Columbia geophysicist Michael Studinger surveys Lake Vostok.
Since the 1996 discovery of a liquid lake, sealed for millions of years beneath two miles of solid ice, scientists have speculated about the novel life forms existing within. Located in the Antarctic, Lake Vostok is a pristine, ancient global environment that has sparked an international effort to develop exploratory methods without introducing modern contaminants.
The potential is monumental for gained knowledge on microbial evolution, the discovery of new organisms and enzymes with potential value to society, and the ability to correlate data with that of other planets under similar conditions. Robin E. Bell of Lamont-Doherty Earth Observatory and her colleagues have begun a three-year study of Lake Vostok with the goal of understanding the origin of the lake and the source of the lake water.
Their preliminary research results, published in the March 21 issue of the scientific journal Nature, reveal that although the lake is ancient, perhaps millions of years old, the waters of Lake Vostok are relatively young. Bell's paper demonstrates that over a period of 13,300 years, all of the water is removed by the overlying ice sheet and replaced from other sources. The lake water captured by the moving ice sheet is deposited as layers of ice along Lake Vostok's eastern shoreline. Exploring those ice layers is equivalent to exploring the lake itself.
Lake Vostok is one of the largest lakes in the world, 30 by 140 miles wide and 3,000 feet deep. Its waters have been hermetically sealed from air and light for perhaps as long as 35 millions of years under the tremendous pressure of a continental ice sheet. Until recently, scientists have been exploring the ice-core above the lake. Cored to within 328 feet of the lake's water surface, the ice layers reveal a 400,000-year environmental record with micro-organisms present throughout most of the core. Further coring was halted while scientists convened to develop systematic studies and methodology for further investigation without threat of contamination to the water.
"Our study is a critical step in the exploration of Lake Vostok," said Bell. "We are learning more about the interface between the water and the ice. Biology loves interfaces. The lake water captured by the ice sheet now can be traced to the east of the lake. These frozen lake water samples will record the passage of the ice sheet and the processes across the lake. The data show that the current research station on the lake may not be optimal for biological studies."
Through radar soundings over Lake Vostok, Bell and her team determined that the ice formation in the southern half of Lake Vostok, holds buckling patterns frozen into the ice sheet as it flows over the lake. Following the trends of the buckled ice patterns, scientists were able to construct movement trajectories across the lake.
They then calculated the time it took ice to move from the west side of the Lake to the east -- 20,000 years over a distance of about 35 miles. By examining the ice flux out of the lake, the team determined that every 13,300 years the ice sheet removes the equivalent of the entire volume of Lake Vostok.
As the ice sheet removes lake water like a continuous conveyor belt, lake waters must be replenished, either by melting of the ice sheet or by subglacial meltwater. The source of this water remains a mystery.
Bell said, "Lake Vostok is absolutely devoid of interference. The youngest water in it is 400,000 years old. It doesn't know anything of human beings, fossil fuels, or plastics. It is a window into life forms and climates of primordial eras."
This research is the first of a series of systematic studies on Lake Vostok. With an understanding of how the ice and lake interact and move, scientists can conduct informed research of this lake system.
The Lamont-Doherty Earth Observatory is one of the world's leading research centers examining the planet from its core to its atmosphere, across every continent and every ocean. From global climate change to earthquakes, volcanoes, environmental hazards and beyond, Observatory scientists continue to provide the basic knowledge of Earth systems that must inform the difficult decisions that will determine the future health and habitability of our planet. Click for more information.