The microscope has opened up unlimited opportunities to study bizarre and fascinating microscopic life. Tardigrades are primitive arthropod microorganisms often referred to as “moss piglets,” or “water bears.” Tardigrades are classified in the phylum, Tardigrada , or “slow walker,” seeing as tardigrade move slowly under the microscope.
Tardigrades are considered polyextremophiles, meaning that they can withstand extreme environments and temperatures anywhere from -273 ° C (close to absolute zero) to 151 ° C and can undergo nearly 1,000 times more radiation exposure than other living organisms. Tardigrades have survived the vacuum of space and have gone decades in the absence of water.
The nickname, “water bear” is derived from the observation that tardigrades walk with a gait similar to that of a bear. For the most part, tardigrades are plant eaters, with only a few species being predatory.
Tardigrades exist in more than 1,000 different species and have a wide dispersion. Tardigrades have been found in the arctic regions, the equator and nearly everywhere in between. Tardigrades have been observed on moss, lichens, beaches, bodies of fresh and salt water, hot springs, under sheets of ice, and in soil.
Tardigrades have a unique ability to halt their metabolic systems which allows them to enter into a state of cryptobiosis (a frozen state of being), until favorable environmental conditions return. During cryptobiosis, tardigrades can eaisly withstand extreme pressures, dehydration, temperature, radiation, and intense environmental toxins. Tardigrades are, to say the least, hardy little organisms. Here are my procedures for the collection and viewing of tardigrades.
One of the easiest ways to find tardigrades is by going outside and collecting a few tufts of moss or lichen from around your home. Use scissors to cut only the green parts of the moss off from the rocks or the soil on which it grows; the dirt may clutter up the viewing slide while under the microscope. Submerge the bits of moss in a dish of spring or rainwater. Avoid using tap water.
Leave the moss and water to sit overnight and the next day, drain the excess water. Take the clumps of moss and squeeze the remaining water into a clean dish. Place droplets of this water onto a clean slide and view under a microscope on a power setting of 40X. Look for the tardigrades – they will be the largest organisms in view and they will resemble small bears or pigs with eight legs!