Sylvia A. Earle

And some people say nature doesn't need us.

And there is some truth to that because when you think about the history of the planet, four and a half billion years, and we are newcomers.

Our history goes back decades.

Maybe 300,000 years.

When you go in the ocean, you're swimming in the history of life on Earth.

The creatures who were there in the earliest days, I mean, at least they're more or less unchanged.

I mean, some of them, microbes, they continue to shape the world.

And we're just beginning to discover how important they are.

When you think about just one, we didn't know Prochlorococcus existed until 1986.

And now we know it generates about 20% of the oxygen that we breathe, as well as supplying oxygen to life in the sea.

Well, not too many people get to go up as astronauts either.

But what astronauts report back to us is life-changing.

And the images that they have brought back

This is Earth.

It's this little blue miracle in the universe that's also miraculous, but it's not very friendly to the likes of us.

This is it.

This is our home.

But astronauts can only see the surface.

And there are ways with satellites to kind of glimpse what's down a little bit below.

But you have to actually get into the ocean.