed eventually died, and were replaced after four months or so. The cap was re-sealed on this occasion (hot glue in between the cork and the sides of the jar, with electric tape on top). I kept the lights on for months at a time to make sure the algae were producing sufficient oxygen and food for the protozoa. After the lights went dim and then died I added a pinch of stark to compensate the loss of light and feed the creatures inside. For the last couple of months I switched the light pattern to the normal day / night alternance and significantly reduced its intensity (placed under a lamp rather than the LEDs inside).


The walls of the jar have became almost opaque with the algae growing on them. Some are long filaments that seem to be growing on the walls, in the body of water and above the water line. There is also a much smaller variety, that sticks to the walls and makes a fine, green film. The substrate is black mud and pebbles; it seems to be partially colonised by a lighter coloured algae-type organism. Will have to check in more detail.

There is no sight of the snail or the bubble bugs. There is no movement that can be seen with the unaided eye. Using a 25mm eyepiece for astrophotography as a loupe allowed me to see the larger protozoa swimming around the jar, so they managed to survive and reproduce. It would be interesting to know how many generations have spawned since I collected the sample.


I collected samples from the body of water, from the side of the walls and from the substrate. First inspection shows algae and protozoa – the jar is alive and I can now reasonably say that I have a self-sustaining ecosystem.

Rotifers are alive and well, they seem to feed happily and there are many of them. I could see different sizes, but there seems to be only one species (Bdelloids). They have really multiplied and are present in great numbers in any sample I take from the jar. It seems they reproduce asexually and all are females.

Rotifers after six months in the jar

More elusive but equally abundant paramecium. They are particularly active and move very fast through, and out of the field of view. here’s a calmer one:

Not many, but rather large nematode worms. I didn’t see them in all samples I collected from the jar but the ones I did manage to catch were huge (several cm) compared to the ones I saw in the beginning (max 1cm).

Large nematode worm

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