How does life survive during ice ages? Scientists unravel mystery.
Nature, it seems, has its ways of dealing with crises.
During ice ages, when temperature on the Earth dropped significantly and large areas of the planet were covered with ice sheets, it was volcanoes that prevented a large number of species from freezing, shows new research.
An international team of researchers, who published a paper titled "Geothermal activity helps life survive glacial cycles" in the journal Proceedings of the National Academy of Sciences, chose Antarctica to understand how terrestrial species survived the ice ages that began over 2 billion years ago.
The researchers noted that Antarctica provides "a unique setting" for this study because "the continent has experienced repeated glaciations that most models indicate blanketed the continent in ice, yet many Antarctic species appear to have evolved in almost total isolation for millions of years, and hence must have persisted in situ throughout. How could terrestrial species have survived extreme glaciation events on the continent?"
Moreover, Antarctica has at least 16 volcanoes that have been active since the last ice age came to an end some 20,000 years ago.
“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,” Crid Fraser from the Australian National University and an author on the paper said in a press release. “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.”
After examining thousands of records of Antarctic species, collected by previous researchers, Dr. Fraser and his team noted that there were more species close to volcanoes. The number of species decline as one moves farther away from them.
“This pattern supports our hypothesis that species have been expanding their ranges and gradually moving out from volcanic areas since the last ice age,” said Aleks Terauds from the Australian Antarctic Division, also an author on the paper.
The team looked at various mosses, lichens, and bugs found in Antarctica today. About 60 per cent of Antarctic's invertebrate species are found nowhere else in the world. In fact, “they have clearly not arrived on the continent recently, but must have been there for millions of years. How they survived past ice ages – the most recent of which ended less than 20,000 years ago – has long puzzled scientists,” said Peter Convey from the British Antarctic Survey and an author on the paper.
During the ice age, a lot of species fled the region in search of warmer areas, and "the only species that were left in Antarctica were those that couldn't get off," Fraser told Becky Oskin of LiveScience.
Researchers say that the study based in Antarctica can be applied to other icy regions of the planet. In addition to this, “Knowing where the ‘hotspots’ of diversity are will help us to protect them as human-induced environmental changes continue to affect Antarctica,” said Steven Chown from Monash University and an author of the paper.
