Into the Drowning Deep

by Mira Grant

  Gregory didn’t answer. They stood under a sky filled with a million stars, and the night had never seemed so vast, or so cold. Neither of them went near the rail. They were both sensible enough to be afraid of what they might see if they looked down at the unforgiving sea, which roiled and rolled and did not care that they were alive, or that they were small and far from home. The sea would continue as it always had, indifferent to the concerns of humanity.

  Had they looked, they might not have seen anything. Daryl was inexperienced compared to Gregory, and more, he was letting his nerves get the better of him; he was seeing danger in every corner, and allowing it to blind him to the danger that was actually lurking. He would have seen the smooth sweep of the hull, the fruit of human labor and innovation, intended to protect them from the dangerous waters. He would have seen how high up he was, and how far the mermaids would need to climb, and felt this rendered him safe, somehow. Protected, sheltered, like a small fish choosing to believe the coral reef can offer genuine protection from the jaws of the eel, the arms of the octopus.

  Gregory, who had sailed on vessels like this one in the past, might have fared a little better. He might have seen the scrapes along the bottom fifteen feet of the hull, the ones that hadn’t been made by normal wear and tear. They didn’t match anything he’d ever seen before. It was difficult for the modern mind to jump to “monsters” as the answer to what could have made those scratches on the side of the ship, those little nicks and rips in the metal. Monsters didn’t make any sense.

  But they had sailed off the edge of the map, into the waters the cartographers had marked with “Here be monsters” and a picture of something terrible and toothy—a warning to unwary sailors that this was, perhaps, not the best route to carry them home.

  Daryl and Gregory remained on their high deck, in their seemingly safe place, and didn’t notice the claw marks trailing from the waterline up the side of the ship. They didn’t see the places where the rails dripped with sticky mucus, secreted from specialized glands, greasing the path of creatures that had evolved as far away as possible from the treetops and open plains of the cradle of humanity. They didn’t understand.

  Following the marks would have taken them to the water, and below; the nicks and scratches didn’t stop where the sea began, but proliferated, becoming deeper, more common, more pronounced. There was no hesitation in the marks under the surface. There the creatures that had made them had not needed to contend with gravity, to fight for their grips against the constant motion of the sea. They could simply cling, claws hooking onto metal, and plan their next moves.

  Below that, where the bulk of the Melusine created a patch of artificially calm water, was the photic zone—a seemingly false name now, with the sun down and the waters as dark as they had ever been. But light could pierce these depths when someone turned on one of the Melusine’s running lights, or when the scientists activated another of their clever little toys. Drones and autonomously propelled cameras moved through the dark beneath the ship, turning the water into a teeming web of motion.

  The deepest any of them dove was fifteen feet below the hull. They were small machines; they needed tethers to keep them from being swept away by the current, and their operators needed a clear signal to continue issuing commands. Diving any deeper would have resulted in losing the connection, and possibly consigning expensive research equipment to the abyss.

  So none of the cameras saw the forms lurking another fifteen feet down, hovering suspended, staying stable with sweeps of their webbed hands. The glitter of their hair would show up on the recordings, but it was faint, low, in an area known for the bioluminescence of its night things. There might be a few operators who would put together what that distant sparkling meant, who might realize they were being watched … but then again, there might not. It was so faint, after all. It was so delicate. And even with the evidence of their eyes and Heather’s and Ray’s deaths speaking to the truth of the matter, even with the captain putting the ship on alert, there were still people on the Melusine who didn’t believe in mermaids. They were chasing myths, not monsters. The evidence of their eyes would be, not ignored, but certainly discounted, given less weight than the things they knew.

  The things they knew were the things that were likely to get them killed.

  In the dark below the hull, the front line of mermaids lingered. There were nineteen of them, eyes turned toward the outline of the boat, hair drifting in tangled, light-spangled clouds. The light it put off wasn’t enough for human eyes to pick out fine details, but for the mermaids, whose pupils had expanded to their widest, hungriest state, it was more than sufficient. Their hands moved in constant conversation, all speaking and answering at the same time, never pausing, clawing their way toward consensus one signed disagreement at a time.

  Half the mermaids advocated for immediate assault. They remembered other ships that had sailed through these waters, with their steep sides and their soft centers. They remembered the taste of man-flesh, even if they hadn’t shared in the bounty already taken from the Melusine. It was sweeter than dolphin, more filling than squid; if this ship was half as full as others had been, it could feed the entire colony for as much as a month—even the eldest—and allow them to lay in stores against the next change in the waters.

  The other half called for caution, for patience, for moving slowly in the pursuit of a cleaner kill. They, too, remembered the taste of man-flesh, but unlike their more eager cousins, they remembered harpoons, bullets, the reality of death at the hands of these strange air-breathing creatures. There were few things in these waters that could kill an adult mermaid. They were too fast, too deadly, and too clever. The two-legged things in their artificial floating reefs were born killers, and they would do what they were made for if they were given half a chance.

  The argument raged, tucked safely away beneath the waves. When it was done, things would continue. When it was done, things would change.

  “Scalpel.”

