Tabula rasa!

Some months ago we had studied a bin shed tardigrade population in the very center of Munich (Germany). And we had been quite impressed by the variety of tardigrades which were living on this cement construction. The moss coverage on the bin shed had not been that intense:

Fig. 1: The bin shed roof under investigation. The red arrow is marking our sampling position in July 2019. We had found a sound mixture of Macrobiotus and Echiniscus individuals and - not surprisingly - also the carnivore Milnesium tardigradum.

A short time after the sampling the cement roof had been thoroughly "cleaned". Nevertheless we had hoped that the roof population might have fully recovered after some time. So we revisited the previous sampling location, tried to get hold of some moss leaflets and immersed them in water as usual:

Fig. 2: Our moss sample taken from the cement roof one year after a radical cleaning procedure. As the moss plants were still very small at this time we could get hold of only a small quantity. So we used a very small petri dish with only 3.5 cm in diameter.

In parallel we were planning to inaugurate our newly acquired "Graf Apsco Steriette" stereo microscope. You know, in German language "Graf" means no less than "Earl" or "Count"!

Fig. 3: "Graf Apsco Steriette 400" stereo microscope built in the 1960s. It has a switch to choose among 15x and 30x magnification. A low voltage bulb can be positioned in tubes above and below the sample thus providing incident and transmitted light. Even though the finish reminds of PanAm and the age of early space technology, only very few of those instruments made their way across the Atlantic Ocean to Germany. Probably one of the reasons for this is the former currency conversion rate between the German DM ("Mark") currrency and the U.S. $ which put US export to Germany into a hopeless competition rank. But there can be no doubt that the Steriette has a unique design and that it can do a good job as a stereo (sample preparation and handling) microscope.

And we found: Nothing! As a consequence we had to go back to our original sample from July 2019. We will show a few tardigrades from this sample here and in the following issues of our magazine. Here is a first example:

Fig. 4: Ramazzottius oberhaeuseri tardigrade, from a moss sample taken before the reported radical cleaning. 0.3 mm body length and well-fed!

It looks like a little tiger, agreed. Nevertheless we should confirm that the small mouth tube diameter is revealing a strictly vegetarian, probably even a mostly vegane character!

© Text, images and video clips by  Martin Mach  (webmaster@baertierchen.de).
The 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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