A Door Into Ocean by Joan Slonczewski

barnacles raked his palm.
    â€œYou can’t swim,” Lystra noted as if to herself.
    â€œI can too!” he shouted. “I can swim all the way past Trollbone Point.”
    Lystra’s arm shot out and pulled him under, down toward the dim blueness. She’s drowning me, his mind screamed. He pried at the claw
that crushed his wrist and stretched his arm till it would snap. Nothing could slow this relentless plunge, deeper with every kick of Lystra’s powerful legs. A vise of water inexorably clamped Spinel’s chest; any moment now, his life would spill out in a stream of froth.
    Unaccountably, air burst around him. Spinel choked and splashed, and the sounds echoed hollowly. His arm struck something hard—the roof of a clear, glassy bell that enclosed enough space for himself and Lystra to tread water underneath.
    Lystra floated, her palms gliding in lazy circles. She waited for his breath to slow to normal. Then she turned to a rack of tools set in the bell. “Good,” she said, as she pulled a belt of tools around her waist. “Stay here till I’m done with the starworm.” She slipped out of the bell and spurted away, gliding in and out of the shadows cast by great branches above, until she reached …
    A green swath stretched beyond, perhaps as long as a market square. Tiny Sharers hovered at its mouth, which sprouted a radial pattern of stalks with bulbous ends. The body was bound to the branches above it by a spidery mooring, except for the tail, which swung ponderously and spewed a white jet in a long, waving curve. Spinel watched the beast, awestruck. Could this be a “seaswallower?”
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    The starworm was not a seaswallower, but a lesser cephaglobinid species. It fed on plankton and small fish filtered from the seawater pumping steadily through its gut. The stream from the gut of a score of starworms could propel a raft gradually, enough to keep the rafts together in a system of eight and to guide them into currents that did not veer too far poleward. To bind the starworms and steer their course, to clean their mouth filters and raise their hatchlings—these were jobs for Lystra and her sister wormrunners.
    As Lystra approached, two wormrunners already circled above the swaying stalks of the starworm’s mouth. Elonwy the Fearful was about Lystra’s age, but Yinevra the Unforgiving was the senior wormrunner responsible for all twenty starworms. Yinevra grimaced and lifted an accusing hand to demand, “Why late today, Lystra?” That left a bitter taste in Lystra’s mouth. The Valan creature had kept her back, for he could barely swim at all. Mercifully, Yinevra did not stop for a grilling. She was pale from need of oxygen, so she sped off to the airbell where Spinel had been left.
    What Lystra was late for was the time for “farsharing,” the sending
of news by way of the starworm’s song. The starworm produced its song in low-frequency sound waves from within its roiling gut. The form of the song could be directed to send news within hours all around the globe. Now, according to time-keeping clickflies, it was far-sharing hour for Raia-el.
    Already Elonwy had prepared a special bait, a good-sized red squid at the end of a grappling pole. Lystra kept herself prudently outside the reach of its arms. Elonwy held out to her another pole, Lystra grasped it, and together they maneuvered the squid into the treacherous vortex of the starworm’s maw. This sudden bulky mouthful slowed the pumping to a trickle, as the beast paused to ingest it.
    Now Lystra could swim safely to the lip, for a few minutes at least. As she neared it, she averted her eyes from the throbbing tunnel inside, almost furtively, almost the same way she avoided certain mental tunnels of her past and future … . She banished that thought and caught hold of one of the radial stalks of the “star” that rimmed the mouth. She sunk her feet into a valley