Research just published by the British Antarctic Survey has shown that volcanoess may have preserved some Antarctic life during past ice ages. Is findings were published in the March 10 edition of Proceedings of the National Academy of Scientists.
From time to time in earth’s history cooling periods allowed ice to spread out from the poles, locking the world in ice ages. Some scientists think that the entire planet was covered by an ice sheet for a time about 650 million years ago. This is the snowball earth hypothesis.
t entirely accurate, at least for Antarctica. There, volcanoes helped keep plants and animals alive as temperatures dropped.
The team reached that conclusion after a survey of over 39,000 Antarctic organisms, including mosses, lichens, and worms. The most populous areas of the continent were found to be around 16 volcanoes that are active now, or have been active at some time since the last ice age 20,000 years ago.
According to Professor Peter Convey of the British Antarctic Survey, nearly 60% of the continent’s invertebrate species are found nowhere else. Those creatures are not recent arrivals on the continent. How those creatures survived the last ice age has been a scientific mystery.
Scientists had wondered how plants and animals adapted to climate change in the past. The possibility that volcanoes or geothermal vents may have played a role, the “geothermal glacial refugia” hypothesis, may have preserved life during ice ages, had not been tested before the British Antarctica Survey project. If that hypothesis is correct, then volcanoes helped species survive many ice ages.
Ceridwen Fraser of Australia National University and Aleks Teruad of the Australian Antarctica Division examined previously collected data on Antarctica’s plants, mostly mosses and lichens, and primitive animals like worms.
The survey of Antarctic organisms combined with spatial modeling of the populations showed they were concentrated around areas of geothermal activity. Ice- free land and ice caves preserved by the relative warmth allowed the organisms to survive. Ice caves created by geothermal vents could be dozens of degrees warmer than the outside air for example. When the ice receded the organisms could spread out from those warm spots.
Fraser’s team studied the distribution of species around areas of geothermal activity. The concentration of species was found to decline with distance from the hot spots. This was especially true for plants such as mosses. The results tend to support the claim that plants and animals rode out the ice age near areas of substantial geothermal activity and spread out from there.
According to the team’s paper, the results reveal some unexpected insights into how various species have coped with past climate change. Results also point to the important of geothermal activity in preserving and promoting biodiversity.” The paper also notes that survey results indicate where to look for other biodiversity “hot spots” in Antarctica. Locating these hotspots will aid in future Antarctica conservation efforts.
Fraser said the geothermal glacial refugia hypothesis, the formal name for this concept, could be extended to other parts of the world and to other glacial periods. Research could show whether the same geothermal hot spots had played a role in animal and plant survival outside Antarctica.
Geothermal activity associated with volcanoes may well have preserved life on earth during past ice ages, and not just in Antarctica.
By Chester Davis