American oceanographer Sylvia Earle dedicates her life to preserving the oceans. In 1970, she led the first female team of aquanauts, a group of women living 15 meters deep for two weeks. She then discovers the effects of pollution on coral reefs and will spend her life alerting to its dangers. It will publish more than 200 scientific publications on this subject. In 1998, Time magazine named her Hero for the planet. Photo credit: Kip Evans