Scientists Amazed As Moss Frozen For 1,500 Years Started Growing Again When It Thawed Out

Drilling in the moss banks of Signy, a subantarctic island in the South Orkney Islands. PHOTO: P. Boelen

Scientists were stunned when moss which had been frozen under the Antarctic ice for 1,500 years suddenly started to grow again.

Up until now direct regeneration from frozen plant material had been demonstrated after 20 years at most. Beyond that only microbes have been capable of revival after so many years.

“These mosses were basically in a very long-term deep freeze,” says Peter Convey of the British Antarctic Survey. “This timescale of survival and recovery is much, much longer than anything reported for them before.”

The findings, announced today in the journal Current Biology, have relevance for Antarctic ecosystems and climate because mosses are primary producers on land in both northern and southern polar regions.

In the north mosses are responsible for storing most of the fixed carbon. If mosses can survive in this way for such long periods of time, then regrowth once the ice retreats wouldn’t require long-distance, transoceanic colonisation.

Convey and his colleagues primarily study polar moss cores because they provide an archive of past climate conditions.

The researchers use them to assess growth rates over time and as proxies to reconstruct aspects of the environment and change over time.

The oldest moss banks of the type under study in the Antarctic date back almost 6,000 years. The one the researchers focused on in the current work is nearly 2,000 years old at its base.

The researchers weren’t sure that mosses frozen for more than a decade or two would remain viable. When they began to see the 1,500-year-old mosses start to regrow, it came as a surprise.

“We actually did very little other than slice the moss core very carefully,” Convey says.

To make sure not to accidentally get any other life forms in the mix, the scientists placed the sliced and seemingly lifeless mosses in an incubator environment at a normal growth temperature and light level.

New shoots of the parent species began to appear.

“The potential clearly exists for much longer survival — although viability between successive interglacials would require a period of at least tens of thousands of years,” the researchers write.

Drilling in the moss banks of Signy. PHOTO : P. Boelen

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