Smack in the middle of the Pacific Ocean, 1,600 kilometers (1,000 miles) south of Hawaii, scientist Jeremy Jackson dives beneath the clear, blue water. Rainbow-colored corals--tiny sea animals--sway below. Jackson is exploring the coral reefs that make up the Palmyra Atoll, a group of reef islands that have grown along the donut-shaped rim of a submerged volcano. Jackson, an ecologist from Scripps Institution of Oceanography, is amazed at the vibrant reef around him. "Palmyra is one of the few remaining reefs in the world that is close to pristine," he says.
Hundreds of years ago, all of the world's coral reefs may have been as spectacular as Palmyra. But today, healthy ...