When I first ventured into the Gulf of Mexico in the 1950s, the sea appeared to be a blue infinity too large, too wild to be harmed by anything that people could do.

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.

We have to look in the mirror first. What are we doing? How can we make a change? It always starts with looking in the mirror. Every individual can. Every individual can make a difference either by proactively doing something positive or by doing nothing. That's a decision, too.

It's mainly the high-end luxury market now that drives much of the fishing in the sea. It's not feeding the starving millions. It's feeding a luxury market.

Any astronaut can tell you you've got to do everything you can to learn about your life support system and then do everything you can to take care of it.

Ocean acidification - the excess carbon dioxide in the atmosphere that is turning the oceans increasingly acid - is a slow but accelerating impact with consequences that will greatly overshadow all the oil spills put together. The warming trend that is CO2-related will overshadow all the oil spills that have ever occurred put together.

Ironically the very energy, the very basis of how we know what we know, has been reliant on having an energy source [necessary] to build rockets to go to the moon and Mars, to support airplanes that fly, and satellites to give us our communication.