- Education and Science
Tardigrades: The Conquerors of All Environments
What is a tardigrade?
A tardigrade, also known as a water bear, are eight legged microscopic creatures that can survive some of the most extreme of temperatures and conditions. For example, they can survive in outer space without protection. If humans were to go into outer space with no protection, we would experience a time period of 15 seconds were our lungs would deflate, our skin would blow up like a balloon, and our blood would boil. Even after all that, radiation would rupture and rip apart the DNA in our cells. This creature can survive all of this and more.
The tardigrade, at 1 mm long, can survive even harsh environments on Earth. They can survive temperatures up until Absolute Zero (0 degrees Kelvin, -273 degrees Celsius, -459.4 degrees Fahrenheit), huge amounts of radiation, and scalding hot springs. They can even live without water for over a decade!
How can a tardigrade withstand such environments?
In 1922, German scientist H. Baumann discovered that when a tardigrade dries out it retracts its head and its eight legs. It then goes into a period of suspended animation, similar to death. Shedding the water in its body, its metabolism slows down .0001%. It can stay like this for years, until it comes into contact with water. We know that some species, like nematode worms, yeast, and bacteria make a sugar called trehalose to survive desiccation. this sugar forms a protectant around water molecules, to prevent them from expanding. Tardigrades, however do not use this 'trick' to survive desiccation, and we have yet to discover how tardigrades protect themselves from low water levels for decades, without dying.
We have also tested tardigrades exposure to extreme temperatures. When a tardigrade is in its "tun" state, meaning the state in which it is in suspended animation, can survive very low and very high temperatures. In 1842, a scientist by the name of Doyere heated a tardigrade to a temperature of 125 degrees Celsius (257 degrees Fahrenheit), for a couple of minutes. In the 1920s, Gilbert Franz Rahm, brought tardigrades to life after heating them to 151 degrees Celsius (303.8 degrees Fahrenheit) for 15 minutes. Rahm also exposed tardigrades to very low temperatures. They all come back to life when contacted with water after being exposed to -200 degrees Celsius liquid air for 21 months, -253 degrees Celsius in liquid nitrogen for 26 hours, and -272 degrees Celsius for 8 hours. We also know that tardigrades can survive temperatures up to -272.8 degrees Celsius, just above Absolute Zero (the temperature wh
ich the electrons in an atom cease to move). They can survive these low temperatures, even though the lowest temperature recorded on Earth was -89.2 degrees Celsius in 1983; way above their tolerance level.
In 1964, scientists exposed tardigrades to high, even lethal doses of radiation and found that these creatures still survived. Experiments show that they can survive high doses of gamma and UV rays, even when they aren't in their tun state.
Even though the tardigrade seems to be a superpower, it might not help other animals to mimic them. When in their tun state, tardigrades are not moving, easy to be eaten by a predator. For other animals, this wouldn't help them at all.
Tardigrades are creatures that have live for 500 million years, and are still living today, yet scientists have yet to unravel the mysteries of how exactly a tardgrade can withstand these overbearing temperatures.