  Tory dropped the tool into Dr. Toth’s palm, unable to tear her eyes from the mermaid’s chest cavity. The bullets had ripped through several internal organs (including a lung; Tory thought Dr. Toth might never stop glaring at the Abneys for that), but the beauty of the body was in its symmetry: for everything that had been destroyed, there was usually a parallel organ still intact, waiting to be taken out and studied.

  “Thank you.” Dr. Toth leaned forward, positioning herself within the butterfly span of the mermaid’s ribcage, which had been snipped open and spread using a tool intended for spreading the ribs of dolphins. It was a bit too aggressive for the task: several of the thin, delicate ribs had been snapped in the process, breaking like kindling. Only the fact that the specimen was already damaged had made it possible to continue with the tools and facilities provided. Data loss on this scale was no longer a concern.

  Pressing her scalpel against the membrane surrounding one of the upper organs in the mermaid’s chest, Dr. Toth said conversationally, “The structure appears to mimic the pericardium, leading me to believe that fluid retention is an essential part of the creature’s biology. Based on location in the body, I believe I am about to reveal the heart.”

  She had been narrating her every move for the cameras. Tory admired how smooth her voice was, and how careful she was to say “I think” and “I believe,” rather than making definitive statements. She didn’t know she was about to reveal the heart. She might be slicing into a ball of fat, or a nesting site for some symbiotic parasite. Everything about this creature was a mystery, and by never claiming anything for certain, Dr. Toth made sure she would never be caught in a lie.

  The scalpel bit into the membrane, which opened to reveal the knotted muscle of the creature’s heart. Dr. Toth continued, “The heart appears to have multiple chambers. Further study will need to wait until I have finished my initial assessment.” She cut the heart free with quick strokes of her scalpel, lifting it out of the chest cavity and placing it in one of the waiting pa
ns.

  Blood gushed from the heart as it was set down. The fluid was thin and viscous, as much yellow as red. It was not mammalian blood. Nothing mammalian could have survived with that fluid running through its veins.

  “The left side of the chest was severely damaged when the creature was killed; the tissues will be analyzed, but as there’s no way to guarantee a lack of cross contamination, they won’t be used in the formal results.” Dr. Toth reached into the right side of the chest. “All the organs in the upper body are separated by what look to be unusually large, spacious membranes similar to the one around the heart. Hypothesis: the gas or fluid contained in these sacs allows the creature to balance its water retention, and hence weight, depending on where it hangs in the water. There may be an element of conscious control to the retention and release of water.”

  “That would also change the effects of pressure on the body,” said Dr. Lennox, not quite interrupting, but sliding into the space between her words. Dr. Toth shot him a hard look. He didn’t seem to notice. “These creatures are moving between incredibly different environments just by going from the Challenger Deep to the surface. Coming into the open air is almost a step too far. They should explode, unless they have a way to compensate for pressure changes.”

  “Why, because they have lungs?” Dr. Toth got her hands under the offending structure, lifting it out of the mermaid’s chest cavity. “Please note that the lung in question is two-thirds the size I’d expect in a mammal of this size, and does not show the same complexity of form. Victoria?”

  “Here,” said Tory, sliding a tray under the mermaid’s lung. Dr. Toth put it gently down.

  “Take this to the secondary dissection table; we’re going to get into it in a moment,” said Dr. Toth.

  “Yes, Doctor,” said Tory, and retreated with the lung, watching the light strike rainbows off its smooth, grayish surface. It was a color like but unlike the connective tissue hidden beneath a salmon’s scales. It smelled oily, astringent; if she’d been asked to identify the species on smell alone, she couldn’t have done it. She supposed that was exactly right. Something this new shouldn’t be too similar to something old.

  Dr. Toth continued to work. “I have a secondary lung here,” she said, a note of excitement in her voice. “The previous lung was more like our classic understanding of the organ. This is more like an air bladder. It’s the sort of structure I’d expect to find in a snakehead or other fish capable of surviving out of the water.” She eased the secondary lung free, holding it up.

  It was small, dense, and almost pitch black. No blood dripped from the severed tubing that had connected it to the rest of the organs. Instead a brackish liquid trickled out, intensifying when she turned the organ in her hand. The liquid was accompanied by a strong fishy smell, like something decaying on the beach. Dr. Toth’s smile grew.

  “I understand now,” she said beatifically, and set the secondary lung in one of the waiting trays before turning to Mr. Blackwell. “I know how they’re doing it.”

  Theo raised an eyebrow. “How?” he asked.

  “They don’t just have a dual breathing system. We expected that. It made sense. Gills for underwater, lungs for above. Sure, that would make them evolutionarily unique and more than a little redundant, and it wouldn’t explain the pressure problem, but it would enable them to exist.”

  “The pressure problem?” asked Olivia. She managed to make the question sound intelligent, despite the fact that it was what Bill Nye the Science Guy would have called a straight line: it was there purely to get the people who knew more than she did to perform for the cameras.

  Dr. Toth turned to her, looking baffled. Like everyone else, except perhaps Tory, she’d forgotten about Olivia as soon as the woman had gone to have her makeup fixed. Olivia hadn’t made any effort to reinsert herself into the conversation. People who knew what they were doing were working: she was just here to record it all for posterity and, when necessary, to make sure they verbalized their work.

