The wall of the tunnel grew visibly moist; Rajendra reached out and trailed his fingers through the chalky fluid. Water and nutrients penetrated every part of the island (even the center, although the dry, hard surface layer was thickest there). It didn’t matter that the rock here would never be mined – and the fact that the tunnel remained “unhealed” showed that this region had been explicitly programmed against regrowth. The lithophiles were still indispensable; the heartrock could never be allowed to die.

I began to make out tiny bubbles forming in the fluid clinging to the wall – and then, deeper still, visible effervescence. Beyond the edges of the guyot, Stateless was unsupported from below – and a solid limestone overhang forty kilometers long, strengthened by biopolymers or not, would have snapped in an instant. The guyot was a useful anchor, and it bore some of the load – but most of the island simply had to float . Stateless was three-quarters air; the heartrock was a fine, mineralized foam, lighter than water.

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.