Now There's An Upside To Live Volcanos: They Kept Animals From Freezing During The Ice Age
Active volcanos have gotten a bum rap. True: They are responsible for great suffering when they erupt. The terror Mt. Vesuvius let loose on Pompeii started volcanos on their downward-trending image. But volcanoes do have a benevolent side. The 16 volcanoes active in Antarctica since the last Ice Age provided life-giving heat and steam to the ancestors of the mosses, lichens and insects still living in Antarctica, helping to solve a long-standing mystery about how they survived the Ice Age to the present day, Australian and British environmentalists said in an article published Monday in the Proceedings of the National Academy of Sciences.
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How Antarctic mosses, microarthropods and nematodes (worms), which require ice-free habitat, were able survive on a continent almost completely covered in ice has long puzzled environmentalists. Geothermal sites may hold the answer. Environmentalists at the Australian National University and Australian Antarctic Division painstakingly compiled about 39,000 records of 1,823 plants and animals, creating what they say is the most comprehensive biodiversity database of Antarctic terrestrial species to date. They confirmed their hypothesis: There are more species who survived severe drops in temperatures close to volcanoes, than there are away from them. Moreover, the mosses and micro-organisms have been expanding their ranges, gradually moving out from volcanic areas since the last Ice Age. The environmentalists were able to find more evidence for plants thriving in the heat of volcanoes than for animals. "We actually find stronger evidence for the plants having survived this way," Dr. Peter Convey from the British Antarctic Survey told the International Science Times in an email interview. "Implicitly the same is expected to be true for the animals endemic on land in Antarctica, but there is a smaller amount of data suitable for our analyses for the animals."
The so-called "geothermal glacial refugia hypothesis" is not new. Lots of naturalists have raised the possibility that geothermal areas might act as long-term refuges under glacial conditions, such as a subterranean amphipod surviving in geothermally-created refuges under the Icelandic ice cap; a Patagonian crab in hot springs; bryophytes (mosses and liverworts) on the South Sandwich Islands off of Antarctica; and marine life during glacial periods 1,000 to 541 million years ago. But this is the first time that there's been a comprehensive assessment of the "geothermal glacial refugia'hypothesis," specifically as it relates to volcanoes. In their article, the enviromentalists postulated that during the Ice Ages, ice-free terrain close to active craters; lower-altitude ice-free geothermal ground; heated ground and ponds; steam fields; fumaroles (crevices in or near a volcano which emit hot sulfurous gases); and ice caves formed by geothermal steam could have existed throughout the Pleistocene era, providing habitable environments that allowed Antarctic plants and invertebrates to survive.
"These organisms have a very flexible ability to respond to environmental variation," Convey said. "Today they can live both in the 'normal' Antarctic environment, and also nearer to volcanic areas where they get some warming or protection from the worst extremes, just as they did even at the coldest Ice Age extremes." These creatures and plants are important in their own food webs, and feed on each other, he added. While on the research expedition to Antarctica, Convey and his colleagues noted how the different creatures and mosses arranged themselves around the volcanic areas. "Their distribution around these sources of heat tells you about the differences in each species' physiological tolerances," he said.
The study has implications, though miniscule, for climate change going forward. Dr Ceridwen Fraser from the Australian National University, who lead the research team, told the International Science Times in an email interview that, "This sort of research helps us understand how different plants and animals respond to climate change: which species, like mammals, can disperse long distances quickly to track shifting climate envelopes, and which cannot move fast enough but rely on micro refuges to survive, or go extinct. Of course, there's only so much looking at the past can tell us about the future, since we're seeing faster rates of warming, and heading in to warmer temperatures, than the Earth has sen in millions of years, but all clues help."
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