  “Oh,” said Dr. Toth. “Yes. The pressure problem. Water has weight. So does air, but the weight of air is negligible compared to the weight of water. Because water is an immersive medium, most creatures that live in it don’t notice it’s there—they’ve adapted to the pressure. They can handle it. They can’t all handle sudden changes, which is why deepwater fish have been known to explode when pulled to the surface by a fishing net. We know these mermaids live deep but surface to hunt. Not unknown—many species of squid do that, as do some types of shark—but rare enough to be worth remarking upon. I’d been wondering how they were able to accomplish the transition. It’s harder on air breathers like us, you see. Our lungs are filled with gas. Gas doesn’t do well with pressure changes. Whales and dolphins have incredibly powerful lungs. They can hold their breath for hours. That lets them dive at a measured pace, and come back up the same way. There’s a reason young whales tend to stay closer to the surface.”

  “We know the mermaids don’t behave like that,” said Dr. Lennox. Dr. Toth shot him an irritated look, but didn’t say anything. He was young, handsome, photogenic; he would play well on the camera, and she wanted this to come out. She wanted people to watch and understand.

  They were going to die. She’d been sure of that since the moment she spread the mermaid’s ribs and saw the puzzle-piece organs nestled inside, waiting to share their mysteries. Some of those mysteries had been self-solving, so obvious that every incision and examination just confirmed what she already knew. The secondary lung, for example. The conclusions were clear. There had never been any other way for this to end.

  “The mermaids can’t raise their young at the surface; unless they undergo a metamorphosis so profound that juveniles are literally unrecognizable, which is unlikely—it’s metabolically inefficient—there’s no way they could be nurturing their infants above the bathypelagic level without being seen. Further, we know they’re true water breathers. They’re not amphibians, or if they are—”

  “And they are,” said Dr. Toth calmly.

  Dr. Lennox shot her a sidelong look and continued, “—if they are, they’ve somehow pulled off a redundant system that nothing else on Earth has achieved. They’re air breathers and water breathers.”

  “Dr. Toth,” said Olivia. “As the supervisory biologist on this necropsy, do you have a comment?”

  “First, you are correct that I am a biologist: I have a degree from the University of Hawaii, and another from Columbia.” Dr. Toth shot Dr. Lennox a look of barely veiled contempt. “Despite my focus on supposedly nonexistent creatures—one of which, I will note, is on my dissection table—I am fully competent, and can analyze my findings without the need for a dissenting voice.”

  “Are you saying you have a contradictory suggestion?” asked Dr. Lennox.

  “The axolotl,” said Dr. Toth. “They’re amphibians. Native to Mexico—or they were, before they became extinct in the wild. Still popular in the pet trade, and since they’re all captive bred at this point, I suppose that’s for the best. At least it means there are still axolotls in the world. They were viewed as primitive for a long time, because even the adults retained their external gills. Frogs can’t breathe underwater, you see. Tadpoles can, but once they transition into their adult forms, that capability is lost. They become air breathers, like mammals. Like all other adult amphibians. Except for the axolotl, which likes the water a lot, and doesn’t care much for the land. The axolotl never becomes an air breather.”

  “It’s an adult with attributes of its own juvenile form,” said Dr. Lennox, smoothly retaking the reins of the conversation. “Scientists believe the axolotl was a more standard salamander once, before going back to the water.”

  “Wouldn’t it have been easier for the axolotl to never leave the water in the first place?” Olivia somehow managed to make the question sound perky and even smart. Tory’s heart ached for her. They were both back to work in the wake of Ray’s death, but while he’d been a shadow on the wall for Tory,
he’d been the world for Olivia.

  For the first time, she realized how much she genuinely cared about Olivia’s feelings. Maybe this wasn’t just a shipboard fling after all.

  Dr. Toth shook her head. “It would have been easier, yes, but evolution has never been about easy. Evolution takes risks. It puts things in new environments, and leaves most of them there to die when they don’t work out. But some, if they’re quick, or lucky, it allows to come back to where they started. We’ve always wondered why there weren’t more saltwater amphibians. They existed once, in huge numbers, before multiple extinction events cast the seas into the shape they have today. Being an amphibian in the middle of the ocean might not seem to make much sense, but neither does being a dolphin, an otter, or any one of a number of forms that would be more suited to life on or near land, and which nature has chosen to cast utterly adrift.” Dr. Toth’s hand found the table where the mermaid had been laid out. Gently she put the scalpel down. Still gentle, she turned and brushed the mermaid’s tangled hair back from the line of its scalp.

  The motion dislodged some of the water trapped there. A small eyeless shrimp scuttled into view for a heartbeat before scuttling away again, vanishing into the hair.

  “Air-breathing creatures have difficulty descending too deep because of the bends. Bubbles in the blood. Nitrogen poisoning. And the pressure, of course. You can never discount the pressure. Water-breathing creatures struggle making the transition between the abyssopelagic and photic zones. The absence of pressure is as fatal for them as the presence of pressure would be for us. It’s a way of isolating one ecosystem from another. Never the twain shall meet. But these beauties … Ah.”