Natures wonders: how tardigrades survive (Introduction)

by David Turell , Wednesday, October 12, 2022, 14:55 (771 days ago) @ David Turell

Frozen survival:

https://www.sciencealert.com/tardigrades-can-survive-frozen-oblivion-by-pausing-their-b...

"To withstand freezing to death the cuddly-looking water bears enter an extreme form of hibernation called cryobiosis. In this state their metabolic activity basically comes to a standstill.

"It now turns out their metabolism isn't the only process set to 'pause'.

"University of Stuttgart biologist Jessica Sieger and colleagues exposed a bunch of Milnesium inceptum tardigrades to alternating weekly periods of freezing at −30 °C (−22 °F) and feeding at 20 °C (68 °F), until they died. Another group was maintained at room temperature.

"Amazingly, out of a total of 716 tardigrades, those that were periodically frozen lived twice as long as the control group. The longest lived for 169 days, 94 of those spent at room temperature, while the oldest tardigrade in the control group reached 93 days.

"All up, both groups spent the same amount of time actively alive, demonstrating that the tardigrade's biological aging was dramatically slowed, if not halted altogether by cryobiosis. This, the researchers say, confirms the 'sleeping beauty' model of cryobiosis on the animal's biological clock, as opposed to other models that suggested aging is either slowed or continues as normal.

"'During inactive periods, the internal clock stops and only resumes running once the organism is reactivated," explains zoologist Ralph Schill, also from the University of Stuttgart. "So, tardigrades, which usually only live for a few months without periods of rest, can live for many years or even decades."

***

"Tardigrades have been recovered after being frozen for more than 30 years, still alive and fertile. But their suspended animation is not a foolproof system.

"Freezing safely is a complicated physiological process. Death can occur instead, if freezing happens too fast – not allowing certain biochemical processes to complete quickly enough, the researchers explain.

"Insufficient energy storage can be another factor that can go very wrong. Previous studies have demonstrated that entering and exiting their profound sleep state uses the energy stored in cells within the body cavity of the chonky animals.

Comment: more amazing facts about Tardigrades. Why were they created? They fit a role in an ecosystem