Across the fence: 3D tardigrade simulation

Before ending here you probably did run a quick Google tardigrade "images" search, didn't you? And on this pathway you most certainly found two kinds of tardigrade images: light microscopic images on one hand and scanning electron microscope images (SEM images) on the other.

Those people who have never seen themselves a live tardigrade crawling under the microscope tend to consider the scanning electron microscope images as superior being "more 3D" or possibly "more creepy, more monster like". In addition, some of those SEM images show highly saturated, green moss colour by means of artifical colouring, making the images even more attractive.

Also the tardigrade dry specimens, the so-called "tuns" are sometimes shown on a vividly green moss plant, not taking into consideration that the tuns are formed under strongly desiccating conditions where the moss plant surface area will have turned into a less attractive, brown colour. But we shouldn't blame the colouring artist for this cosmetic improvement as nowadays most female human models will suffer some computer enhancement for improved print product sale as well!

When comparing more soberly between light microscope and SEM images we can state that the light microscopic images are much softer, showing less detail and only little 3D appeal. On the other hand, only the light microscope will show living tardigrades in natural colour and above all, in natural transparency. Just keep in mind that the SEM uses electrons for image formation. And electrons can move only in very thin air, at least partial vacuumm. Even though so-called low-pressure scanning electron microscopes (ESEMs) exist nowadays they will not be able to provide images of living tardigrades. The major reason behind is that the tardigrades are living in water and that the SEM image forming electrons cannot penetrate water. So you will never be able to see a living tardigrade in the SEM through the water. The tardigrade cannot survive for more than a few seconds without the water film around its body. SEM filming of tardigrades is a similar endeavour like filming fishes in air.

Even without the water film electrons cannot penetrate deeply into the tardigrade body - whereas light can. As a consequence the SEM will never be able to reveal the anatomy of living tardigrades nor will it show the eyes (as the tardigrade eyes are hidden beneath a smooth skin layer).



A quite different imaging approach has been performed by Prof. Alfred Vendl and his team from Vienna ("Die Angewandte" = Vienna Technical University). Alfred Vendl did combine the information from static SEM imaging and transferred it into 3D animation. We have received his kind permission to show some of the results.

Here is a link to the trailer (30 sec runtime):

Copyright: www.alfredvendl.com

and a further link to some even more sophisticated footage showing a carnivore tardigrade hunting a Philodina rotifer!

Copyright: www.alfredvendl.com

Technical remarks: Alfred Vendl and his team have been working on the authentic visualization of microfauna scenes for more than 10 years. "Authentic" means that virtually all of the visual properties can be cleanly traced back to actual findings gathered by means of confocal microscopy, micro CT and SEM, all of which are combined to form a very realistic tardigrade 3D model. In a second step of the procedure this static model is going to be animated. The animation procedure is being guided by an expert in biology. The two scenes shown here are preliminary studies for a planned 50 minutes film which will be made in a co-operation among Austrian and Swedish biologists.

Have a nice summer time!

© 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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