Deep, Dark Secrets Indeed

Though the first deep-sea expedition took place in 1931, humans still know little about what goes on miles below sea level. What we do know is startlingly strange, Tim Flannery writes in a look at two new volumes in the New York Review of Books—and a rising tide of sewage is contaminating Earth's final "final frontier" faster than it can be studied.

"Denizens of the deep" contend with harsh conditions—no sunlight, limited food, intense pressure, radioactive waste—but are canny adapters: Creatures that produce their own light abound, as do translucent shape-shifters and super-slow metabolisms. And their well-being is yoked to our own: Many of the fish we eat feed on these distant neighbors, who live in our toxic dumping grounds. (More ocean stories.)