On a routine expedition in 1987, oceanographers in the submersible Alvin were mapping the typically barren, nutrient-poor seafloor in the Santa Catalina Basin, off the shore of southern California. On the final dive of the trip, the scanning sonar detected a large object on the bottom. Piercing through the abyssal darkness down at 1,240 meters, Alvin's headlights revealed a 20-meter-long whale skeleton partly buried in sediment. On reviewing the dive videotapes, expedition leader Craig Smith and his team saw that the skeleton was probably either a blue or a fin whale. The creature appeared to have been dead for years, but the bones and their surroundings teemed with life—wriggling worms, centimeter-size clams, little snails and limpets, and patches of white microbial mats. The skeleton was a thriving oasis in a vast, desertlike expanse.