Tardigrades (aka “moss pigs”) are renown for their hardiness; being able to survive extremes of temperature, dehydration and radiation (including space). They do this by entering a state of suspended animation, known as cryptobiosis. They range in size from 0.1 to 1.2 mm long.

What we did:

  1. Collected some moss from our yard – off some bricks and from soil surrounding a plant in a pot.
  2. Added some distilled water, and left overnight.
  3. Placed the sample under a stereo microscope at 40x magnification. You could look with a hand lens, but it is much more difficult to look systematically, and a lot more tiring for your eyes.
  4. Shone some light from the side, using an LED torch (since the light that comes with our microscope tends to heat samples up quite quickly, often to the detriment of the sample).
  5. Spent some time just looking, mainly focused on the bottom of the dish rather than the moss itself.

What we found:

  • There were a lot of small white or transparent living things in the sample. Even if you dont find tardigrades, you are almost certain to find some animal life in your sample.
  • We did find some tardigrades, stumping around.

I haven’t mastered using the camera with the microscope yet, but this gives some idea of what we saw:

Te Papa note that there are 90 species of tardigrade in NZ, and provide some pictures from their collection. There are some nice, clear, close-up photos on the BBC site.

Next time we will:

  • Try collecting from some other sites, including lichens, liverworts and soil.
  • Get the camera/microscope set up working more smoothly.
If you want to have a go yourself, we found useful information here.