By Ann M. Simmons for The Los Angeles Times

They are the lifeblood of our planet, responsible for more than half of the oxygen we breathe. They regulate the climate, provide a major source of protein for 3 billion people, and millions of livelihoods — including 1 of every 6 jobs in the United States — are connected to the marine environment.

But the world’s oceans are under extreme duress, and humans are primarily to blame.

“I think we sometimes take it for granted, especially if you are located someplace where you don’t see the ocean every day,” Catherine A. Novelli, U.S. undersecretary for economic growth, energy and the environment, said during a recent interview with The Times.