White on top, but what lies beneath? Antarctica鈥檚 blanket of snow and ice sits atop a vast and rich landscape of volcanoes, rivers and lakes. Results from the first expedition to sample the sediment beneath the ice are revealing how the remnants of ancient forests are fuelling the communities that live there today.
Lake Whillans sits beneath nearly 1聽kilometre of ice in West Antarctica. Despite its heavy frozen lid, it is full of liquid water.
In January 2013, a US team drilled through the ice and sampled the lake鈥檚 water and the sediment beneath.
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The sediment contained microfossils of marine organisms and fossilised pollen from beech trees and conifers of the University of California at Santa Cruz told a meeting on subglacial Antarctic lakes held at Chicheley Hall near London last week.
The pollen dates back to before 34聽million years ago, at a time when Antarctica was a collection of lush forested islands separated by salty fjords. Both are providing much-needed nutrients to a completely different community that now occupies the area; the water samples from the lake revealed a thriving microbial community that was living in the pitch dark and at huge pressures and low temperatures.
Fish in the dark
鈥淚 like to think that the long-dead life from a much happier time is now feeding the modern microbial ecosystem,鈥� says Tulaczyk.
The team have found bigger things too. In January they drilled down to a nearby subglacial beach and were stunned to find fish and crustaceans living in the dark.
Ross Powell of Northern Illinois University says they have evidence the fish are stressed and struggling to survive, probably because they are starved of nutrients. They may have fled from an even worse environment, or could be early pioneers of a new subglacial world.
Nor is everything beneath the cap ice-cold. Previous expeditions have revealed seething volcanoes, and ones that erupted in the last couple millennia, punching large holes in the ice cap. Tulaczyk dropped thermometers into the lake bed at Whillans, and measured the geothermal activity.
鈥淲e found a huge heat flux, typical of places like Yellowstone,鈥� he says, adding that the region could be sitting on top of a geothermal hotspot. 鈥淭hat raises the possibility that there may be hydrothermal vents down there.鈥�
