Tardigrades have been found everywhere in Earth’s biosphere, from the highest mountaintops to the deepest sea and from tropical rainforests to the Antarctic. There are sure to be some, somewhere, in the reserve’s ponds, going quietly about their business.
Tardigrades are a phylum of tiny eight-legged aquatic animals, no longer than 1.2mm. They are nicknamed water bears or moss piglets and are believed to be the hardiest and toughest creatures on earth; they can withstand the most extreme and demanding environments by dehydrating and going into a state of frozen animation known as cryptobiosis.
Tardigrades have survived being boiled in water and being frozen; in fact, there is anecdotal evidence that they can survive being immersed in liquid helium, just 1C above absolute zero. They can withstand pressure equal to six times the pressure of sea-water at a depth of 10,000 metres and in 2007, tardigrades were sent into space to orbit the earth on the outside of a rocket for 10 days. When the rocket returned to Earth, it was found that 68% of the tardigrades had survived not just the 10 days in space, but re-entry into the Earth’s atmosphere when the rocket’s exterior surface was exposed to temperatures in excess of 1000°C
We know of more than 1,150 different species of tardigrades, and about 20 more are found each year. If we manage to make Planet Earth uninhabitable for most of its species of life (including ourselves) we can be almost certain that the tardigrades will be somewhere among the survivors.
Header image: SEM image of Milnesium tardigradum by Schokraie E, Warnken U, Hotz-Wagenblatt A, Grohme MA, Hengherr S, et al. (2012), (CC BY 2.5) Wikimedia Commons
If the tardigrades inherit Earth, what will they evolve into over the next fifty million years?
Let’s hope they get to keep the six legs and the capacity for cryptobiosis.