“If it’s some kind of free-floating toxin, are you sure that’ll be far enough away?”
Irritation jabbed at her, colored with embarrassment when Nils’s worry only made her glance again at the oxygen gauge near the edge of her mask. She cut off whatever sharp reply she’d meant to make when the oxygen level dropped from 18 to 11 percent in the moment that she watched.
An instant later, she’d rocketed five meters back to the top of the polyp bed.
“Well?”
She clapped hands to both sides of her mask and frantically sought out the oxygen gauge while her lungs begged her to take another breath. But not yet, not yet—not until she knew what they’d done to her. She wanted to die knowing what the bastards had done.
The O2 gauge glowed a helpful green, telling Rahel that levels were considered optimal even before she specifically identified the reading of 21 percent. Her breath gusted out of her as though she’d been punched.
“OK.” She was surprised at how thoughtful and calm her own voiced sounded in her ears. “No, Nils.” She glanced back down through the darkness, toward the drop-off and the carpet of dying cells. “I don’t think three meters will be far enough.”
“Oh?” The lawyer sounded disgustingly eager. “Did you find something?”
Rahel pushed herself to lie even with the ledge through sheer force of will, digging her fingers into the muddy floor as if that would somehow hold her from toppling over into oblivion. “I’ve at least found the hint of something. Sadena’s got a problem with his water.”
“His water?”
She pointed, then remembered that Nils couldn’t see her and pulled her arm back to her side. “Down where the die-off occurred, my gas exchange system registered a drop in available oxygen. I thought there was something the matter with my suit, but when I got back up here, my oxygen level was back to normal.”
“Meaning what?” Nils asked, his voice sounding almost annoyed with confusion. “That there isn’t oxygen for the suit to process in the water ten meters below you?” Something that his tone said he found distinctly unlikely.
“Very good, counselor.” She rolled onto her back and sat up. “Would you like to go for double or nothing?”
“But I don’t understand.” Nils was obviously too disconcerted for recreational betting. “I thought water was always one-third oxygen—H2O. How can you not have oxygen when you’re in the middle of an ocean full of water?”
Rahel sighed and looked up toward the surface, wondering how easy this would be to explain with forty meters of sea between them instead of a halffull bucket of water and two glass bell jars. “Because that’s not the type of oxygen I’m talking about. The oxygen in H2O is busy being water, and you can’t get it to stop being water without running an electric current through it.” She peeked at the O2 gauge in her mask to ward off a sudden shortness of breath. “What I’m talking about is dissolved oxygen—little bits of oxygen that aren’t hooked up to hydrogen being water. When there isn’t any of that in the water, the suit can’t extract it out. That’s why skinsuits don’t work for long in a closed system like an aquarium, or why they’re not useful in swamp studies…” Whatever point she’d meant to make evaporated from her brain, burned away by the sudden brightness of her understanding.
“That still doesn’t tell me why this water’s lacking oxygen.”
“Because of the swamp,” Rahel said excitedly. She pushed up to her knees so quickly that she nearly lifted herself into a tumble. “Uriel’s swamp water is anoxic—it doesn’t have enough dissolved oxygen in it. That’s why it’s stagnant, why not much lives in it, why it smells bad—Nils!” She clapped a hand to the top of her head. “That’s where the hydrogen sulfide came from! Paval’s suit extracted it out of the standing swamp water!”
God damn. The Greens had a slander case against her after all.
“Wait a minute.” Nils cut across her ranting impatiently. “Are you telling me you think swamp water is leaking into the Odarkan and killing the stellar jellyfish? How?”
Rahel shook her head and felt around the back of her belt for the reach-stick. “Dunno.” She looked around as though that might enlighten her while paying the stick out to its full three-meter length. “Maybe by flowing along a rift in the shelf platform. Or maybe Sadena’s pumping someplace and didn’t feel the need to tell us. However it’s getting here, though, it’s coming through in pretty large quantities.”
“And you’re sure the water’s coming from the margin sloughs?”
“Not 100 percent sure.” Rahel had to be honest about that or scientific methodology wasn’t worth a damn. She clipped a sample flask to the reach-stick, then tied a cable to the other end before lowering it over the edge into the anoxic darkness. “But there’s one real quick way to find out.”
The churlish, rotten stench of hydrogen sulfide belched up at Rahel when her reach-stick broke the surface of the margin slough’s morass. She turned her face away with a little cough, and signaled the stick to pop caps on all the specimen jars arrayed along its length. Even a cloth filter mask didn’t do much to keep out the smell, and nothing did much against the insects. Rahel spent half her time batting buzzers and noseeums away from her eyes, the other half trying to get the lids back on the sample jars so she could retreat inside the pachyderm. She’d never been more grateful for water-tight surgical gloves and hip-deep waders.
“Is nature always this smelly?”
She glanced back at Nils as she withdrew the reach-stick from the filthy water. With one hand braced against the pachyderm’s open hatchway and the other holding a filter mask against his mouth, he looked like an unwilling attendant at an autopsy. Rahel doubted she could have convinced him to step down into the swamp water even if she needed him to.
“This is about as bad as it gets,” she admitted, wading back to join him. “Methane from large ungulate farts is pretty nasty, too. But it explodes, so at least you can have fun with it.”
Nils stumbled aside to let her climb past him into the pachyderm, then keyed the door shut once she was inside. “You’ve got to be joking.”
Rahel didn’t see the point in enlightening him.
Jynn looked up from the pilot’s station when she entered, but didn’t stand or say anything, only offering a nervous wave in greeting. Rahel acknowledged him with a nod. He’d insisted on piloting the pachyderm from the Startide to the sloughs because neither Rahel nor Nils was cleared by Feles Sadena to fly within Uriel’s atmosphere. “Mr. Sadena wouldn’t want me to start ignoring his own rules now, ma’am.” The fact that Rahel’s mobile laboratory was even more rigorously non-impact than any of Sadena’s aircraft wasn’t part of the equation. “Either I’m responsible for what flies outta here and where, ma’am, or we go to Mr. Sadena and you explain to him what you want to do. It’s not my place to make the rules.”
In the end, Rahel was just as glad to have Jynn along. He proved remarkably adept at keeping the pachyderm no higher than the skin of the water—“You been down underwater, ma’am. We can’t take you no higher in the air than this.”—and having him to pilot let her pull her gear together before they arrived at the sloughs. Unlike Nils, Jynn also seemed to feel no need to understand every little step of what she did along the way.
“Computer.” Rahel stopped in front of the pachyderm’s testing station and started unclipping sample jars one at a time. The inside of the ship already stank from the wet of her footsteps, and she despaired for a moment of ever removing the smell again. “Get ready for another collection set. Log this one as Urieclass="underline" Southeast Margin Slough, Sample Series #1.” She telescoped the reach-stick, tossing it into a basin for later cleaning, then stripped off her gloves and dropped them carefully into the disposal. “I’ll want a full work-up on resident chemosynthetic bacteria using the same criteria you applied to Odarkan Sea Series #3. Run a split screen comparison of the two series, and alert me as soon as you’re done.”