Tardigrades – invincible organisms that survive even in vacuum

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Tardigrades – invincible organisms that survive even in vacuum

2016-3-1 UPDATE

Tardigrades - invincible organisms that survive even in vacuum

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Invulnerable

The long chain of evolution sometimes produces incredibly strange results.
How about the unyielding survival power of the tardigrades?

Science fiction and horror movies sometimes feature invulnerable monsters that simply refuse to die, no matter what damages are inflicted upon them. What if I told you that such indestructible creatures really exist? Because, as a matter of fact, they do.

They are called tardigrades and are about 0.5 to 1 mm long. Because the way they slowly walk on their four pairs of legs resemble the gait of a bear, they are also known as water bears. They sustain themselves by boring holes in plants and sucking out the cell sap.
They live practically everywhere on Earth. In Japan, they can be found in the mosses of marshlands, or among the water weeds of ponds. When I say “practically everywhere on Earth,” I mean that literally. Tardigrades can live anywhere, from the Arctic to the tropics, from high in the Himalayas to deep in the ocean. It is because of this ability to adapt themselves to the harshest conditions that they are known as indestructible organisms.

Temperature-wise, neither heat of 150 degrees Celsius nor a cold of minus 270 degrees, close to absolute zero, will kill them off. There are tardigrades in the water of hot springs. In draughts, they survive by gradually reducing their bodily moisture down to 3%, and then return to normal as soon as they come back into water. Almost like freeze-dried instant food. They also have an astonishing capacity to withstand radioactivity, and pass through powerful X-rays without any hitch. Pressure that no other living beings could take is no problem for the tardigrades. They even survive in the vacuum of outer space. They truly seem genuinely invulnerable.

But why are they so tough? When the external conditions get too nasty, the tardigrade’s body changes into a barrel-shape. Once shaped like a wine barrel, it enters a state of cryptobiosis.
By transforming themselves like this, they are able to suspend their metabolism almost completely and wait until conditions improve. What extraordinary kind of evolutionary process could have made them develop such an ability is an infinitely interesting question, but actually they are not the only ones. There are other organisms as well that share this miraculous survival power.
For example, the sleeping chironomid (Polypedilum vanderplanki) is a kind of fly that lives in Africa, and just like the tardigrades, it enters a state of cryptobiosis in times of draught and waits for water to return.

The analysis of the DNA of such organisms is making rapid progress. And if we could apply the results to ourselves… perhaps one day a real Superman will be born.

This Japanese site has some photographs of tardigrades: