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Publishing progress!

We do report with proud that one of our favourite printed magazines,  mare (a fine magazine devoted to ocean topics),  finally decided to use one of our tardigrade images. In addition mare journalist Ute Schmidt created a well fitting text in lucid style, which was by no means copied or simply stolen from our internet pages (as some tv people tend to do ...).
This article can be found in mare, issue 67, April/May 2008. By the way, mare always is worth a glance or two - and please believe us, we didn't receive any $$$ for this compliment!

[ inedx of mare# 76 April/May 2008 ]

Index of mare #67. Please understand that we cannot present the text of this article here for copyright reasons.

"Size matters!" - in search for the Locus typicus of Batillipes mirus

Small, smaller, tardigrade - hunting water bears remains a challenging task. As a small helper we are going to present a few images - animated GIFs, which are intended to explain how sand grain screening under the dissection microscope looks like. First of all, even in single layer sand grain coverage there is only a 50% chance to find the tardigrade as it might sit above but as well hide below the sand grains. But still, even below the sand grain it might remain slightly visible like this Batillipes tardigrade:

[ Batillipes under sand grain ]

Batillipes  tardigrade moving under a sand grain of about 1 mm diameter. Only due to the colour of its stomach content it is gaining a little bit of contrast. Otherwise it would be perfectly transparent and invisible.

Furthermore, you should be aware of the fact that Batillipes does note any movement of the petri dish. A moving petri dish is roughly equivalent to a marine water current. As a consequence the tardigrade will stop moving in order to bring all its 48 adhesive disks in safe contact with the sand grain surface. It will wait a little bit until the felt water current ceases and only then re-start with its movements. When moving, the tardigrade is well able to shake huge sand grains. The size relation between the tardigrade and the sand grain as shown below is equivalent to a man moving a rock with a diameter of 10 meters (!).

[ Batillipes moving a sand grain ]

A Batillipes  tardigrade is shaking a 1 mm sand grain. Four images' GIF sequence. The power dwarf can be seen for a fraction of a second, top left (position 12 o'clock).

How can we be sure at this low resolution that the moving spot is actually a tardigrade? The head movements are quite characteristic, just remember that Batillipes is blind and that it has to sense the limits of its environment by means of its head movements:

[ Batillipes on sand grain ]

A Batillipes  tardigrade. The head is directed downwards in the image. Characteristic head movement. The hind legs are difficult to see in this sequence but clearly present (though not moving).

When trying to reach higher magnifications under the dissecting microscope we quickly reach the resolution limit. The scale bar in the image below indicates that the tardigrade shown has a modest body length of about 175 µm. So we feel slightly envious when reading in the literature that the species Batillipes mirus might reach "up to 720 µm" in body length.

[ Batillipes on sand grain ]

An adult Batillipes sp.  tardigrade with about 175 µm body length.
The big comparison scale line indicates the size of an adult Batillipes mirus (700 µm body length) as quoted in literature.

Of course we would like to investigate the anatomy of those maritime tardigrades more closely. It is quite clear that we would prefer giant individuals for this task. As a consequence our plan was to travel to the "Kieler Föhrde"in Germany from where those giant Batillipes mirus individuals are reported in literature.

In the next issue we will tell you about our expedition to this legendary place, quite close to the city of Kiel in Northern Germany. Of course, we are working scientifically, with a global positioning system and we make use of a special bus in order to come close to this Föhrde spot (well, to be honest, it is a public bus line run by the city of Kiel, coming close to our target area ...). See you.

© 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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