On the right we have a clam from the genus
Sphaerium. The European fingernail clam -
Sphaerium corneum is rather common, and I expect this species is endemic also. You can see numerous growth rings, and clearly there was a period when it adapted to differing environmental conditions, possibly when the clam was around five or ten years old. This could have been due to a drought, pollution event, or a hard winter. This picture below is not from the same genus, but shows how you can count the rings to estimate the age your clam. I am guessing it is at least 25 years old!
On the right we have the native snail
Bithynia leachii. These are very common. I once dredged 3 kg of gravel from a very small seasonal stream and there were hundreds of individuals that lived inside the gravel layer.
The middle picture is from the family
Naididae (and now includes the subfamily
Tubificidae - tubifex worms). You can see a segmented body, the redness caused by high levels of haemoglobin, and part of the mud case stuck to the bottom segment of the worm where it secretes the most mucus. They should wave their heads to circulate water in order to achieve oxygen from waterbodies with low oxygen levels; they have both a physiological and behavioural adaptation to live in that environment. There are about a dozen species in the Tubifex genus, including one called
Tubifex tubifex, but they are relatively hard to identify
. If you have a microscope then you might be able to count the bristles (hairs) that provide traction for burrowing into the sediment, in order to identify the worm species that you have, but I am fairly certain it is going to be from that genus. We don't know much about their sexual reproduction, but usually they can divide and grow a new head, so that one worm can become two, so on and so forth. I had some dero worms turn up in my aquarium once using bee pollen and was very excited.
