In what they are calling the most extreme case of frozen plant regeneration ever documented, scientists are claiming to have regrown shoots of Antarctic moss that were trapped beneath layers of ice and frost for more than 1,500 years.
In a paper published on Monday in the journal Current Biology, scientists from the British Antarctic Survey and the University of Reading, in England, said the regrowth occurred in a sample taken from a gigantic bank of moss on remote Signy Island.
"These mosses were basically in a very long-term deep freeze," co-author and terrestrial ecologist Peter Convey wrote. "This timescale of survival and recovery is much, much longer than anything reported before."
Cryptobiosis, or "hidden life", describes the ability of some invertebrates, plants and microbes to enter suspended animation when faced with environmental extremes, such as intense cold or lack of moisture. It was thought they could survive like that for no more than a couple of decades.
"Here we show unprecedented millennial-scale survival and viability deep within an Antarctic moss bank preserved in permafrost," Convey wrote.
The moss, Chorisodontium aciphyllum, can grow more than three metres into high banks in the maritime Antarctic. New growth occurs at the surface, while lower levels become part of the permafrost, researchers say.
During a visit to Signy, researchers used a drill to remove a core sample of moss roughly 2.5cm wide and 1.2 metres long and transported it to the University of Reading for analysis.
Researchers radio-carbon- dated moss shoots at the sample's base and said they were between 1,533 and 1,697 years old. They also placed sections under growing lamps and misted them with water. Each showed new growth, but at very different rates.
"The length of time required before growth became visible increased with depth," the authors wrote, with growth visible at more than 7.5cm of depth after 27 days, and at 1 metre after 55 days. Growth at the very bottom was visible after just 22 days.
"The potential clearly exists for much longer survival," the authors wrote.