Getting Into Deep

"Scuba diving is like driving a four-by-four through the woods, without your widows up, air conditioning on, music blasting . . . You're not only removed from the environment, you're disrupting it. Animals are scared of you. You're a menace."

When writer James Nestor heard this from a freediving researcher, he didn't disagree. After all, he writes, "The constant gurgle from my scuba regulator scares everything around me; it's like I've gone bird watching with a leaf blower strapped to my back. And the wetsuit, tank and knot of tubes around my body prevent me from even feeling the seawater." With that in mind, Nestor overcame his fear of freediving, learned to go long and deep, and produced a fine new book, Deep; Freediving, Renegade Science, and What the Oceans Tells Us about Ourselves, that any active or armchair scuba diver will surely relish.

To tackle his own fear of freediving, Nestor studies under Hanli Prinsloo, the South African national record holder. Freediving, she says, is more than just holding your breath, it's a perception shift -- don't kick down the doorway to the deep, slide into it. By following her techniques, he begins his first day by holding his breath for under a minute and, by the end of the day, for more than three minutes. We follow him to freediving competitions, where, at 40 feet, the ocean begins pulling you downward, at 150 feet you enter a dream state, at 250 feet "the pressure is so extreme your lungs shrink to the size of fists, and your heart beats at less than half its normal rate," and at 436 feet, a diver's chest compresses from 50 inches to 20 inches.

We meet competitive freedivers who disappear during dives, panic and surface unconscious. In addition, we learn firsthand about the Master Switch of Life, "the physiological reflexes in the brain, lung and heart, among other organs, that are triggered the second we put our faces in the water. The deeper we dive, the more pronounced the reflexes become, eventually spurring a physical transformation that protects our organs from imploding under the immense underwater pressure and turns us into efficient deep-sea-diving animals. Freedivers can anticipate these switches and exploit them to dive deeper and longer." It's even triggered when we splash cold water on our faces in the morning.

While the extremes of freediving drive Nestor's book, I was especially taken by his study of deep-diving cetaceans, their behaviors and what seems almost like extraterrestrial talents. Nestor hooks up with a cadre of interesting characters, including Fred Bayle, a photographer and shark conservationist who has dived as deep as 200 feet off Malpelo Island, Colombia, to tag upwards of 150 hammerheads. We learn that smooth dogfish sharks have such acute electrical sensors, they can detect electrical fields five million times weaker than any human can detect. Many scientists believe that the species, which can sense electrical fields in their prey, navigate by sensing the earth's magnetic field. Some scientific experiments have shown that humans also subconsciously navigate by the earth's magnetic field.

Nestor organizes his book by depth, taking us down with dolphins to 1,000 feet, down with sperm whales to 10,000 feet, and eventually down 28,000 feet to the hadalpelagic region, where unique sea life never leaves. To get himself 2,500 feet deep, Nestor visits the west end of Roatan and joins up with Karl Stanley, who operates the Idabel, a three-person submarine he designed. He runs the Roatan Institute of Deepsea and, for $800 a person, takes scientists and tourists to explore the Cayman Trench. Crunched into the observation space with another passenger, Nestor is amazed at the underwater meteor showers, specks of detritus trickling to the sea floor. At 2,550 feet, an enormous comb jellyfish blinks blue, the red, then purple, then yellow, and then all colors flash at once. "Bioluminescent animals use light to startle, distract, lure and communicate," he writes, and describes how squid, anglerfish and other deep-sea critters that never see sunlight use their eyes to pick up the faintest illumination. Giant squid use bioluminescence to communicate with other squid, perhaps using something similar to Morse code. While the Idabel creaks and groans, it's a thrilling and sensational trip.

Sperm whales dive to 10,000 feet, and Fabrice Schnöller, an engineer by profession, has spent years freediving and recording their clicks, credas and codas. Nestor joins him on dives and on one of them, a 35-foot bull sperm charges him head on, then turns away with a "rapid burst of coda clicks so powerful that I could feel them in my chest and skull." Schnöller told him, "That's not coda . . . and he's not talking to you . . . he was looking at you to see if he could eat you."

Schnöller believes a whale's echolocation is so refined that when they echolocate our bodies, "they perceive that we have hair, big lungs, a large brain . . . perhaps they recognize that we're fellow mammals, that we have the potential for intelligence." (That's the rogue science referred to in the subtitle, perhaps more fantasy than science.) However, they can detect a 10-inch squid at more than 1,000 feet, with the most precise and powerful echolocation of any animal; their clicks can be heard several hundred miles away, with a maximum of 236 decibels; and they would blow out eardrums from hundreds of feet away and, scientists speculate, "vibrate a human body to death." Schnöller says he once touched the nose of a sperm whale calf and "felt a sudden shock of heat rush up his arm . . . The energy from the clicks coming out of the calf's nose was enough to paralyze Schnöller's hand for the next few hours." Schnöller theorizes that sperm whale clicks are "more like fax machine transmissions, which work by sending out microsecond-length tones across phone lines to a receiving machine, which processes those tones into words and pictures . . . human language is analog, sperm whale language may be digital."

Nestor's journey also takes him to the Florida Keys to visit scientists stationed in the Aquarius, the world's only underwater laboratory, and to Japan to dive with women in their 60s, 70s and even 80s, who still making a living freediving to net fish.

So, my fellow divers, I can't imagine that anyone who has had a chance to slip below the surface and marvel at the life there won't find this a fascinating read. Nestor, a fine journalist (he has written for Outside, Men's Journal and the New York Times) with a keen eye, has produced the best underwaterfocused book since Shadow Divers a decade ago. It's a fine adventure and a thrilling ride all the way from the surface down to 28,000 feet, and back.

Deep, 268 pages, is available in hardback or on Amazon Kindle. If you click on Deep's book cover on our "Editor's Book Picks" web page ( www.undercurrent.org/UCnow/bookpicks.shtml ) to order through Amazon, Undercurrent gets about five percent of the sale price, which we then contribute to a good cause: saving our oceans. In fact, if you buy anything from Amazon through Undercurrent -- from a vacuum cleaner to a bottle of vitamins -- we'll get a contribution.

-- Ben Davison