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.

The value of sharks' lives is now widely understood to be more important than their value as products. And when you have sharks in an area, it's a sign of good health. They're top predators, which means they feed on old, sick, and slower fish, keeping an entire population healthy.

Since I began exploring the ocean in the 1950s, 90 percent of the big fish have been stripped away. Tuna, sharks, swordfish, cod, halibut, you name it, the numbers have just collapsed. Also, about half of the coral reefs are gone, globally, from where they were just a few decades ago.

Forty percent of the United States drains into the Mississippi. It's agriculture. It's golf courses. It's domestic runoff from our lawns and roads. Ultimately, where does it go? Downstream into the gulf.

I hope for your help to explore and protect the wild ocean in ways that will restore the health and, in so doing, secure hope for humankind. Health to the ocean means health for us.

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.

Meat reared on land matures relatively quickly, and it takes only a few pounds of plants to produce a pound of meat.