Everyday tardigrade life in the moss jungle

As already mentioned previously tardigrade photographs taken in perfectly natural environment are rare. Nevertheless there are some situations in tardigrade life that depend greatly on the environment - as a consequence they have to be photographed in this environment as well. Difficult.

Typical sparse moss and lichens growth on the historical cement walls which were intended to tame the 'wild' Isar river on its way across the city of Munich, Germany.

Single moss plant isolated from the scenario
on the left. Overall height: 7 mm.

Mosses are commonly regarded as a dangerous risk for any gardening or cultivation activity in the broadest sense of the word. As a consequence they are tolerated only in a few cultural reservation areas: as a 'bottom carpet' in gift baskets or on the roofs of nativity mangers. There appears to exist some kind of virtual tolerance as well, indicated e.g. by a Windows® screen saver with a densely moss covered cottage.
But most real estate owners do not like any moss growth on their roof tiles or gateways. Those moss cushions tend to be steam blasted or erased even by chemical means: "you see, the pavement becomes soooooooooo slippery with the moss on it, very dangerous for grandma, and the roof tiles quickly crumble away ... ").
Only few of the killing individuals are actually aware of the harmless micro beauties which they are destroying in order to reach some kind of misunderstood 'cleanliness' - not to speak of the collateral tardigrade killing, of course.
Starting with 20fold magnification it becomes clear that the mosses are among the real beauties in kingdom of plants:

Tip of the capsule of a moss plant. The capsule cover (orange) is already slightly opened, below the vault-like grouped red lids of the capsules become visible. Soon the yellow moss spores will find their way out of the capsule container.

The capsules are not only nice to look at. After having fulfilled their primary biological role they are used in a secondary, recycling-type manner by the tardigrades: the water-bears use them as an additional shelter for egg deposition. Instead of despositing their eggs freely outside they crawl to the rear end of the capsule thus caring for an optimum sheltered situation. With some patience we can study this behaviour through the moss capsule wall:

Tardigrade (curved body, green stomach) in a moss capsule during egg deposition, photographed though the wall of the capsule. The two whitish spots (center and center-left) have to be interpreted as eggs.

Why can we feel sure that those faint spots are actually tardigrade eggs? Because we can see the characteristical egg protusions when focusing at their edges with a little bit more (cold!) light:

Tardigrade eggs in moss capsule. The inlay image reveals those typical  Macrobiotus cf. hufelandi  egg protrusions. A well-caring tardigrade mother, isn't she?

© 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.

Main Page