A tedious and still ongoing expedition from the Sea to the dry land - Echiniscoides sigismundi

Homo sapiens, a humble landlubber and terribly poor swimmer tends to be emotional with respect to the oceans. No matter whether we are thinking about a romantic grotto or about the white shark, the sea has a tendency to arouse our feelings and to stimulate our desire for paradise.

One of the wild borderlines at the frontier between earth and sea: the Atlantic Coast at the very west of Europe (Portugal, Cabo Roca).

On the other side of the borderline, in the Sea, there appears to be some desire for a change as well, but in the opposite direction. Of course there are many problems, e.g. the total reflection prohibiting free sight. Who knows which motives might have driven our biological ancestors to leave the oceans? In any case there is no doubt that the borderline region looks very attractive and tends to whet the appetite for a change.

Lichens on a rock close to the Atlantic Ocean, at Cabo Roca, Portugal.

Difficult to guess how long it might have taken to tranform those desires into active moves. In any case we can be sure that those moves will not have been a matter of days but moreover of many thousands of years. Terrestric tardigrades are considered as animals who have successfully moved to the dry land but still need a small droplet of water - not only a romantic reminicscence of their former ocean-based homes but an existential need.
Some of the sea tardigrades are suspected of secret movement plans and of making a rest in an intermediate area, at the beaches between the oceans and the dry land:

A beach? Yes, but also the favourite recreation area of the tardigrade Echiniscoides sigismundi. The more waves, the better.

Permanent inhabitants of the beach must be extremophiles: the salt content of the beach area is highly variably, it can range between a few percent (as in the ocean) and virtually zero after a rain on dry sand. Algae at the beach can become terribly dry and their dark colour tends to accumulate brute heat energy from the sun. In addition, the waves are sandblasting everything in reach. Under the microscope the algae look quite peaceful, like a fairytale forest, and there is no indication of the highly variable conditions on their surface.

Green algae from the beach, under the microscope. Image width ca. 0.5 mm.

O.k., now you would like to get some visual tardigrade evidence? Yeeeeeees, here it is:

Waterbear Echiniscoides sigismundi, found on green algae taken from the cement wall of the harbour basin of the city of Lisbon, Portugal. Body length ca. 0.3 mm.

More about über  Echiniscoides sigismundi  in October. See you!

Literature

Marcus, Ernst: Zur Anatomie und Oekologie mariner Tardigraden.
Zool. Jahrbuch 53 (1927) p. 487 - 588.

© 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