By Stephanie Pappas
21 hours ago
A view of Lake Fryxell in the McMurdo Dry Valleys of Antarctica, where the surface ice never melts. New research finds that oxygen-generating bacteria live in the depths of these lakes, where the waters are mostly oxygen-free.A little oxygenated slice of paradise survives deep in an icy Antarctic lake, providing a window into what life on Earth may have been like before oxygen permeated the atmosphere.
Earth's atmosphere was relatively oxygen-free until about 2.4 billion years ago, when photosynthetic bacteria started pumping out oxygen as a waste product in the process of transforming sunlight into energy. This "Great Oxidation Event" reflects the point at which oxygen became widespread, but researchers now think photosynthetic bacteria evolved at least half a billion years earlier. However, the details of the transition from a low- to high-oxygen environment remain mysterious.
One possibility is that oxygen was locally prominent in some spots by 2.8 billion years ago — millions of years before it went global. If so, these oxygen pockets probably looked like the newly discovered oxygen hotspot in Antarctica.
"The thought is that the lakes and rivers were anoxic [oxygen-free], but there was light available, and little bits of oxygen could accumulate," study researcher Dawn Sumner, an earth scientist at the University of California, Davis, said in a statement.
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Topic: Oxygen Oasis Discovered in Antarctic Lake (Read 560 times)