Perhaps the internationally recognized symbol of science fiction fandom is the rocket ship, and I have no reservations with that choice. Having read a fair cross-section of Golden Age material over the years, I’d be willing to make a small wager that implied or actual travel beyond the troposphere occurs in upwards of ninety percent of it.

But I didn’t grow up in the Golden Age of the ’30s and ’40s. When I was a child, as suffused as popular cultural depictions of SF still were (and continue to be) with spacefaring imagery, other themes, speculations, and what-ifs had begun crowding in at the edges. In fact, as a voracious and omnivorous upper-elementary reader, I read an enormous amount of juvenile science fiction without ever taking my adventures off-planet.

Instead there were contemporary riffs on Jules Verne’s Journey to the Center of the Earth, Sir Arthur Conan Doyle’s Lost World, and many, many deep sea adventures. I found myself particularly drawn to this secret watery world, returning to it again and again in novels and non-fiction.

I didn’t pay any attention to author names back then and I wasn’t reading the masters in any case. Nameless, work-a-day juvenile fiction writers were the ones to fire my imagination, and they did a darn good job at it, too. I was quick to check out Journey Under the Sea and Return to Atlantis, entries #2 and #18 in the popular Choose Your Own Adventure book series. I have vivid memories in my mind’s eye of deep-sea subs and underwater bubble-dome cities, an amalgamation of imagery from many more “proper” novels, though the details of their individual plots have long since washed away.

Heck, even if I weren’t a reader, underwater cities as either our past or future were a perennial of ’80s and ’90s cartoons. A quick Googling of a few of my favourites brings up several examples: episode 151 of the Teenage Mutant Ninja Turtles, “The Lost Queen of Atlantis”; season one, episode 12 of Captain Planet, “A World Below Us”; Mighty Max’s tenth episode, “Less Than 20, 000 Squid Heads Under the Sea.” All of which is to say, the twelve-year-old me was as well versed in fictional underwater cities as my grandfather might have been in imaginary alien planets at the same age.

There are good reasons for this. The tantalizingly unknowable nature of the deepest parts of the ocean resonates with the same brain parts as alien planets and distant galaxies. The scant science that we’ve attained so far can be as absorbing as the fiction it inspires.

I pretty much memorized a book from my elementary school library about creatures of the deep, checking it out more times than I can guess. It included thumbnail sketches of vaguely plausible marine myths like the Loch Ness monster and the Kraken (nothing so blatantly supernatural as the Flying Dutchman, of course), vital stats on actual known beasts like the giant squid (first known only from the vicious sucker wounds it left on sperm whales), and only halfway ridiculous speculations about giant eel (based on huge, dead “juveniles” found decaying on sandy shores).

Intermixed with the science and history lessons were fiction excerpts. A short story of a man wrestling against rubbery tentacles in the shallow water of a cave. The opening chapter of Jaws.

You’d think all these maybes and what-ifs would be out of date by now. But decades later, the mysteries remain. In common with space exploration, we have expanded the marine frontier only a little since we first dipped our toes into it. This is why both non-terrestrial settings remain such, if you’ll excuse the term, fertile ground.

And the connection between the two mysterious settings is an old one. H.P. Lovecraft’s enduring mythos explicitly tied together the inky blacknesses of outer space and ocean deep. The weird fiction author envisioned an uncaring universe where humanity’s place might be likened to the film of mold in a neglected bathroom tub. The great spacefaring races of the past could now be found — where else? — down below. In a sunken city, “[i]n his house at R’lyeh, dead Cthulhu waits dreaming”. (Lovecraft’s At the Mountains of Madness also brought in another classic SF frontier setting, the frozen wastelands of the poles.)

Thematically, it makes sense. Both the sea and the stars seem deceptively close, until we try to make the journey and find our earth-dwelling bodies profoundly unfit for the environment. Within the confines of our planet, the little we’ve seen of the deep sea is more alien than anything else we’ve ever encountered, and the deeper we go, the weirder it gets. And both locales inspire an overwhelming sense of our own smallness.

Even the question of alien intelligence might be answered by marine biologists rather than SETI. Unlike dolphins or chimps, cephalopods like octopuses and squid split off from us long before our common ancestor had anything resembling a brain. They developed their mental abilities completely independently from ours, and the more we study them, the smarter they seem. What remains to be seen is whether they’re a fundamentally different kind of smart.

Of course it’s one thing to see the deep ocean featuring in television fluff and books for pre-teens. What about modern SF for adults? Flooded, post–climate change worlds are featured in Steven Gould’s Blind Waves and Stephen Baxter’s Flood, but the action remains mostly at or near the surface and isn’t really to do with ocean exploration.

There’s Michael Crichton’s Sphere, also a movie, and there’s James Cameron’s The Abyss, also a book (novelized by Orson Scott Card, weirdly enough). Of an older vintage, I’ve only recently discovered that John Wyndham once got his feet wet with the sea monster tale, Out of the Deeps. I haven’t read it, yet, but it’s John Wyndham, so I daresay I’ll pick it up.

But recently, what I’ve been most enjoying is Peter Watts’s excellent Rifters series. Reading through the prologue of Starfish was like coming home. The opening narrative mentions all the old myths, centuries-old “weird news” of strange, rotting discoveries washed up on shore, speculations of both an academic and Ripley’s Believe It or Not! nature.

The novel proper is dark, gritty, and about as hard as hard science fiction gets. A marine biologist himself, Watts could likely provide a peer-reviewed citation for every science fictional conceit he introduces in his books. And this is no optimistic, gee-whiz-it’s-the-future Atlantis 2.0. Irresistable, paranoiac pressure over top of claustrophobic tin cans is what we get here. Just as space opera has moved on from Edgar Rice Burroughs’s planetary romances, so have the ocean trenches moved on from Verne’s 20,000 Leagues, and this is the proof of it.

Frankly, my feelings about the deep ocean are about the same as my feelings about other planets. I wish we could get on with it already, build our underwater city and our moon base both before another century is finished. But saving that, I’ll rely on any good book I can find to transport me to my beloved bubble dome under the sea. I might not even rule out choosing my own adventure.

J.J.S. Boyce is a writer, educator, and semi-pro omelette chef. He can frequently be found writing at the Green Man Review, Library Journal, and Care2. He also maintains a meta-narrative at his blog, The Back of the Envelope.