MICROSCOPY- The Swamp III / one year

One year on, and there is an abundance of life in the jar, both macro and microscopic. Vegetation is now mostly on the bo ttom, and it largely consists of algae. More algae at and above the water line, on the walls of the jar. The lights have been on for the most part of the last 6 months, with maybe 48h of darkness in total. Temperature has been a steady and warm 22-24°C.

A superficial visual inspection with the unaided eye shows much activity, with a plaetoria of ostracods happily swimming around looking like they own the Swamp (they totally do). Intelligently estimating their number is an interesting exercise for which I am too lazy right now, but a quick guess would be several hundred of the larger specimens (0.5mm+) and thousands of the smaller ones.

This was filmed with a phone through the wall of the jar and I may have cropped:

Much activity visible with the naked eye – ostracods everywhere

This is a 1.5cm piece of wood at the bottom of the jar. Footage is from above, through the hole for collecting samples:

Ostracods on a 1.5cm piece of wood

The algae colonised the walls of the jar to the point of becoming quite opaque at one point, but then died and peeled off after about 9 months. The walls are now very clean (below the water line).

The most abundant micro-organism is a species of ostracod. This is a fresh water crustacean that lives inside a clam-like structure composed of two valves articulated on the dorsal side that swims around by agitating its antennae and claw-like appendages. Judging by their numbers, the Swamp contains no predators for this creature.

They move about quite rapidly and seem to rely entirely on touch. I saw no interaction between individuals apart from the occasional bump.

They are small enough to become transparent when backlit so internal structure becomes apparent quite easily:

The outside of the shell seems to be covered in what looks like fine hairs:

A different perspective at lower magnification:

And a close-up of its lovely face:

Now this is the interesting bit. I found this pair of paramecia that was twirling around in the same place, not moving about like their friends, and that seemed to be tied together in some way:

Paramecia have largely come to dominate the micro-organisms in the jar, their numbers now far exceeding rotifers, of which I only saw one:

Nematode worms continue to live in the substrate and range from very large ones (cm) to smaller, more agitated specimens. I cannot say whether there is one species of more.

The only rotifer I found. It was not feeding and I only saw it moving about. They used to be the dominant kind of micro-organism for the first 6 months or so.

This is a bug that I see for the first time. It’s large, about the size of the bigger ostracods (1mm) and there seem to be quite a few of them.


As the lightbulb regularly needs replacing I decided to stick it in a wine cork and allow for replacement without unsealing the main cover of the jar.

This came after my first attempt to change the lightbulb without unsealing resulted in catastrophic failure, as can be seen in the photo showing the lightbulb on the bottom of the jar.

The Swamp III is not a closed system, strictly speaking. I am not 100% sure the cork top is perfectly sealed to the glass of the jar and I have completely removed the top three or four times. I also made a hole for collecting samples that I open every time I do so. I have also added several mm3 of starch sometime in early winter. I give it non-stop light and temperature is steady at 22-24°C in winter and 24-30°C in summer.

This being said, it does its own thing in there and provides for excellent observation material. A great little toy.

This is an example of a sample that I collected, with some water, stuff from the side of the walls, from the surface of the water, from the bottom and from the substrate.

The camera records afocally through the microscope

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

MICROSCOPY – The Swamp III / two months

The water is quite clear, as are most of the walls. There is one (barely) surviving plant and some green algae. The snail and the bubble bugs are still alive and happy. Saw a new, large insect cca 1cm.

I drilled a hole in the cork and installed an aluminium tube with an airtight screw-cap. I re-sealed the cork to the side of the jar with hot glue, then covered it with tape. The ecosystem is, for all intents and purposes, sealed, but allows access to take water and other samples.

I use a large-ish syringe on which i put a shrink tube and a plastic cylinder at the end to get the samples through the hole I put in the cork.

Most of the surviving plant life consists of algae. The one plant that seems to be alive has no more green leaves above the water line. The roots growing out of the stem do seem healthy and alive.

The algae are a deep shade of green and grow attached to the stick on the bottom of the jar, on the decaying leaves and on the side of the jar (above the water line).

I switched the light off for one night and there was a new bug floating upside down near the surface. It was still alive but obviously not ok.

There are more and more eggs, with obvious fresh ones appearing on the sides and on the bottom of the jar. Also new batches on the stick as well. The older ones seem to have been colonised by algae and have become green (picture on the left). The “nucleus” of the egg seems to be an elongated, twisted ribbon that looks pretty much like an intestine. It has not changed since the eggs have been laid. I still suspect the snail.

