The bdelloid
rotifer is awake – and we're going to need to buy some more birthday candles.
For the past
24,000 years, the multicellular microorganism has been snoozing in Siberian
permafrost, having become frozen in the Arctic ice right around the same time
in history that humans first ventured into North America during the Upper
Paleolithic era, otherwise known as the Late Stone Age.
Video
released by the laboratory captured the wriggling movements of the tiny
microorganism as it reemerged from its frozen state. (Soil Cryology Laboratory)
A bdelloid
rotifer is a freshwater creature that can be found around the world, measuring
too small to see with the naked eye at 150 and 700 μm, the unit for micrometers
which are used to measure microns. For comparison, the thickness of paper
measures 70 to 180 μm.
Not only did
the animal come back to life from its frozen nap, but it also successfully
cloned itself multiple times with an asexual reproduction form known as
parthenogenesis.
The bdelloid
rotifer is a tiny freshwater creature that can be found around the world. It is
about the thickness of a piece of paper or just a hair larger. (Soil Cryology
Laboratory)
The
remarkable discovery has experts raising new questions about the mechanisms of
cryptobiosis, the state in which metabolic activity is reduced to an
undetectable level without disappearing completely.
The finding
was made by researchers from the Soil Cryology Laboratory in Pushchino, Russia,
who were astonished to discover the microorganism alive and well in a soil
sample, taken from permafrost in northeastern Siberian. Radiocarbon dating
found the specimens to be about 24,000 years, the authors wrote in their
publication on Cell.com.
The
permafrost samples were taken from the Alazeya River, which flows from Siberia
into the Arctic. The researchers explained that they are confident that
organisms as large as the bdelloid rotifer wouldn't have been able to move
through ice-cemented ground.
"Thus, no significant vertical movement could have occurred in the studied sediments, and therefore the isolated microbes were likely trapped in permafrost at the same time as the radiocarbon-dated organics," the study reads, before adding that age analysis data from the University of Arizona AMS Laboratory shows the material to be between 23,960 and 24,485 years old.
Stas
Malavin, an author in the study, said in a press release that the findings are
a big step forward for researchers in moving from the preservation of
single-celled organisms to ones with a gut and brain.
“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.
But the
team's findings are still a revolutionary addition to the short list of
organisms that have been found to be able to survive such extraordinary
timespans.
Previously,
a pair of prehistoric nematode, otherwise known as roundworms, were discovered
and successfully revived in Russia. The worms were dated to have been between
30,000 and 42,000 years old.
Similarly,
numerous prehistoric plants and mosses have successfully regenerated after many
thousands of years trapped in the ice, the press release said. However, none of
the previously discovered specimens were nearly as complex as the bdelloid
rotifer.
The melting
of permafrost has allowed researchers to study more and more prehistoric
organisms in recent years, including a number of much larger mammals. In 2016,
a gold miner in Canada hit a layer of thawing permafrost and unearthed a
doglike specimen. Researchers in December concluded that it was actually a
57,000-year-old, Pleistocene gray wolf puppy, the most perfectly preserved
animal of its kind.
"The hope is that insights from these tiny animals will offer clues as to how better to cryo-preserve the cells, tissues, and organs of other animals, including humans," the press release wrote.