Tale of the Frozen Water Bear
A water bear, or moss piglet or tardigrade, is a tiny animal that lives among mosses, and has a unique ability to survive some of the harshest conditions on earth. They are able to survive extreme temperatures as low as -328 °F and up to 304 °F, freezing and thawing, changes in salinity, lack of water, radiation, lack of oxygen, boiling alcohol, toxic chemicals, as well as low and high pressure. As a result scientists have run numerous tests and experiments on these resilient creatures and have uncovered some interesting findings.
Acutuncus antarcticus, an individual representing the SB-3 strain, showing Chlorella sp. inside its stomach. Courtesy of Sciencedirect.com
The Experiment
Thirty-one years ago on November 6, 1983, Hiroshi Kanda took several samples of the Tardigrade organisms and their environment, and put them in a freezer at -4 °F. One sample was chosen on May 7, 2014 and set to thaw for twenty four hours. The sample was then soaked in water for another 24 hours.
When a water bear dies, it assumes what is called the International Tardigrade Posture of death. This posture is one of full extension. Two of the organisms had not yet assumed said position and were named Sleeping Beauty-1 and Sleeping Beauty-2 (SB-1, SB-2). An egg was also retrieved from the sample labeled SB-3. In addition, all three were put on individual culture plates and given food and water in the form of Volvic, a French mineral water, and Chlorella, a type of algae.
Slowly the tardigrades began to show signs of life.
Source: Sciencedirect.com
SB-1 was the most successful of the three revived, producing a total of 19 eggs by day 45. Fourteen of the eggs actually hatched. SB-2 recovered in much the same way, but unfortunately died on day 20. SB-3 hatched on the sixth day. It then proceeded to reproduce asexually after eight days of its life and, by the thirty-eighth day, SB-3 had produced fifteen eggs of which seven hatched. SB-3 died on day thirty nine.
Scientists had only discovered the longest lifespan of a dried out tardigrade before this experiment, not a frozen one. The longest lifespan was eight to nine years. Scientists believed that this was because exposure to air allows for oxidative damage, a process akin to rusting metal. However, scientists also believe that the process can be slowed or even completely eliminated by freezing. Scientists concluded the longer the organisms are frozen, the longer the recovery process.
Source: Nasa.gov
What Does This Mean for Humanity?
These experiments aren’t simply to see just how capable the tardigrade is. This research could potentially apply to other organisms such as humans. Obviously, we are several lifetimes away from Star Trek-level cryogenics, but scientists are always searching for new ways to prolong our survival.
“We want to unravel the mechanism for long-term survival by looking into damage to tardigrades’ DNA and their ability to repair it.”
-Megumu Tsujimoto, a postdoctoral researcher
The water bear and its unique abilities for survival may very well one day be the key to keeping the human race alive. For now, there is much more research and experimenting to be done. But these resilient creatures have proved themselves to be up to the challenge.
Here you can see the experiment itself and all results in greater detail.
Resources for Educators
- http://www.pathfinderscience.net/tardigrades/
- http://tea.armadaproject.org/activity/tea_activity_anhydrobiosis.html
- https://sun.iwu.edu/~tardisdp/lessonplan.html
By Bethanny Jones