Moss Survives 1600-Year Deep-Freeze In Antarctica
Moss that had been frozen in Antarctic permafrost for up to 1,697 years ago came back to life after ecologists put in an incubator in a laboratory, they said in a report Monday. Till now, the oldest frozen plant material that could be regenerated in this way was only 20 years old. The longevity of the moss was unexpected, Peter Convey, an ecologist from the British Antarctic Survey and University of Reading told the International Science Times. "We were not surprised moss could survive frozen for more than 20 years, but to get clear growth from stems over 1,600 years old was a bit more surprising." The opportunity came as the happy offshoot of another project where the econologists were looking at the preserved pigments of frozen moss. "It was a 'blue sky' question, 'how long does a moss stay alive for?'" Dr. Convey said.
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The core samples of moss were taken from permafrost 30 centimeters deep. The mosses' shoots were still intact and alive at the point they become incorporated in the permafrost. All the ecologists had to do was put the mosses in an incubator at a normal growth temperature and light level, and new shoots of the parent species began to appear. The potential exists for much longer survival -- although viability between successive interglacials would require a period of at least tens of thousands of years.
The resurrection of metabolism under extremely low temperatures -- called cryptobiosis -- is qualitatively no different from what plants do in the lower latitudes when they come back in the spring. In permafrost, and active layer monitoring studies in this area indicate around -8 to -10 degrees celsius -- the temperature will vary with depth the base of the active layer will be around 0 degress centigrade in summer. "The moss wasn't really dead, more that it has been in limbo in a long term deep freeze," Convey said.
It's conceivable that other plants could survive in this manner as well. For Antarctica, which is short on flowering plants (two) that would mean other mosses and possibly lichens.vConvey said. The moss is a so-called "primary producer" in the Antarctic; a photosynthesising organism that fixes carbon dioxide from the atmosphere. Mosses store most of the fixed carbon, a crucial role of mosses as primary producers across very large areas of high northern latitudes in particular: The same is true in the south, but there's less ground there) Mosses are typically very slow to decay, so once carbon is fixed in them, it takes a long time for the CO2 to be released to the atmosphere. Thus, while there is much concern about permafrost melting and allowing decay to release CO2 to the atmosphere, tif mosses respond to climate change by growing more rapidly, then they will provide a means of taking up some CO2 from the atmosphere too.
The ecologists are now trying to see whether they can achieve regrowth from some older cores, as well as different species. "The most important next step will be to see how generally the finding applies," Convey said. The frozen moss findings have implications for climate change in general. "As climates warm and ice recedes in polar and alpine regions," Convey said, "survival in situ means that recolonization and community development will be influenced by local survival, and not as previously assumed require colonization from a much longer distance."
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