Science Now: Each spring in the Arctic, the freshet-flooding triggered by melting snow-washes vast amounts of carbon-rich soil from the land into the water-both fresh water and the ocean. That's of particular interest to scientists studying global warming, because in those waters much of the carbon that's being released from melting permafrost is oxidized by bacteria into carbon dioxide, says Rose Cory, an environmental scientist at the University of North Carolina, Chapel Hill. Carbon from surface waters amounts...