(CN) --- Some frozen organisms can survive for centuries, but new research published Monday dates a collection of living microscopic rotifers uncovered from the permafrost in Siberia to be more than 20,000 years old.
"Our report is the hardest proof as of today that multicellular animals could withstand tens of thousands of years in cryptobiosis, the state of almost completely arrested metabolism," explained Stas Malavin at the Institute of Physicochemical and Biological Problems in Soil Science in Pushchino, Russia in a statement.
The study was published Monday in the journal Current Biology.
Commonly described as wheel animals, rotifers are tiny planktonic organisms found in both fresh and salt water. The international team of researchers found the Bdelloid Rotifer from samples collected with a slow rotating drill from 11 feet underground in the middle of the Alazeya River in 2015. The permafrost maintains a freezing cold temperature of 14 degrees Fahrenheit year-round.
Several dozen rotifers were found among the ice. Once thawed, the rotifers fed on bacteria found in the sample and reproduced asexually into clonal populations.
Analysis from accelerator mass spectrometry dated the sample between 23,960 and 24,485 years old.
"Clearly, the ancient rotifer is capable of surviving a relatively slow freezing process that allows ice crystals detrimental for cells to form,” the researchers wrote in the paper. “In combination with its occurrence in permafrost, this suggests that the discovered Adineta sp. has effective biochemical mechanisms of organ and cell shielding necessary to survive low temperatures."
"This discovery is of great interest not only for evolutionary biology but also for practical purposes of cryobiology and biotechnology," the researchers concluded.
Though a rare find, the rotifers are not the first organism found to survive deep freeze. Researchers point to the stems of Antarctic moss which have been regrown after being under ice for 400 years, as well as single-celled nematodes which had been revived from sediments over 30,000 years old.
"The takeaway is that a multicellular organism can be frozen and stored as such for thousands of years and then return back to life --- a dream of many fiction writers," Malavin said in the statement. "Of course, the more complex the organism, the trickier it is to preserve it alive frozen and, for mammals, it's not currently possible. Yet, moving from a single-celled organism to an organism with a gut and brain, though microscopic, is a big step forward."
Researchers hope to further understand the biological mechanisms that protect rotifers from ice while freezing, according to a press release, in hope of learning how to “cryo-preserve the cells, tissues, and organs of other animals, including humans.”
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