dr. ruth gates is director of the hawaii institute of marine biology. she spends most of her time here in these waters - studying what's happening under the surface. >> ok ruth where are we headed today? >> today what i'm going to show you is corals that are different in color; white brown or dead. >> different levels of health then? >> exactly. >> it's a small crew. dr. gates and myself... team members jen davidson and beth lenz, and the boat's captain. john 'lj' benson. this won't be leisurely... we're racing the elements. in the mountains overlooking the bay, a storm is threatening. it's an ominous day to go scuba diving, but science doesn't wait for perfect weather. near our dive site, beth and jen jump in with snorkel gear to help us zero in on the reef below. the event that brought us here is called bleaching. higher than normal water temperatures cause corals to expel the symbiotic plant cells which provide them food. without the algae the corals begin to starve...turning healthy brown coral, ghostly white. this year's bleaching has been so perva