The most exotic locations where we can find tardigrades

In the  previous issue  we have discussed typical places close to your home where you can expect to find terrestric tardigrades. Further subjects were how to find the tardigrades and how to look at them under the microscope in a non-destructive style.
Now we will concentrate on the more unusual and surprising water bear habitats: Evelyn Du Bois-Reymond Marcus reports in Studies on the Fauna of Curaçao  about a tardigrade found at "lat. 43° 4´ N, long. 31° W". Let's have a look at the globe to see where this is:

We become aware (left side) that the geographic data by Evelyn Du Bois-Reymond Marcus refer to a location in the middle of the Atlantic Ocean. The map on the right side reveals that this location appears to be situated about 100 km north of the Azores und about 2000 km west of Portugal, in the middle of the Ocean. On the other hand, Kaestner explains in his zoological compendium that tardigrades live in water, but are definitely unable to swim!
How is it possible then that an approved non-swimmer lives on top of such a huge amount of sea water? Du Bois-Reymond Marcus has the explanation in her article. The water bear under consideration was found on floating  Sargassum algae !
Travelling on the back of the algae the water bear has left his companions at home in Mexico and is going to explore the rest of the world. Its colleagues at home will have to find a pigeon carrier in order to compete. Of course the regular movement of water bears, in particular of terrestric tardigrades in isolated moss cushions, is much slower. Kinchin quotes a maximum value of 17.7 cm/h for the tardigrade Macrobiotus hufelandi (values measured by Ramazzotti and Maucci).

In contrary, the water bear  Coronarctus tenellus  was found in the Indian and Atlantic Ocean, in depths between 400 und 3700 m (!) (Kinchin, p. 94).
Echiniscus testudo  lives on Bear Island (nomen est omen) and in Paris (Marcus reporting).
The green water bear  Echiniscus viridis  seems to be not as uniquitous and was found e.g. on the Sandwich Islands and Oahu (Marcus).
Thermozodium esakii  was found by Rahm within a hot fountain near Nagasaki in 1937, afterwards nevermore. Kinchin  comments on this special case: "A third class of tardigrade, the Mesotardigrada, was established on the basis of the description of Thermozodium esakii  by Rahm (1937). This species was discovered in a hot spring near Nagasaki, Japan. However, since neither type material nor type locality has survived to the present day, and no other species of mesotardigrade has yet further been described, this poorly documented group will not be discussed any further here."

The cosmopolitan Milnesium tardigradum  was found at the following locations by Marcus : Spitzbergen, Novaja Semlja, Norway (northern), Lapland, Finland, Southern-, Middle- und Northern Sweden, Southwest Sweden, Gotland, Bornholm, Faröer, Shetland Islands, Orkney Islands, Scotland, Ireland, The Netherlands, Kiel, coast of Mecklenburg, Rügen Island, near Berlin, Brandenburg, Taunus, Southern Germany, the Black Forest, Swiss Jura, Swiss Alps (up to 4000m), Lake Genova (up to 40 m in depth), Rhaetian Alps, Lake Lüner, Vallüla (2800m), near Paris, Gibraltar, Lake Como, Bellagio, Bukowina, the Himalajas (6000m (!)), Sumatra, Java, Eastern Lombok, Teneriffa, Australia, New Zealand, Canada, Peru, Paraguay, Chile, Tierra del Fuego, the Falklands, Southern Georgia ...
It is no surprise that this species can be found also in the cities, sometimes as the most abundant species.

And there is one more fascinating extreme reported from France:

Record under the ice

During the campaign Islandsis 98 the French "Glacieronaut" Janot Lamberton established a new record when climbing down 202 meters into a Greenland glacier. He went down to the core of the glacier via a short-lived and extremely deep pit within the ice (a so-called "moulin") which had been formed previously by a temporary underground river. Besides this record allowed to get further insight into the lives of the tardigrades, small (1/10 mm long) organisms which can survive freezing and thawing in the polar winter. If we were able to understand the basics of this process it might used e.g. as a valuable method for the preservation of human organs for transplantations (translation by the author).

Source:  http://www.diplomatie.gouv.fr

In the next issue we will discuss tardigrade eggs some of which are really bizarre. 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.

Literature:
Alfred Kaestner: Lehrbuch der speziellen Zoologie. 3. Auflage, Bd. I, Teil 1, S. 596.
Ian M. Kinchin: The Biology of Tardigrades. Portland Press, London 1994.
Evelyn du Bois-Reymond Marcus: Tardigrada from Curaçao, Bonaire and Los Testigos.
    Studies on the Fauna of Curaçao and other Caribbean Islands X (1960) S. 52-57.
Ernst Marcus: Bärtierchen (Tardigrada). Gustav Fischer Verlag, Jena 1928.

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