A windless day, sunlight filtered through high clouds. We are about 1,000 feet over south San Francisco in Eureka, the first zeppelin to fly over American soil since the Hindenburg explosion. In the gondola, ateam of scientists from NASA's Ames Research Laboratory in nearby Mountain View observes the hundreds of acres of coastal ponds below, a patchwork of vivid green, orange, and red. Each pond has been isolated by levees from the action of tides; as the water in the ponds evaporates, a residue of salt is left behind. For a hundred years, the salt has been harvested by the Cargill Company. Now, a 15,000-acre parcel of this land has been returned to the state of California, to be restored to wetlands.
展开▼
