Studinger, a geophysicist at the Earth Institute at Columbia's Lamont-Doherty Earth Observatory, and colleagues studied Lake Vostok and its surroundings, and discovered that the earth's crust changes dramatically from one side of the lake to the other, as shown by data on gravity, magnetism and topography. The research, funded by the National Science Foundation's Office of Polar Programs, suggests that Vostok lies along a faultline, in a cavity formed when two areas of crust crumpled together.
An earthquake and aftershock captured by the team's instruments also supported the conclusion that the subglacial lake's thermal energy comes from tectonic processes. This was the first earthquake ever detected in East Antarctica, a region not previously thought to be seismically active.
Lake Vostok and the mountains around it are completely invisible from the surface of the Antarctic continent. Says Studinger, "It's fascinating to stand on a flat, glaring white expanse of ice, and know that deep below you, 4 km below, is a fragile world of strange beauty."
The lake is kept liquid because of the enormous pressure of its ice cover. About 80 other subglacial lakes have been discovered, but Vostok is by far the largest.
The "boundary conditions" of Vostok--including its ice and rock structure and the mountains and valleys that influence the flow of ice and water--have worked together to support the development of a unique ecosystem that "may contain microorganisms with distinct adaptations to such an extreme environment," the authors write. These microbes are supported by nutrients and small amounts of thermal energy introduced through faultlines, while other nutrients come into the lake in sediment that is scraped from the surrounding rock by rivers of flowing ice (the lake's ice flow was documented in an earlier paper in Nature).
Data collection was an exercise in extreme conditions as well. The team spent three weeks living in tents in temperatures that never rose above –28 degrees Celsius (-22 degrees Farenheit). At 11,440 feet above sea level, Vostok's air is thin and leaves researchers short of breath as they carry out their tasks. Studinger, who stayed on in unheated tents with only four colleagues for an additional week of data collection, describes long days spent engaged in unglamorous activities such as lugging car batteries by snowmobile to instrument stations. "You have to like the cold," he says.
The current paper provides the first comprehensive maps of Lake Vostok's ice thickness, geological framework, and the terrain under and around the lake as well as an understanding of how these factors influence water flow and other pieces of the Vostok ecosystem. In the future, the Columbia team hopes to design an observatory that can be inserted into the lake so that Vostok can be studied without introducing any microorganisms from the outside world.
The Earth Institute at Columbia University mobilizes the sciences and public policy in pursuit of a sustainable future. Directed by international economist Jeffrey D. Sachs, the Earth Institute's more than 800 scientists are engaged in teaching, research and outreach in dozens of countries, working across disciplines to reduce poverty, hunger, disease and environmental degradation. The Lamont-Doherty Earth Observatory is the only research center in the world examining the planet from its core to its outermost atmosphere, across every continent and every ocean. From global climate change to earthquakes, volcanoes, shrinking resources, environmental hazards, and beyond, LDEO scientists continue to provide the basic knowledge of earth systems that must inform the difficult choices necessary for wise stewardship of our planet. For more information, visit www.earth.columbia.edu.
Journal
Earth and Planetary Science Letters