"Many of the species we sequenced are what we would expect to find in a lake," Rogers said. "Most of the organisms appear to be aquatic (freshwater), and many are species that usually live in ocean or lake sediments."
For Shtarkman, who came to BGSU from St. Petersburg, Russia, the project has proven so engrossing that he foresees a possible lifetime of study around it. "It's a very challenging project and the more you study, the more you want to know," he said. "Every day you are discovering something new and that leads to more questions to be answered. In studying the environmental DNA and RNA, we ask how similar are these sequences to those of sequences from organisms already identified in national databases. We are tracing the evolution and the ecology of the lake itself.
Before 35 million years ago, Antarctica had a temperate climate and was inhabited by a diverse assemblage of plants and animals. About 34 million years ago, Rogers said, a "huge drop in temperature occurred" and ice covered the lake, when it was probably still connected to the Southern Ocean. This lowered sea level by about 300 feet, which could have cut off Lake Vostok from the ocean. The ice cover was intermittent until a second big plunge in temperature took place 14 million years ago, and sea level dropped even farther.
As the ice crept across the lake, it plunged the lake into total darkness and isolated it from the atmosphere, and led to increasing pressure in the lake from the weight of the glacier. While many species probably disappeared from the lake, many seem to have survived, as indicated by Rogers' results.
Rogers's group had worked for several years on identifying and studying organisms in the Vostok accretion ice using a procedure involvi
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Bowling Green State University