“But how do they stand the pressure down there?” Ra-Havreii asked.

It was practically the first thing he’d said to her since the shuttle. Fortunately, Melora didn’t have to respond directly to him. She called up a cross-section graphic, pointing to an array of small, glassy spindle shapes within them, and addressed the group. “They have an internal skeleton of silicate spicules. Up top, the spicules are loosely distributed, giving them some additional structural strength but leaving them fairly flexible. As they descend, they’re compressed further and further, the spicules coming together into a tight, geometric array that braces them against the pressure. As with the pure barophiles, the silicate framework contains and directs their molecular machinery the way cell walls do in our kind of life.”

“That’s fascinating, Commander,” Vale said, “but how does it connect the barophiles to the surface life?”

“Sorry,” Melora said. It was easy to get caught up in the wonder of this. “The critical thing is what the bathyplankton do once they’re down there. They feed on the metals and heavy elements that are part of the saline layer’s biosphere, the residue given off by the barophiles.”

“Which they in turn consumed from the clathrates in the mantle,” Onnta said.

“Exactly. And once they’ve stockpiled on metals, they swim upward until they reach the interface with the normal ocean. Then they spread fins that let them catch convection currents that carry them back up to the surface. The barophile life functions fall dormant, they drift upward, and finally their normal life functions engage again.”

Vale’s eyes widened. “And once they’re up there, being plankton, most of them end up getting eaten by bigger critters.”

Melora nodded. “Except enough of them survive to reproduce and start the cycle over again.”

“But they’re how the metals get back up from the mantle to the upper ocean. They’re what makes it possible for life to exist on the surface.”

The Elaysian couldn’t help grinning, despite the gravity of the situation. “An entire biosphere, a whole sentient civilization—it wouldn’t exist without these tiny, invisible creatures. Chamish suspects the barophile biosphere evolved first, driven by the energy of the magnetic dynamo, and that these bathyplankton somehow developed the ability to spread up to the ocean surface and take advantage of a new energy source, sunlight. Maybe they initially relied on some kind of organic molecules that could function well at intermediate pressures and marginally at surface pressures, and eventually replaced them with molecules better suited to surface life. Finally some of them evolved into forms that lived permanently on the surface and lost their extraneous barophile compounds, and the rest of the surface biosphere evolved from those.”

“But what matters,” Vale said, “is that the surface life depends on the barophile life for its survival.”

“Yes, ma’am.”

“And the barophile life is dying.”

“Yes, ma’am.”

“Because we thought shooting an asteroid would be a helpful thing to do.”

“Well…we did mean well.”

Vale sighed. “What exactly will happen if we don’t fix this?”

“Gradually, more and more of the barophiles will die. They’ll sink to the mantle, and there won’t be enough surviving barophiles to bring up enough clathrates. That’ll lead to a crash in the bathyplankton population, and that’ll leave the surface life with progressively worsening metal deficiencies. Meanwhile, with the magnetic field patterns permanently disrupted, the surface life will continue to behave erratically or have difficulty performing necessary tasks. Remember how on Earth, many cetaceans would beach themselves and die because the noise from human ocean vessels confused and blinded their echolocation sense?” Vale nodded, looking embarrassed. “It’s a similar principle. There’s no telling how much the Dropletians’ navigation, mating cycles, and so on could be thrown off by this. It could endanger whole species even without the excess violence this is producing among the sea life.

“In time, the contamination will dissipate; the dust will either use up its exotic charges in the dynamo layer or will sink to the mantle, get locked in clathrates, and dissipate its charge into the ice. The surviving barophile life will recover, and there will probably be enough dormant bathyplankton left to resume the nutrient exchange with the surface. But not before there’s major loss of life on the surface, possibly even a mass extinction.”

Vale shook her head. “So with a few phaser shots and two torpedoes, we kill a whole biosphere. That’s efficient.”

“Don’t forget the antimatter canisters,” Melora replied, earning a glare.

“What about the squales?” Xin asked. “Could their biotechnology protect them?”

“If anything, I’d say it makes them more vulnerable,” she shot back. “They’re dependent on so many other species that I doubt they could weather an extinction event. Not without enormous loss of life, at any rate.”

There was a pause before Vale spoke. “Just for the sake of argument…if Riker and Lavena are still alive down there, somehow, what are their chances?”

Melora shook her head. “They’d succumb to metal deficiencies before this became an issue. If they managed to escape the crazed predators.”

Vale glared at her. “Somehow, that’s not very comforting.”

LUMBU

The landing was fairly rough, since Krotine brought the Armstrongin on antigravs for the last few hundred meters. They made a water landing in one of the city’s wide canals and secured the shuttle under a bridge; luckily, travel through this portion of the canal was blocked by two large ferries at either end, both unable to move with their electrical systems and lights burned out from the pulse. In all likelihood, the shuttle would remain undiscovered for a few hours, at least.

It took the team half an hour to reach the hospital on foot, using tricorders on proximity scan to avoid encountering any Lumbuan citizens. Fortunately, Ree’s jamming field did not prevent tricorder operation, enabling the team to scan the hospital’s structure and determine an optimal stealth entry route. It was difficult for a Vulcan, a Boslic, a Caitian, and an Orion, all giants by Lumbuan standards, to make their way through the police perimeter undetected; but Tuvok had decades of experience at stealth and his teammates were well-trained. Hriss in particular was able to move with the soundlessness of a felinoid predator, but the lithe Krotine was nearly as light on her feet. Dennisar had a harder time of it, particularly since it was difficult for him to squeeze his bulk through Lumbuan doorways. Had Tuvok known that this world would be Ree’s destination, he would not have picked Dennisar for the team. But it could not be helped now. As Dennisar attempted to squeeze through a narrow maintenance passage into the hospital, he inadvertently produced a noise that drew the attention of a police officer guarding the perimeter. But Tuvok was able to waylay her with a nerve pinch before she could catch a clear sight of them or raise the alarm.