The famous environmentalist known for her work on marine conservation is Sylvia Earle. She is a prominent marine biologist, explorers, and author, with a passion for oceanic health and preservation. As a former chief scientist for the National Oceanic and Atmospheric Administration (NOAA), Earle has been an advocate for protecting marine ecosystems for decades. Through her initiatives, such as Mission Blue, she strives to establish marine protected areas and raise awareness about the dangers of overfishing and pollution. Her contributions have inspired numerous individuals and communities to become active in marine conservation efforts worldwide.