Scientists in Japan have successfully thawed and revived tardigrades that were recovered from Antarctica in November of 1983. The remarkable scenario adds to the reputation of tardigrades as being the worlds most durable organism.
Two individual tardigrades and a separate egg were retrieved in Antarctica over 30 years ago and stored at about minus 20 degrees Celsius. In May of 2014, all the samples were successfully thawed and revived, marking the longest record of survival for tardigrades as animals or eggs. Surprisingly, one of the tardigrades and the new hatchling from the egg repeatedly reproduced, demonstrating an incredibly speedy recovery from cryptobiosis.
Tardigrades, also known as water bears, are eight legged, water dwelling, micro-animals. They’ve been found anywhere from the highest mountain tops, to the deepest depths of the ocean. They are likely the most durable animal known, being able to go without food or water for over 30 years.
Given its reputation as a survivor, these new results are still surprising even for the mighty tardigrade. The previous longest record for revival after long-term storage was only 8 years. Tardigrades have the unique ability to shut down metabolic processes under certain conditions such as freezing, a state known as cryptobiosis.
Both of the revived tardigrades began moving their 4th set of legs on the first day after re-hydration. For one of the subjects, the recovery process took about two weeks for the animal to begin crawling and eating. However, the other tardigrade ended up dieing 20 days after re-hydration. Just after two weeks, the surviving tartigrade laid 19 eggs, of which 14 hatched successfully. The juvenile that hatched from the revived egg ate, grew, and reproduced without any obvious abnormalities.
They study is one of the first to observe in detail the recovery process and subsequent reproduction of revived tardigrades – previous studies had generally not reported on these. Scientists will now look to study the tardigrades DNA in hopes of finding any possible damage that may have accumulated over the 30 years of cryptobiosis.
“Our team now aims at unraveling the mechanisms underlying the long-term survival of cryptobiotic organisms by studying damage to tardigrades’ DNA and their ability to repair it.” said Megumu Tsujimto, lead author of the study published in the journal Cryobiology.