Science: Putting On Ancient Airs

Dinosaurs, it seems, may have breathed easier than we do. Indeed, at a meeting of the Geological Society of America in Phoenix last week, two scientists stunned colleagues by reporting that 80 million years ago, the earth's atmosphere contained about 50% more oxygen than it does now. Geochemists Gary Landis of the U.S. Geological Survey and Robert Berner of Yale reached their startling conclusion after analyzing tiny air bubbles trapped in bits of amber, the aged and solidified resin of coniferous trees. They placed the amber inside a vacuum chamber, then cracked it to let the ancient air escape. They found that it was 32% oxygen, compared with 21% in the modern atmosphere.

If the findings are accurate, ideas about atmospheric evolution might have to be revised. The two admit the results "are still very preliminary," but they insist the method is sound.

Berner quickly dismisses speculation that a change in the oxygen supply had anything to do with the extinction of dinosaurs. "It was a very slow change, over millions of years," he observes. "And most organisms easily adapt." Next comes testing bubbles in 300 million-year-old amber.