Use your power to do whatever it takes to secure for humankind an enduring place on this little blue speck in the universe - our only hope.

Never again will we have this good a chance as we now have to find an enduring place for ourselves within the natural systems that keep us alive. It's a sweet spot in history. That's why this is such a critical time.

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.

The sudden release of five million barrels of oil, enormous quantities of methane and two million gallons of toxic dispersants into an already greatly stressed Gulf of Mexico will permanently alter the nature of the area.

If Darwin could see what we now see, what we now know about the ocean, about the atmosphere, about the nature of life, as we now understand it, about the importance of microbes - I think he would just beam with joy that many of the thoughts and the glimpses of the majesty of life on Earth that he had during his life, now magnified many times over.

The burning of fossil fuels has altered the amount of carbon dioxide in the atmosphere so rapidly and so abundantly that now, we are driving not just the warming trend, not just the sea level rise that is a consequence of the warming trend that is melting polar ice and alpine ice, but also [ocean acidification].

My first breath was just...it just seemed impossible that you could actually breathe underwater. I knew in my mind it was possible, but actually experiencing it was such a gulp of joy and I feel it every time I go under the ocean. I love doing it, to be able to feel weightless, to spin on one finger, to do somersaults, to be like a graceful ballerina - even with a huge tank on your back you can do the most extraordinary things.