Active volcanoes are more commonly known as harbingers of destruction, but they also may play a role in sheltering life on Earth from major Ice Age events, scientists think.
Antarctica is probably most famous for its penguins, but it’s also home to a wide range of invertebrates, more than half of them not found anywhere else in the world. The fossil records and genetic lineages of these species suggest they’ve been on the continent for some time -- millions of years -- but just how they managed to survive the deep freezes of ice ages that occurred as recently as 20,000 years ago has been a bit of a head-scratcher.
Now, an international team of researchers thinks it’s figured out the Antarctic survival strategy. The scientists looked at vast biodiversity records kept by Antarctic research camps on species of mosses, lichens and insects. When they mapped the data and ran the numbers, they were surprised to find that the closer you get to an Antarctic volcano, the more bio-diverse it gets.
But once you think about it, it makes some sense that, given a choice between wintering near a volcano and freezing, the former’s preferable.
"Volcanic steam can melt large ice caves under the glaciers, and it can be tens of degrees warmer in there than outside. Caves and warm steam fields would have been great places for species to hang out during ice ages," Australian National University researcher Ceridwen Fraser said in a statement Monday.
The extreme conditions near active volcanoes wouldn’t seem like the ideal cradle to carry organisms through cold epochs, but the hardships of living near an active volcano can be offset by the benefits of a relatively ice-free terrain.
“Despite volcanic geothermal regions typically having greater pH and mineralization of soils than nongeothermal regions, many species found in such areas are more broadly distributed and appear simply to capitalize on the warming and water availability provided by geothermal activity,” Fraser and colleagues wrote Monday in the journal Proceedings of the National Academy of Sciences.
Antarctica hasn’t always been as we know it today. Millions of years ago, the continent had subtropical forests that supported a range of wildlife, including dinosaurs. But it’s also taken colder turns as well: 20,000 years ago, it was icier than it is now.
During those deep freezes, volcano refuges may have sheltered Antarctic species through the cold weather and eventually provided the seed for organisms to spread out as the world warmed. Birds might have landed around volcanoes and inadvertently picked up seeds and spores, then flown on and dispersed them elsewhere.
The team hopes their research will also help guide future conservation efforts in Antarctica.
"We can learn a lot from looking at the impacts of past climate change as we try to deal with the accelerated change that humans are now causing," Fraser says.
SOURCE: Fraser et al. “Geothermal activity helps life survive glacial cycles.” Proceedings of the National Academy of Sciences, 10 March 2014.