Sharks are beautiful animals, and if you're lucky enough to see lots of them, that means that you're in a healthy ocean. You should be afraid if you are in the ocean and don't see sharks.

The living ocean drives planetary chemistry, governs climate and weather, and otherwise provides the cornerstone of the life-support system for all creatures on our planet, from deep-sea starfish to desert sagebrush. That's why the ocean matters. If the sea is sick, we'll feel it. If it dies, we die. Our future and the state of the oceans are one.

This is a living planet. Look around. Mars, Venus, Jupiter. Look beyond our solar system. Where else is there a place that works, that is just right for the likes of us? It has not happened just instantly. It is vulnerable to our actions. But it's the result of four and a half billion years of evolution, of change over time. And it changes every day, all the time. It would be in our interest to try to maintain a certain level of stability that has enabled us to prosper, to not wreck the very systems that give us life.

Success underwater depends mostly on how you conduct yourself. Diving can be the most relaxing experience in the world. Your weight seems to disappear. Space travel will be available only to a few individuals for some time, but the oceans are available to almost everyone - now.

We want to believe that we can continue doing what we've done for the past thousand years and not worry about the consequences coming back to us.

We are not only warming the ocean and the planet as a whole, but we are also acidifying the ocean and changing its chemistry.

When I write a scientific treatise, I might reach 100 people. When the 'National Geographic' covers a project, it communicates about plants and fish and underwater technology to more than 10 million people.