The air in the foam was under pressure, though: from the rock above, and—below sea level—from the surrounding water trying to force its way in. Air was constantly being lost to diffusion through the rock; the wind blasting out of this tunnel was the accumulated leakage from hundreds of square meters, but the same thing was happening, less dramatically, everywhere.
The lithophiles prevented Stateless from collapsing like a punctured lung, and sinking like a drowned sponge. Plenty of natural organisms were proficient at making gas, but they tended to excrete products you wouldn’t want wafting out of the ground in vast amounts, like methane or hydrogen sulphide. The lithophiles consumed water and carbon dioxide (mostly dissolved) to make carbohydrates and oxygen (mostly undissolved)—and because they manufactured “oxygen-deficient” carbohydrates (like deoxyribose), they released more oxygen than they took in carbon dioxide, adding to the net increase in pressure.
All of this required energy as well as raw materials; the lithophiles, living in darkness, needed to be fed. The nutrients they consumed and the products they excreted were part of a cycle which stretched out to the reefs and beyond; ultimately, sunlight on distant water powered everything they did.
Soon the surface was frothing and boiling, spraying calcareous droplets toward the camera like spittle. And it finally dawned on me that I’d been utterly mistaken: the dive had nothing to do with Edenite notions of “modern tribalism.” Whatever courage it required was incidental; that wasn’t being valued for its own sake. The point was to descend through the palpable exhalation of the rock, and to see with your own eyes what Stateless was: to understand the hidden machinery which kept the island afloat.
Rajendra’s hand appeared at the border of the image as he fitted the mouthpiece and switched on the air supply. Of course: all this seeping liquid would build up at the bottom of the tunnel. He glanced down once, at what looked like a dark, sulphurous pool, boiling with volcanic heat; in fact, it was probably chilly and almost odorless. Munroe had been right about one thing: you really had to be there. What’s more… the tunnel wind would be weaker at this depth than at the surface, because much of the leaking rock contributing to the total airflow was now overhead. Rajendra would have no trouble noticing the difference—but the view, alone, of gas escaping at ever greater pressure, suggested exactly the opposite.
As the camera plunged beneath the surface, the image flickered and then switched to lower resolution. Even through the turbulent, cloudy water, I could still catch occasional glimpses of the tunnel wall—or at least the wall of bubbles streaming out of the rock. It was a weird, disorienting sight—it almost looked as if the water was so acidic that it was dissolving the limestone right before my eyes… but once again, that impression would have been instantly untenable if I’d been down there in person, swimming in the stuff.
The resolution dropped again, and then the frame rate fell; the picture became a series of stills in rapid succession as the camera struggled to maintain contact. Sound came through clearly enough, though I probably wouldn’t have recognized distortion in the noise of bubbles breaking against a scuba mask. Rajendra glanced down; the view showed ten thousand pearls of oxygen streaming up through opalescent water— and nothing more distant than his knees. I thought I heard him inhaling sharply, tensing himself in preparation for touching the bottom—and then I almost sent the notepad tumbling down after him.
One still showed a startled, bright red fish staring straight into the camera. In the next image, it was gone.
I turned to the woman beside me. “Did you see—?” She had, but she didn’t seem at all surprised. The skin tingled all over my body. How thick was the rock we were standing on? How long was the cable?
When Rajendra emerged from the underside of the island, he made a noise which might have expressed anything from exuberance to terror; with a plastic tube in his mouth, and all the other acoustic complications, all I could discern was a muffled choking sound. As he descended through the subterranean ocean, the water around him gradually became clearer. I saw a whole school of tiny, pale fish cross the lantern beam in the distance, followed by a gray manta ray at least a meter wide, mouth stretched open in a permanent, plankton-straining grin. I glanced up from the screen, shaken. This couldn’t be happening beneath my feet.
The winch halted. Rajendra looked up, back toward Stateless, tilting the lantern on its pivot, swinging it back and forth.
Milky water roiled in a layer that clung to the underside. Fine particles of limestone? I was confused; why didn’t they simply fall? Even from strobed stills, I could see that this haze was in constant motion, surging rhythmically toward the hidden rock. I could also make out bubbles of gas, dragged down a few meters in some kind of undertow, before finally escaping back into the haze. Rajendra played the beam back and forth, improving his control; the lantern was obviously difficult to manipulate accurately, and I could sense his frustration—but after a few minutes his persistence paid off,
A stronger-than-average surge mixed an updraft of clear water into the milky layer above, parting the curtain for an instant. Beam and camera transfixed the event, exposing lumpy rock sparsely populated with barnacles and pale, frond-mouthed anemones. In the next frame, the image was blurred—not yet obscured by the haze of white particles, but crinkled, distorted by refraction. At first, we’d seen the rock through pure water; now we saw it through water and air.
There was a thin layer of air constantly trapped against the underside, maintained by the steady stream of oxygen escaping from the foamed rock.
This air gave the water a surface which could carry waves. Every wave which crashed on the distant reefs would send a twin diving beneath the island.
No wonder the water was cloudy. The underside of Stateless was being constantly scraped by a vast, wet, jagged file. Waves eroded the shoreline, but at least that stopped at the high-tide mark. This assault was going on beneath dry land, all the way to the rim of the guyot.
I turned again to the woman beside me, one of Rajendra’s friends. “The limestone detritus… tiny particles like that, must lose all their oxygen, all their buoyancy. Why don’t they just… fall?”
“They do. The white comes from engineered diatoms. They scavenge calcium from the water, mineralize it—then migrate up and paste themselves into the rock when the waves dash them against it. Coral polyps can’t grow in the darkness, so the diatoms are the only repair mechanism.” She smiled, hyperlucid; she’d been there to see for herself. “That’s what holds the island up: just a fine mist of calcium, fading away into the depths, and a few trillion microscopic creatures whose genes tell them what to do with it.”
The winch started rewinding. No one was near it; there must have been a control button for the diver, which I’d missed, or maybe it was preprogrammed, the whole dive calculated in advance to limit the risk of decompression sickness. Rajendra put his hand in front of his face and waved to us. People laughed and joked as he began his ascent; it was nothing like the mood when I’d arrived.
I asked the woman, “Do you have a notepad?”
“In the bus.”
“Do you want the communications software? You could keep the camera…”
She nodded enthusiastically. “Good idea. Thanks!” She went to fetch the notepad.
The camera had only cost me ten dollars, but the copy fee for the software turned out to be two hundred; I could hardly retract the offer, though. When she returned, I approved the transaction and the machines conversed in infrared. She’d have to pay for any more duplicates, but the program could be moved and erased for free, passed on to other groups of divers.