If Sylvia Earle's older brother had never borrowed their neighbor's copper diving helmet and taken his kid sister for a dip in the Weeki Wachee River not far from their childhood home, there's no telling where the Explorer-in-Residence at the National Geographic Society would have ended up. Below the surface, Earle found an abundance of sea creatures that, curiously enough, were just as interested in her as she was in them. "It was exhilarating," she says, in her Big Think interview, "I thought that what we were there to do was go look at the fish underwater and I was amazed because the fish started gathering around looking at us. For me, that was a big breakthrough, that fish were curious." 
Four decades later, the oceanographer and founder of Mission Blue--a TED initiative to inspire people of all stripes to put their respective skills toward ocean conservation--has logged over 6,000 hours underwater and completed more than 50 research expeditions worldwide. Along the way, Earle's had a few breathtaking encounters. Her one hour interview takes us from a brief run-in with a 40 foot long humpback whale to an uncanny encounter with a lobster in the Florida Keys. "I certainly have never eaten a lobster since then," Earle notes. Sharks are scary, she admits, but it would be scarier if there weren't any around for us to see. "You should be afraid if you go down and don’t see sharks. That means the ocean is in trouble, and if the ocean is in trouble we’re in trouble."

After spending most of her life satisfying a personal desire to explore the oceans, Earle feels obligated to call other people's attention to how desperately our oceans need to be protected. "I can’t indulge myself as much as I once did as a young explorer, as a younger scientist. I now am compelled to share the news."