A microscopic animal, frozen for 24 thousand years in Siberian ice, has come back to life and managed to feed and reproduce. Now we’re trying to figure out how it did it.
Tardigrades are known in the animal kingdom for their extraordinary resilience, despite their microscopic size. Like these record-breaking invertebrate creatures, the so-called rotifers bdelloidei also manage to survive starvation, desiccation, freezing, and even very low oxygen conditions. Now, scientists have managed to bring some specimens back to life after they were frozen in Siberian ice for over 24 thousand years.
The incredible result was published in the scientific journal Current Biology. A peculiar characteristic of the tiny bdelloid rotifers is to be able to resist extremely low temperatures: already in the past they have been seen surviving from 6 to 10 years at temperatures as low as -4 degrees Fahrenheit, equal to -20 degrees Celsius. Now it has been realized that this ability is even more amazing. Researchers took samples of permafrost about 10 feet deep and slowly heated the sample, which resulted in the resurrection of several microscopic organisms including these tiny animals with enviable temperament.
As with the case of the immortal jellyfish, the longest-lived animal on Earth, we are faced with what appears to be a miracle of nature, as pointed out by Stas Malavin, co-author of the study and a researcher at the Cryology Laboratory at the Pushchino Scientific Center for Biology in Russia:
Our report is the strongest evidence we have to date that multicellular animals could endure tens of thousands of years in cryptobiosis, a state of almost completely arrested metabolism.
Still more incredible is to think that when the collected samples were brought to the lab, they not only thawed, but the rotifers reproduced asexually using a process called parthenogenesis. They were also able to feed themselves.
The team specializes in studying frozen organisms in permafrost and was very careful in extracting this sample. Given the resilience of these animals, it was indeed important to make sure the sample was not contaminated by newer layers. The study found that rotifers can resist the formation of ice crystals that occur during slow freezing, suggesting that they have some mechanisms to protect all parts of their bodies from the extremely cold temperatures.
For now, the process remains partly mysterious, but it is clear that something extremely peculiar must be happening in these tiny animals as they are slowly frozen. Malavin and his will continue to study the permafrost to see if more animals with these abilities exist and to find out what mechanism comes into play to make a frozen organism survive for thousands of years.
Andrea Guerriero