7 wonders of the soil
The tiny and incredibly hardy water bear is often found in the film of water in soils, but can survive anywhere – ocean sediments, below the Antarctic ice, in mosses, in boiling hot geothermal springs, even outer space. Also known as tardigrade or moss piglet, the water bear does resemble a bear, but has eight legs and is only about the size of a full stop. Its segmented body has a brain, a digestive system (it mainly feeds on plants or bacteria, though some are carnivorous) and sexual organs, and it is prey to nematodes, amoebas and other tardigrades. Scientists are studying the water bear’s ability to enter a state of metabolic standstill – called cryptobiosis – in the face of environmental stressors such as lack of water or oxygen, low temperatures and radiation, sometimes for as long as 120 years. It may hold clues to the preservation of tissues, cells and vaccines without refrigeration.