Richard A. Kerr
New Orleans--Things are looking rougher at the end of the Permian period, 250 million years ago. Just months ago, researchers determined that the largest known volcanic eruption on land took place in present-day Siberia at the same time as 90% of all genera in the oceans died out. Now they've stumbled on evidence of another assault--a sudden surge of carbon dioxide from the deep sea that allegedly poisoned marine life. A complex choreography of oceans and ice sheets could have sucked carbon dioxide into the deep sea, then disgorged it into shallow waters.