Census of Marine Life

Great white whales. Schools of fish so thick they slowed boats. Sea monsters that could swallow a sailor whole. The last one may still be the stuff of lore, but scientists are using a curious series of census tools to gather evidence of an ocean that, as recently as decades ago, fairly teemed with marine life, far bigger and more plentiful that what's found in today's oceans.

Scientists surveying the submerged Macquarie Ridge, which stretches from New Zealand almost to the Antarctic Circle, have discovered a water world teeming with life. Tens of millions of starfish-like creatures live on an underwater mountain dubbed "Brittlestar City," whose unique shape and location make it possible for these animals to survive in such crowded conditions.