The next time you're out in nature, stop, close your eyes, and listen.

That’s what Bernie Krause would like us all to do, before it’s too late to hear the full symphony of the natural world. Founder of the scientific field called "soundscape ecology," Krause has been recording the noises of our wild places, whether it's on land or at sea, since 1968.

He's created an international archive of over 5,000 hours of habitat recordings, featuring at least 15,000 identified organisms. Some regard his library as a national treasure.

Sadly, increasing human interference is muffling nature’s voices—from bird songs to wolf howls to insect footsteps. And many of an ecosystem's sounds, which he calls biophonies, have ceased playing forever.

“The orchestra is