南极沃斯托克冰下湖中存在生命体

Lake Vostok, buried under a glacier in Antarctica, is so dark, deep and cold that scientists had considered it a possible model for other planets, a place where nothing could live. However, work by Dr. Scott Rogers, a Bowling Green State University professor of biological sciences, and his colleagues has revealed a surprising variety of life forms living and reproducing in this most extreme of environments. A paper published June 26 in PLOS ONE (Public Library of Science) details the thousands of species they identified through DNA and RNA sequencing.

"The bounds on what is habitable and what is not are changing," Rogers said.

This is the fourth article the group has published about its Lake Vostok investigations. The team included Dr. Paul Morris, biology, who with Scott and doctoral student Yury Shtarkman conducted most of the genetic analyses; former doctoral students Zeynep Koçer, now with the Department of Infectious Diseases, Division of Virology, at St. Jude's Research Hospital in Memphis, performed most of the laboratory work; Ram Veerapaneni, now at BGSU Firelands, Tom D'Elia, now at Indian River State College in Florida, and undergraduate student Robyn Edgar, computer science.

Their work was supported by several grants, including two from the National Science Foundation, one from U.S. Department of Agriculture and one from the BGSU Faculty Research Committee. Together, the amount dedicated to the project was more than $250,000.

When thinking about Lake Vostok, you have to think big. The fourth-deepest lake on Earth, it is also the largest of the 400-some subglacial lakes known in Antarctica. The ice that has covered it for the past 15 million years is now more than two miles deep, creating tremendous pressure in the lake. Few nutrients are available. The lake lies far below sea level in a depression（洼地） that formed 60 million years ago when the continental plates shifted and cracked. The weather there is so harsh and unpredictable that scientists visiting must have special gear and take survival training.

Not only had most scientists believed Lake Vostok completely inhospitable to life, some thought it might even be sterile.

Far from it, Rogers found. Working with core sections removed from the deep layer of ice that accreted from lake water that froze onto the bottom of the glacier where it meets the lake, Rogers examined ice as clear as diamonds that formed in the great pressure and relatively warm temperatures found at that depth. The team sampled cores from two areas of the lake, the southern main basin and near an embayment on the southwestern end of the lake.

"We found much more complexity than anyone thought," Rogers said. "It really shows the tenacity（韧性，固执） of life, and how organisms can survive in places where a couple dozen years ago we thought nothing could survive."