A view of the city of Munich - slightly different (III)

Dear readers, as microscopy enthusiasts and highly complex multi-million cell systems you are already perfectly aware of the existence of the microscopic life all around you. No need to tell you.

But not everybody on this world is so lucky as to be informed about those parallel worlds by teachers and parents. Nevertheless there are moments when those different worlds are meeting and intersecting. For example, when a child (still being able to do some visual close-focusing) is perceiving those tiny red dots moving around on sunny pavements and cement walls. In those moments it becomes common sense for everybody that there might be tiny worlds inhabited by beings quite different from "worms".

We do still remember those moments of enlightenment in our own childhood, many years ago. Today we know that those tiny red moving spots are in fact mites. They show an enormous color contrast with respect to the urban pavement.

And they are quite impressive when seen under a microscope:

Red mite from Munich city pavement moss. Body length ca. 0.5 mm. Apparently it has no problem with temporarily flooded pavement areas. And no, it doesn't feed on tardies. As the mites are active in the dry moss and the tardigrades are resting in the dry moss (forming so-called tuns) the mites and the tardigrades are actually present in the same areas but nevertheless live in different circles.

But there are other distinctive signs of life in the microscopic pavement world. Particularily attractive are those green cell systems as shown below. Being hydrophobic in character they can float on wet pavement and can spread all over town. We are not perfectly sure but we think that those green elements might be early development stages of pavement mosses:

Baby moss? Diameter ca. 0.5 mm. Incident light.

Baby moss? Detail view, transmitted light. Green chloroplasts are visible within the cells.

But the tardigrades, and they were not few, remained slightly mysterious to us. We found only one species of Macrobiotus individuals. Many adults and seniles but no youngsters and no eggs at all.

Typical tardigrade as found in Munich city pavement moss. Body length ca. 300 µm.

Similar tardigrade but with a completely different stomach-intestine content. Obviously there is enough food around and the individual tastes might be different. Image width ca. 200 µm.

Senile Macrobiotus sp. tardigrade. Detail view of the backside with numerous brown pigment stains.

With respect to the missing species determination eggs would have been of particular interest. Macrobiotus hufelandi eggs are showing characteristic protrusions - we didn't find any of them. But we found many males which looked quite active.

Detail view: testis of the Macrobiotus sp. male shown above. Image width ca. 0.1 mm.

Well, we will have to look out further for some hidden eggs later on. It is not Easter time yet.

© Text, images and video clips by  Martin Mach  (webmaster@baertierchen.de).
Water Bear web base is a licensed and revised version of the German language monthly magazine  Bärtierchen-Journal . Style and grammar amendments by native speakers are warmly welcomed.

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