I've spent thousands of hours under water. And even in the deepest dive I have ever made, 2.5 miles (about 4 kilometers) down, I saw trash and other tangible evidence of our presence.

The Earth is a tiny blue speck in a universe of unfriendly options.

We still have the illusion that the ocean will recover. That even if we do have to lose sharks, people don't understand why this matters. The evidence is in front of us, and we fail to take it in and say, "Now I get it. Now I understand."

Like a shipwreck or a jetty, almost anything that forms a structure in the ocean, whether it is natural or artificial over time, collects life.

All through college, I had frequently been the only girl in a science class - which wasn't such a bad deal.

Nothing has prepared sharks, squid, krill and other sea creatures for industrial-scale extraction that destroys entire ecosystems while targeting a few species.

Ten percent of the big fish still remain. There are still some blue whales. There are still some krill in Antarctica. There are a few oysters in Chesapeake Bay. Half the coral reefs are still in pretty good shape, a jeweled belt around the middle of the planet. There's still time, but not a lot, to turn things around.