I found the large bug i mentioned before. It died. it’s big, and ugly, and am sure it could crawl out of the jar if it chose to do so. Seal your jars quickly.

Many nematode worms are visibile with the naked eye, about 1-2mm in length, swirling and jerking around the jar.

MICROSCOPY – The Swamp III / one month


There still is life in the jar; very few plants left. Water is surprisingly clear and the algae have all but disappeared from the walls. The twig has sunk well below the water level.

Only one plant seems to have survived. It’s a long thin blade of grass that produced a very nice root that eventually found the bottom. this seems to be surviving and has risen well beyond the surface – it’s flat against the top.

The snail is large 1cm+ and happily wondering around, as are the bubble bugs. Eggs on the stick underwater and on the side of the jar; I suspect the large snail laid them. The algae have all but disappeared from the sides, probably eaten by the snail, as I’ve seen it munch away at them several times. The water is surprisingly clear – I suspect there is not enough light for algae to develop in large numbers. I think the jar *cycled* in the aquarium sense of the term.

MICROSCOPY – The Swamp III / one week

The swamp is most insulting to the nostrils. Became blurry with algae both on the jar walls and within the mass of the water. Large 8-10mm larvae jerking around on the surface. Am expecting mosquitoes which will be killed.


Many, very small organisms quickly moving about. Larger ciliates twirling and swimming about.

A forest of what look like long, green algae but they move on their own, waving around as if in flowing water. I believe they may not be plants.

MICROSCOPY – The Swamp III / day five

Almost a week now, and am happy to report that there are many micro and macro organisms which seem to be well alive and colonising the swamp.

Not many snails, to my surprise. Saw one or two small ones, maybe 2-3mm. And a larger one, some 6-7mm, brownish. The air bubble beetles are fond of the branch (of which 5cm are sticking out) and walk about it underwater in a bubble of air that they somehow pick up from the surface. These creatures are just the right size (and mass and shape) to exploit surface tension.

Saw some flat worms, small, maybe 5mm, many nematodes twirling about. Some daphnia, but not a crowd. Cyclopes, as well. Many larvae, many dead. Saw what looked like a small 2-3mm fly or mosquito hatching from one on a leaf on the surface. All mosquitoes will be killed. I also saw what I believe are carnivorous oligochaete worms. Many ciliates.

The plants seem to be doing well, although there is much muck on their leaves. Saw some roots in the substrate and also fine strands of algae that seem to be colonising it. They are advancing upwards on the wall of the jar.

One very pretty sight are the bunches of Conochilus, that contract suddenly and then slowly open up again. I do believe they grew to about 2mm across, from 1mm yesterday. They seem to be attached to the wall of the jar, and there are many – several dozen.

The bunch of Conochilus


Recorded focally on an APS-C sensor through a 100x microscope

Saw what looked like ticks, several of them. They are on the underside of small, des leaves floating on the surface. Must really seal this jar.

And some spirogyra algae, lovely as usual:

MICROSCOPY – The Swamp III / day two

The water is somewhat clear, with much of the material previously in suspension fallen to the bottom.

Day two – 6.IX.2020


A few (5maybe 6) unidentified beetles cca 5mm long. One seems to have eggs on its belly. They bring bubbles of air underwater and stroll upside down on plants. They climb on top of each other (3 at a time) and relax on the bit of wood protruding from the surface of the water. Some lay motionless among the plants on the bottom.

A snail, possibly more:

Any what I believe to be mosquito larvae. This mens I have to seal the container and find a way to gas them.

The beetles carrying water bubbles underwater:

I saw nematodes, a considerably larger snail-looking creature, green snails, what looked like paramecia and the crustacean-looking things.



September 5th, 2020. Day one.

This is a closed ecosystem that has little to no exchanges with the outside environment. Collected September 5th, 2020 from a 20 year old fishing pond (ex-quarry).

The Swamp III -sealed jar with pond water, plants, decaying organic matter and a pebble substrate

Contains: cca 2,5l pond water. pebbles, water plants and cca 0.5l muck scraped off the bottom.

River pebbles and water plants

A selection of the water plants collected from the pond:

Water plants from the pond

LED lights shining at 370 lumen.

The light setup

Week 9

The jar has been placed outside now for 3 weeks. Weather is uncommonly warm and no rain. Water level dropped several times and was re-filled with bottles still water, tap water (pretty stupid, because it’s full of chlorine) and sparkling water. It never fell below 50% of the volume.

Photo jar week 9

A water sample was collected today from a freshwater flowing lake (particularly clean these days), together with a small clam, algae and muck scraped-off a semi-submerged rock.

Sample contains oligochaeta, nematodes