High in the Canadian Arctic on Baffin Island, beneath 10 meters of water and many more of mud, sits a refrigerated archive of Earth’s past life. The deep sediments in a small lake called CF8 hold ancient pollen and plant fossils. But it now appears that the mud harbors something else: ancient DNA from as far back as the Eemian, a period 125,000 years ago when the Arctic was warmer than today, left by vegetation that otherwise would have vanished without a trace.
“We feel confident that we are getting authentic results,” says Sarah Crump, a paleoclimatologist at the University of Colorado in Boulder who is presenting the work here this week at the annual meeting of the American Geophysical Union. She acknowledges the finding needs to be confirmed. But if it holds up, it could open a window on the ecosystems that flourished in the high Arctic at a time when temperatures were a few degrees warmer than today. It would also attest to the power of sedimentary DNA, as it’s called, to show how Arctic plants responded to past climate shifts—hinting at how they might respond in the future. “We are now at the point that this is a really useful signal for reconstructing biodiversity,” says Ulrike Herzschuh, a paleoecologist at the Alfred Wegener Institute in Potsdam, Germany, who uses the technique to study how the larch forests of Siberia in Russia reacted after the end of the last ice age some 12,000 years ago.
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