A rock wall (I) - or: holiday time
About 10 years ago we presented instructions about
How to find tardigrades .
We didn't go much into detail with respect to the recommended locations, just
mentioned that the typical tardigrade home is a moss cushion.
Starting from 2008 we described marine tardigrade species and the respective locations,
e.g. Echiniscoides sigismundi
living on Enteromorpha algae at a Lissabon beach, Batillipes mirus
from a sand sample of the Kieler Föhrde, Germany, and some bizarre marine tardigrades from a beach in Croatia,
e.g. Florarctus sp. ,
living at a few meters depth at the ground of the ocean.
This issue will provide some supplementary hints which will hopefully help
the beginner to collect "good", i.e. densely inhabited, moss samples.
But in any case it must be pointed out before that there is no need to devastate
the landscape. The volume of a walnut is perfectly sufficent in order to gain
an overview about the tardigrade population of given location. This sample size
will cover the ground area of several petri dishes. Please keep in mind that the mosses
are growing slowly - so by taking bigger samples you are in danger of leaving ugly traces
at some locations which might remain visible for years.
As a rule the most suited mosses will be those which undergo a regular
wet/dry cycle, either becoming wet by dew or rain. Furthermore they should become
thoroughly dry from time to time - so sun-lit locations should be preferred.
A good choice are mosses on the walls of cemented brooks and rivers,
mosses on old roof tiles - the older the better, mosses on stone or rock surfaces.
It is well known that the tardigrade diversity is increasing when moving
from the aequatorial regions to the south or north pole of the earth.
And it is important to keep in mind that tardigrades have no blood circulation,
just rely on oxygen diffusion. So oxygen lack is omnipresent. Tardigrades enjoy
cool areas (high oxygen content in water) and windy areas (much oxygen and
few bacteria). As a consequence locations with constantly high humidity or
high temperature will be less ideal as a tardigrade home. Those of you
who are not willing to travel to the poles can be consoled. You will find
lots of tardigrades on most mountains:
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