Sylvia Earle dives with a group of jack fish during an expedition.[Photo/China Daily]

The US Library of Congress deems her a Living Legend. Over the past five decades, the mother of three has logged more than 7,000 hours undersea, discovering tens of thousands of species of aquatic life. Even at 80, she continues to spend three months a year on ocean expeditions. Her work has earned her the nicknames Joan of Arc of the Ocean, Hero for the Planet, and best of all, Her Deepness.

She is Sylvia Earle.

When not immersed in the ocean, she's advocating for it. During her eighth visit to China last week, the renowned US marine biologist and pioneering oceanographer promoted shark conservation by giving a lecture and launching the Chinese version of her 2014 book, Blue Hope: Exploring and Caring for Earth's Magnificent Ocean, in Beijing and Shanghai.

"China is a uniquely important country. The people of China will determine so much of the future of our planet in the coming decades," she said during her speech at Tsinghua University in Beijing. "That's why I am honored to be here and to have the opportunity to speak to you directly, about what I care about: the ocean, its iconic wildlife, and the species that depend on it: That's us."

According to the scientist, sharks are "some of the most magnificent fish in the sea". "Sharks have roamed the ocean for more than 400 million years ... Without sharks, the ocean will suffer," she told China Daily.