‘Gypsum,’ Oppenheimer gasped, recognizing the immaculate nature of what was otherwise a nondescript mineral.
But here it possessed a purity the likes of which he’d never seen. He began easing his way into the cave, staring in awe at the crystals and the flickering water. The strange scent he’d detected earlier tainted the air around him, and he recognized it as ammonia. A flickering motion on the cavernous ceiling caught his eye, and he looked up to see bats roosting in their thousands above him, their wings fluttering as they clung to their rocky domain. As they did so, he saw an occasional droplet of fluid fall from the heights, dropping into the water with a tiny splash and ripple, the cause of the endless shimmering of the surface.
Slowly, placing his feet near the edge of the pool, Oppenheimer peered over the edge. There, deep below the surface, he watched the tiny droplets fall through the beautifully clear water to join a bizarrely colored deposit deep beneath the surface, a kaleidoscopic multitude of fungi and mosses. Oppenheimer guessed that the droppings in the water must clear overnight when the bats were out hunting, settling on the bottom of the pool. In the reflection from the surface of the water that illuminated his wrinkled face, Oppenheimer saw his own smile beaming back at him like a shimmering ghost as a disembodied voice echoed through the cave around him.
‘It’s guano.’
He whirled to see Lillian Cruz watching him from the entrance to the chamber. Oppenheimer regarded her for a moment and then decided that she was no threat to him as he turned back to the water.
‘The guano has ammonia in it,’ he said, almost to himself.
Lillian stepped into the chamber, gesturing to the water. ‘It also has high levels of phosphorus and nitrogen,’ she said. ‘Along with ammonia it contains uric, oxalic, phosphoric and carbonic acids, various earth salts and nitrates.’
Jeb Oppenheimer’s mind was working overtime as he nodded to himself, gesturing to the giant gypsum crystals soaring above the chamber.
‘The gypsum and sulfur crystals mean speleogenesis: cave forming by sulfuric acid dissolution,’ Oppenheimer said. ‘The limestone cavern would have formed from the bottom up, in contrast to the normal top-down carbonic acid dissolution mechanism of cave formation. Sulfuric acid, derived from hydrogen sulfide, would have migrated from nearby oil deposits.’
‘The cave then floods over time with water draining through fissures from the ground above, creating these pools,’ Lillian added.
Oppenheimer nodded eagerly, gesturing up at the crystals with his cane. ‘The water falls,’ he said, ‘hitting the crystals and sometimes taking with it bacteria that were encased within the crystals when they formed millions of years ago, bacteria like Bacillus permians.’
Lillian nodded.
‘The bacteria fall into the water and mix with the guano at the bottom. Phosphorus in guano is an essential plant macronutrient,’ she said, ‘that’s why it’s used so heavily in fertilizers. The guano, laden with the bacteria, are kept in solution by the water in the pool. The bacteria, provided with a nutrient source by the guano, are reanimated and come into contact with all manner of mosses, fungi and bottom-feeding invertebrates.’
Oppenheimer’s laugh rattled out in the chamber, echoing back and forth around them as he spoke.
‘Some insect and invertebrate species are semi-aquatic, and others live on the surface. They consume the bacteria-laden guano, and are likewise consumed by the bats that hunt them!’ Slowly he turned to face Lillian, his wrinkled features alive now as finally, after so many years, he realized that he had found something that had existed in folklore for millennia. ‘The bats carry the bacteria, giving them their unusually long lifespans. They also process the bacteria through their gut and excrete many of them back into the water, or spill blood through injury into the pool.’
Lillian nodded, and despite the fact that he knew she hated him, she smiled.
‘Which over time ladens the water with the very fluids the bats have ingested, alive with a form of Bacillus permians that has evolved within these caves to live symbiotically within mammals.’
‘But what was the fuel?’ Oppenheimer struggled to understand. ‘What metabolism was required to sustain them for such long periods inside human beings?’
Lillian no longer held the truth back from Oppenheimer. In fact, she appeared to enjoy revealing to him what she had learned. ‘Iron, from the hemoglobin in blood,’ she replied. ‘Anyone who carries the infection will suffer from anemia if iron supplements are not provided in their diet.’
Oppenheimer looked at her pleadingly, like a child who has misbehaved yet yearns desperately for one last chance.
‘But how could it have made the transition to humans through a single encounter?’
Lillian regarded the old man for a long moment before replying.
‘Cross-species communication is possible in bacteria through something known as quorom sensing. The bacteria use it to coordinate gene expression via the density of their population. If there’s enough of them present in a biological species, the genes are activated and any infection shows symptoms.’
‘My God,’ Oppenheimer exclaimed. ‘Like the bioluminescent luciferase in fish that glow underwater, produced by Virbio fischeri. The gene cannot be expressed by a single cell, only when the population is large enough does the production of luciferase begin.’
‘The bacteria’s ability to express the gene is only activated when enough are consumed by the host species,’ Lillian confirmed.
Oppenheimer gasped, touching his head with one hand.
‘The only people who have ever been down here long enough to consume enough of the bacteria to activate them were those Civil War soldiers. Which means that they must have got their infection from…’
Oppenheimer stared at the beautiful waters at his feet as Lillian took a few paces forward to join him. Her voice, soft as it was, carried throughout the cavern and into Oppenheimer’s ears with the words he had once believed he would never hear.
‘This is the water,’ she said quietly. ‘This is the elixir, the real fountain of youth. Ellison Thorne and his men drank the water here while they waited for the Confederate army to pass them by in 1862. They did not age from that day onward.’
Oppenheimer, his eyes alight with joy, let his cane fall onto the rocks beside him as he got down on his knees, tears dripping from his face to ripple into the water.
‘And this is our ticket out of here,’ he whispered to his own reflection. ‘They dare not shoot us, if we’re uninjured and already carrying the infection.’
Slowly, he lowered his lips and they finally touched the surface. It was icy cold, clear, finer than the most expensive wine he had ever tasted. It surged through him as though he were forcing ice cubes down his throat, filled him with a tingling sensation as though his very nerve endings were sparking electricity onto the charged air in the chamber.
Finally, Oppenheimer stopped drinking and turned as he knelt beside the water, looking up at Lillian Cruz. He smiled broadly, just in time to see Lillian’s features melt into an expression of pure hatred as she lunged down and grabbed the back of his head and plunged it beneath the surface. As the freezing water swallowed his head, Oppenheimer heard Lillian’s voice shouting at him above the bubbles and splashes as he fought for his life.
‘You wanted to be here so much? Now you can damned well stay here!’
Oppenheimer’s ruined lungs ached, his aged heart thumped in his emaciated chest and his eyes bulged as he fought the urge to breathe. The clear view of the bottom of the pool swirled and starred as his vision faded. He was losing consciousness when he saw Lillian’s hand plunge into the water beside his head, holding a small plastic container that held what looked like a ball of iron surrounded by flesh. Water from the pool filled the container, and then it vanished again as a black cloud descended over his vision. He heard a faint voice from somewhere on the periphery of his consciousness.