Modern oceanography divides the deep sea into three zones: the bathyal, the abyssal and the hadal. What a cadence those terms form—each more profound than the last. The farther down we go, the less we know: the floor of the Marianas Trench has been less studied than the surface of Mars. “What passes in those remote depths…we can scarcely conjecture,” wrote Jules Verne with relish in 1870—conscious that where science had been unable to reach, fantasy could prosper.
I went, as a boy, through a sea-monster phase. Maybe we all do. It took me to H.P. Lovecraft’s octopoid god of evil, the Dread Cthulhu. It took me to the tentacled Kraken of Tennyson’s poem, that sleeps “far beneath in the abysmal sea”, among “enormous polypi” and “huge sponges of millennial growth”, waiting for the time when he will rise “roaring” to the surface.
And of course it took me down 20,000 leagues with Captain Nemo and his crew of black-clad outcasts aboard the submarine Nautilus, to see narwals, orcas and the mega-squid, “poulps”. Rereading Verne’s book, I’m reminded of how drastically it fails as a novel (scant plot, absurd ending), and how magnificently it succeeds as a magic-carpet ride. “You are going to visit the land of marvels,” Nemo promises our narrator, Pierre Aronnax—and he does.
But the true wonders of “Twenty Thousand Leagues Under the Sea” are natural. There are scenes that have stayed with me: the Nautilus reaching the South Pole, where it is caught and nearly crushed in a white tomb of ice; Nemo and Aronnax making their night ascent of an Atlantic volcano, passing through seaweed jungles from which shine the eyes of “giant lobsters” and “titanic crabs”, until they reach the crater as it plumes bright lava into the black water. Most amazing—and least plausible—is when the Nautilus noses its way through the tunnel that Verne imagines joining the Red Sea and Mediterranean, miles below the shimmering Sinai.
Each chapter also contains Aronnax’s loving lists of the organisms he sees through the glass viewing-windows of the Nautilus: the “pearl-oysters” and the “wolfthorn-tails”, the “medusae” and the slow-growing “blood coral”. He is a classic 19th-century naturalist: spellbound by the beauty of species, but unbothered by the slaughter of single creatures. He and Nemo are quite happy to tuck into dinners from a conservationist’s nightmare: “turtle soup made of the most delicate hawksbills”, “fillets of the emperor-holocanthus”. They hunt sea-otters, and shoot dead low-flying albatrosses from beneath the waves. Ned, the Canadian harpoonist, yearns to impale every cetacean he sees.
Two visions of the oceans compete in Verne’s novel. On the one hand, they are so vast as to be invulnerable—what Nemo calls “The Living Infinite”. On the other, Verne senses their future fragility—and that a time may come when their “creative power” might be less than “man’s instinct for destruction”. Nemo refuses to kill except to meet needs; Aronnax prophesies that the “barbarous and inconsiderate greed” of humans will “one day cause the disappearance of the last whale in the ocean”.
A century and a half later, and Verne’s fears have been proved broadly right. As water warms, coral reefs bleach, over-fishing rises and marine biodiversity declines, the upper realms of the sea no longer seem secure. Way down in the hadal zone, though, the ocean still goes about its chilly business—and the Kraken waits.